Lint Report

Overview

	Correctness
8	AppLinkUrlError: URI invalid
3	ForegroundServiceType: Missing `foregroundServiceType` attribute in manifest
1	UseSwitchCompatOrMaterialCode: Replace usage of `Switch` widget
	Security
1	UnsafeIntentLaunch: Launched Unsafe Intent
1	AcceptsUserCertificates: Allowing User Certificates
1	InsecureBaseConfiguration: Insecure Base Configuration
	Performance
25	NotifyDataSetChanged: Invalidating All RecyclerView Data
10	StaticFieldLeak: Static Field Leaks
2	NestedWeights: Nested layout weights
11	Overdraw: Overdraw: Painting regions more than once
1	UsableSpace: Using getUsableSpace()
	Accessibility
1	ClickableViewAccessibility: Accessibility in Custom Views
	Included Additional Checks (85)
	Disabled Checks (50)

URI invalid

../../src/main/AndroidManifest.xml:162: Android App Links' host attributes must be valid web domains

 159                 <category android:name="android.intent.category.BROWSABLE" />
 160 
 161                 <data android:scheme="http" />
 162                 <data android:host="*" />                                                           
 163                 <data android:pathPattern="/f/..*" />
 164             </intent-filter>
 165             <intent-filter android:autoVerify="true">

../../src/main/AndroidManifest.xml:172: Android App Links' host attributes must be valid web domains

 169                 <category android:name="android.intent.category.BROWSABLE" />
 170 
 171                 <data android:scheme="http" />
 172                 <data android:host="*" />                                                           
 173                 <data android:pathPattern="/..*/f/..*" />
 174             </intent-filter>
 175             <intent-filter android:autoVerify="true">

../../src/main/AndroidManifest.xml:182: Android App Links' host attributes must be valid web domains

 179                 <category android:name="android.intent.category.BROWSABLE" />
 180 
 181                 <data android:scheme="http" />
 182                 <data android:host="*" />                                                           
 183                 <data android:pathPattern="/..*/..*/f/..*" />
 184             </intent-filter>
 185             <intent-filter android:autoVerify="true">

../../src/main/AndroidManifest.xml:192: Android App Links' host attributes must be valid web domains

 189                 <category android:name="android.intent.category.BROWSABLE" />
 190 
 191                 <data android:scheme="http" />
 192                 <data android:host="*" />                                                           
 193                 <data android:pathPattern="/..*/..*/..*/f/..*" />
 194             </intent-filter>
 195             <intent-filter android:autoVerify="true">

../../src/main/AndroidManifest.xml:202: Android App Links' host attributes must be valid web domains

 199                 <category android:name="android.intent.category.BROWSABLE" />
 200 
 201                 <data android:scheme="https" />
 202                 <data android:host="*" />                                                           
 203                 <data android:pathPattern="/f/..*" />
 204             </intent-filter>
 205             <intent-filter android:autoVerify="true">

../../src/main/AndroidManifest.xml:212: Android App Links' host attributes must be valid web domains

 209                 <category android:name="android.intent.category.BROWSABLE" />
 210 
 211                 <data android:scheme="https" />
 212                 <data android:host="*" />                                                           
 213                 <data android:pathPattern="/..*/f/..*" />
 214             </intent-filter>
 215             <intent-filter android:autoVerify="true">

../../src/main/AndroidManifest.xml:222: Android App Links' host attributes must be valid web domains

 219                 <category android:name="android.intent.category.BROWSABLE" />
 220 
 221                 <data android:scheme="https" />
 222                 <data android:host="*" />                                                           
 223                 <data android:pathPattern="/..*/..*/f/..*" />
 224             </intent-filter>
 225             <intent-filter android:autoVerify="true">

../../src/main/AndroidManifest.xml:232: Android App Links' host attributes must be valid web domains

 229                 <category android:name="android.intent.category.BROWSABLE" />
 230 
 231                 <data android:scheme="https" />
 232                 <data android:host="*" />                                                           
 233                 <data android:pathPattern="/..*/..*/..*/f/..*" />
 234                 <!-- path pattern to handle deep link -->
 235                 <data android:pathPattern="/app/..*" />

AppLinkUrlError Correctness Error Priority 5/10

Missing foregroundServiceType attribute in manifest

../../src/main/java/com/nextcloud/utils/ForegroundServiceHelper.kt:31: To call Service.startForeground(), the <service> element of manifest file must have the foregroundServiceType attribute specified

 28     ) {
 29         if (isAboveOrEqualAndroid10) {
 30             try {
 31                 ServiceCompat.startForeground(                                                      
 32                     service,
 33                     id,
 34                     notification,

../../src/main/java/com/nextcloud/utils/ForegroundServiceHelper.kt:41: To call Service.startForeground(), the <service> element of manifest file must have the foregroundServiceType attribute specified

 38                 Log.d(TAG, "Exception caught at ForegroundServiceHelper.startService: $e")
 39             }
 40         } else {
 41             service.startForeground(id, notification)                                               
 42         }
 43     }

../../src/main/java/com/nextcloud/client/media/PlayerService.kt:68: To call Service.startForeground(), the <service> element of manifest file must have the foregroundServiceType attribute specified

  65                 putExtra(IS_MEDIA_CONTROL_LAYOUT_READY, false)
  66             }
  67             LocalBroadcastManager.getInstance(applicationContext).sendBroadcast(intent)
  68             startForeground(file)                                                                   
  69         }
  70 
  71         override fun onStart() {

For targetSdkVersion >= 34, to call Service.startForeground(), the <service> element in the manifest file must have the foregroundServiceType attribute specified.
To suppress this error, use the issue id "ForegroundServiceType" as explained in the Suppressing Warnings and Errors section.

ForegroundServiceType Correctness Error Priority 5/10

Replace usage of Switch widget

../../src/main/java/com/owncloud/android/ui/ThemeableSwitchPreference.java:57: Use SwitchCompat from AppCompat or MaterialSwitch from Material library

 54         for (int i = 0; i < viewGroup.getChildCount(); i++) {
 55             View child = viewGroup.getChildAt(i);
 56 
 57             if (child instanceof Switch switchView) {                                               
 58                 viewThemeUtils.platform.colorSwitch(switchView);
 59 
 60                 break;

Use SwitchCompat from AppCompat or MaterialSwitch from Material library
To suppress this error, use the issue id "UseSwitchCompatOrMaterialCode" as explained in the Suppressing Warnings and Errors section.

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseSwitchCompatOrMaterialCode Correctness Warning Priority 5/10

Launched Unsafe Intent

../../src/main/java/com/owncloud/android/ui/activity/FileDisplayActivity.java:619: This intent could be coming from an untrusted source. It is later launched by an unprotected component com.owncloud.android.ui.activity.FileDisplayActivity. You could either make the component com.owncloud.android.ui.activity.FileDisplayActivity protected; or sanitize this intent using androidx.core.content.IntentSanitizer.

  616 
  617     // Is called with the flag FLAG_ACTIVITY_SINGLE_TOP and set the new file and intent
  618     @Override
  619     protected void onNewIntent(Intent intent) {                                                     
  620         super.onNewIntent(intent);
  621         setIntent(intent);

../../src/main/java/com/owncloud/android/ui/activity/FileDisplayActivity.java:634

The unsafe intent is launched here.

  631             onOpenFileIntent(intent);
  632         } else if (RESTART.equals(intent.getAction())) {
  633             finish();
  634             startActivity(intent);                                                                  
  635         } else {
  636             // Verify the action and get the query
  637             if (Intent.ACTION_SEARCH.equals(intent.getAction())) {

UnsafeIntentLaunch Security Warning Priority 6/10

Allowing User Certificates

../../src/main/res/xml/network_security_config.xml:15: The Network Security Configuration allows the use of user certificates in the release version of your app

 12             <!-- Trust preinstalled CAs -->
 13             <certificates src="system"/>
 14             <!-- Additionally trust user added CAs -->
 15             <certificates src="user"/>                                                              
 16         </trust-anchors>
 17     </base-config>
 18 </network-security-config>

Allowing user certificates could allow eavesdroppers to intercept data sent by your app, which could impact the privacy of your users. Consider nesting your app's trust-anchors inside a <debug-overrides> element to make sure they are only available when android:debuggable is set to true.

More info:

To suppress this error, use the issue id "AcceptsUserCertificates" as explained in the Suppressing Warnings and Errors section.

AcceptsUserCertificates Security Warning Priority 5/10

Insecure Base Configuration

../../src/main/res/xml/network_security_config.xml:10: Insecure Base Configuration

  7   ~ SPDX-License-Identifier: AGPL-3.0-or-later OR GPL-2.0-only
  8 -->
  9 <network-security-config>
 10     <base-config cleartextTrafficPermitted="true">                                                  
 11         <trust-anchors>
 12             <!-- Trust preinstalled CAs -->
 13             <certificates src="system"/>

Permitting cleartext traffic could allow eavesdroppers to intercept data sent by your app, which impacts the privacy of your users. Consider only allowing encrypted traffic by setting the cleartextTrafficPermitted tag to false.

More info:

Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.
To suppress this error, use the issue id "InsecureBaseConfiguration" as explained in the Suppressing Warnings and Errors section.

InsecureBaseConfiguration Security Warning Priority 5/10

Invalidating All RecyclerView Data

../../src/main/java/com/owncloud/android/ui/adapter/ActivityAndVersionListAdapter.java:102: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

  99             }
 100         }
 101 
 102         notifyDataSetChanged();                                                                     
 103     }
 104 
 105     @NonNull

../../src/main/java/com/owncloud/android/ui/adapter/ActivityListAdapter.java:128: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 125                 values.add(activity);
 126             }
 127         }
 128         notifyDataSetChanged();                                                                     
 129     }
 130 
 131     @NonNull

../../src/main/java/com/nextcloud/client/etm/pages/EtmFileTransferFragment.kt:68: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

  65 
  66   fun setStatus(status: TransferManager.Status) {
  67       transfers = listOf(status.pending, status.running, status.completed).flatten().reversed()
  68       notifyDataSetChanged()                                                                  
  69   }
  70 
  71   override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {

../../src/main/java/com/nextcloud/client/etm/EtmMenuAdapter.kt:27: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 24     var pages: List<EtmMenuEntry> = listOf()
 25         set(value) {
 26             field = value
 27             notifyDataSetChanged()                                                                  
 28         }
 29 
 30     class PageViewHolder(view: View, onClick: (Int) -> Unit) : RecyclerView.ViewHolder(view) {

../../src/main/java/com/owncloud/android/ui/fragment/ExtendedListFragment.java:381: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 378 
 379             preferences.setGridColumns(mScale);
 380 
 381             getRecyclerView().getAdapter().notifyDataSetChanged();                                  
 382 
 383             return true;
 384         }

../../src/main/java/com/owncloud/android/ui/fragment/ExtendedListFragment.java:397: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 394             mScale = Math.max(minColumnSize, Math.min(mScale, maxColumnSize));
 395             Integer scaleInt = Math.round(mScale);
 396             gridLayoutManager.setSpanCount(scaleInt);
 397             mRecyclerView.getAdapter().notifyDataSetChanged();                                      
 398         }
 399     }

../../src/main/java/com/owncloud/android/ui/adapter/LocalFileListAdapter.java:367: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 364                 mFilesAll = new ArrayList<>();
 365                 mFilesAll.addAll(mFiles);
 366 
 367                 notifyDataSetChanged();                                                             
 368                 localFileListFragmentInterface.setLoading(false);
 369             });
 370         });

../../src/main/java/com/owncloud/android/ui/adapter/LocalFileListAdapter.java:382: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 379             mFiles = sortOrder.sortLocalFiles(mFiles);
 380 
 381             uiHandler.post(() -> {
 382                 notifyDataSetChanged();                                                             
 383                 localFileListFragmentInterface.setLoading(false);
 384             });
 385         });

../../src/main/java/com/owncloud/android/ui/adapter/LocalFileListAdapter.java:423: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 420             }
 421             mFiles = result;
 422         }
 423         notifyDataSetChanged();                                                                     
 424     }
 425 
 426     /**

../../src/main/java/com/owncloud/android/ui/adapter/LocalFileListAdapter.java:548: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 545         mFilesAll = new ArrayList<>();
 546         mFilesAll.addAll(mFiles);
 547 
 548         notifyDataSetChanged();                                                                     
 549         localFileListFragmentInterface.setLoading(false);
 550     }
 551 }

../../src/main/java/com/owncloud/android/ui/fragment/LocalFileListFragment.java:375: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 372   } else {
 373       // ugly hack because setEmptyListLoadingMessage also uses a handler and there's a race condition otherwise
 374       new Handler().post(() -> {
 375           mAdapter.notifyDataSetChanged();                                                    
 376           if (mAdapter.getFilesCount() == 0) {
 377               setEmptyListMessage(SearchType.LOCAL_SEARCH);
 378           }

../../src/main/java/com/nextcloud/client/logger/ui/LogsAdapter.kt:33: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 30     var entries: List<LogEntry> = listOf()
 31         set(value) {
 32             field = value
 33             notifyDataSetChanged()                                                                  
 34         }
 35 
 36     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) =

../../src/main/java/com/owncloud/android/ui/adapter/NotificationListAdapter.java:92: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

  89     public void setNotificationItems(List<Notification> notificationItems) {
  90         notificationsList.clear();
  91         notificationsList.addAll(notificationItems);
  92         notifyDataSetChanged();                                                                     
  93     }
  94 
  95     @NonNull

../../src/main/java/com/owncloud/android/ui/adapter/NotificationListAdapter.java:342: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 339 
 340     public void removeAllNotifications() {
 341         notificationsList.clear();
 342         notifyDataSetChanged();                                                                     
 343     }
 344

../../src/main/java/com/owncloud/android/ui/adapter/OCFileListAdapter.java:1107: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 1104     public void setSortOrder(@Nullable OCFile folder, FileSortOrder sortOrder) {
 1105         preferences.setSortOrder(folder, sortOrder);
 1106         mFiles = sortOrder.sortCloudFiles(mFiles);
 1107         notifyDataSetChanged();                                                                     
 1108 
 1109         this.sortOrder = sortOrder;
 1110     }

../../src/main/java/com/owncloud/android/ui/fragment/OCFileListFragment.java:1709: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 1706         getRecyclerView().scrollToPosition(position);
 1707         getAdapter().setGridView(grid);
 1708         getRecyclerView().setAdapter(getAdapter());
 1709         getAdapter().notifyDataSetChanged();                                                        
 1710     }
 1711 
 1712     public CommonOCFileListAdapterInterface getCommonAdapter() {

../../src/main/java/com/owncloud/android/ui/fragment/OCFileListSearchAsyncTask.kt:79: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 76         fragmentReference.get()?.let { fragment ->
 77             fragment.isLoading = false
 78             if (!isCancelled) {
 79                 fragment.adapter.notifyDataSetChanged()                                             
 80             }
 81         }
 82     }

../../src/main/java/com/owncloud/android/ui/adapter/RichDocumentsTemplateAdapter.java:84: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

  81 
  82     public void setTemplateAsActive(Template template) {
  83         selectedTemplate = template;
  84         notifyDataSetChanged();                                                                     
  85     }
  86 
  87     public Template getSelectedTemplate() {

../../src/main/java/com/nextcloud/ui/SetStatusDialogFragment.kt:439: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 436     @VisibleForTesting
 437     fun setPredefinedStatus(predefinedStatus: ArrayList<PredefinedStatus>) {
 438         adapter.list = predefinedStatus
 439         binding.predefinedStatusList.adapter?.notifyDataSetChanged()                                
 440     }
 441 }

../../src/main/java/com/owncloud/android/ui/adapter/TrashbinListAdapter.java:103: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 100       files = preferences.getSortOrderByType(FileSortOrder.Type.trashBinView,
 101                                              FileSortOrder.SORT_NEW_TO_OLD).sortTrashbinFiles(files);
 102 
 103       notifyDataSetChanged();                                                                     
 104   }
 105 
 106   @NonNull

../../src/main/java/com/owncloud/android/ui/adapter/TrashbinListAdapter.java:211: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 208 
 209     public void removeAllFiles() {
 210         files.clear();
 211         notifyDataSetChanged();                                                                     
 212     }
 213 
 214     private String getFooterText() {

../../src/main/java/com/owncloud/android/ui/adapter/TrashbinListAdapter.java:351: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 348     public void setSortOrder(FileSortOrder sortOrder) {
 349         preferences.setSortOrder(FileSortOrder.Type.trashBinView, sortOrder);
 350         files = sortOrder.sortTrashbinFiles(files);
 351         notifyDataSetChanged();                                                                     
 352     }
 353 
 354     @SuppressLint("NotifyDataSetChanged")

../../src/main/java/com/owncloud/android/ui/adapter/UploadListAdapter.java:870: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

  867             group.refresh();
  868         }
  869 
  870         notifyDataSetChanged();                                                                     
  871     }
  872 
  873     /**

../../src/main/java/com/owncloud/android/ui/activity/UserInfoActivity.java:378: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 375 
 376         public void setData(List<UserInfoDetailsItem> displayList) {
 377             mDisplayList = displayList == null ? new LinkedList<>() : displayList;
 378             notifyDataSetChanged();                                                                 
 379         }
 380 
 381         @NonNull

../../src/main/java/com/owncloud/android/ui/adapter/UserListAdapter.java:170: It will always be more efficient to use more specific change events if you can. Rely on notifyDataSetChanged as a last resort.

 167             values = new ArrayList<>();
 168         }
 169         values.addAll(items);
 170         notifyDataSetChanged();                                                                     
 171     }
 172 
 173     public interface Listener {

The RecyclerView adapter's onNotifyDataSetChanged method does not specify what about the data set has changed, forcing any observers to assume that all existing items and structure may no longer be valid. `LayoutManager`s will be forced to fully rebind and relayout all visible views.
To suppress this error, use the issue id "NotifyDataSetChanged" as explained in the Suppressing Warnings and Errors section.

NotifyDataSetChanged Performance Warning Priority 8/10

Static Field Leaks

../../src/main/java/com/owncloud/android/ui/activity/ErrorsWhileCopyingHandlerActivity.java:197: This AsyncTask class should be static or leaks might occur (com.owncloud.android.ui.activity.ErrorsWhileCopyingHandlerActivity.MoveFilesTask)

 194     /**
 195      * Asynchronous task performing the move of all the local files to the ownCloud folder.
 196      */
 197     private class MoveFilesTask extends AsyncTask<Void, Void, Boolean> {                            
 198 
 199         /**
 200          * Updates the UI before trying the movement

../../src/main/java/com/owncloud/android/ui/asynctasks/FetchRemoteFileTask.java:33: This field leaks a context object

  30     private final User user;
  31     private final String fileId;
  32     private final FileDataStorageManager storageManager;
  33     private final FileDisplayActivity fileDisplayActivity;                                          
  34     private OCFile ocFile;
  35 
  36     public FetchRemoteFileTask(User user,

../../src/main/java/com/owncloud/android/ui/activities/data/files/FilesServiceApiImpl.java:60: This field leaks a context object

  57         private final FilesServiceCallback<OCFile> callback;
  58         private OCFile remoteOcFile;
  59         private String errorMessage;
  60         // TODO: Figure out a better way to do this than passing a BaseActivity reference.          
  61         private final BaseActivity baseActivity;
  62         private final String fileUrl;
  63         private final User user;

../../src/main/java/com/nextcloud/client/logger/ui/LogsViewModel.kt:21: This field leaks a context object

  18 import javax.inject.Inject
  19 
  20 class LogsViewModel @Inject constructor(
  21     private val context: Context,                                                                   
  22     clock: Clock,
  23     asyncRunner: AsyncRunner,
  24     private val logsRepository: LogsRepository

../../src/main/java/com/owncloud/android/ui/activity/ManageSpaceActivity.kt:65: This AsyncTask class should be static or leaks might occur (com.owncloud.android.ui.activity.ManageSpaceActivity.ClearDataAsyncTask)

  62     /**
  63      * AsyncTask for Clear Data, saving the passcode
  64      */
  65     private inner class ClearDataAsyncTask : AsyncTask<Void, Void, Boolean>() {                     
  66         private val preferences = this@ManageSpaceActivity.preferences
  67         private val userAccountManager = this@ManageSpaceActivity.userAccountManager

../../src/main/java/com/owncloud/android/ui/asynctasks/NotificationExecuteActionTask.java:35: This field leaks a context object

 32    private final NotificationListAdapter.NotificationViewHolder holder;
 33    private final NextcloudClient client;
 34    private final Notification notification;
 35    private final NotificationsActivity notificationsActivity;                                      
 36 
 37    public NotificationExecuteActionTask(NextcloudClient client,
 38                                         NotificationListAdapter.NotificationViewHolder holder,

../../src/main/java/com/owncloud/android/ui/preview/PreviewTextFileFragment.java:149: This AsyncTask class should be static or leaks might occur (com.owncloud.android.ui.preview.PreviewTextFileFragment.TextLoadAsyncTask)

 146     /**
 147      * Reads the file to preview and shows its contents. Too critical to be anonymous.
 148      */
 149     private class TextLoadAsyncTask extends AsyncTask<Object, Void, StringWriter> {                 
 150         private static final int PARAMS_LENGTH = 1;
 151         private final WeakReference<TextView> textViewReference;
 152         private final WeakReference<FrameLayout> progressViewReference;

../../src/main/java/com/owncloud/android/ui/activity/StorageMigration.java:183: This field leaks a context object

 180   private static abstract class FileMigrationTaskBase extends AsyncTask<Void, Integer, Integer> {
 181       protected String mStorageSource;
 182       protected String mStorageTarget;
 183       protected Context mContext;                                                                 
 184       protected User user;
 185       protected ProgressDialog mProgressDialog;
 186       protected StorageMigrationProgressListener mListener;

../../src/main/java/com/owncloud/android/datamodel/ThumbnailsCacheManager.java:827: This field leaks a context object

  824         private final WeakReference<ImageView> mImageViewReference;
  825         private File mFile;
  826         private String mImageKey;
  827         private final Context mContext;                                                             
  828         private final ViewThemeUtils viewThemeUtils;
  829 
  830         public MediaThumbnailGenerationTask(ImageView imageView,

../../src/main/java/com/owncloud/android/datamodel/ThumbnailsCacheManager.java:966: This field leaks a context object

  963         private final String mUserId;
  964         private final String displayName;
  965         private final String mServerName;
  966         private final Context mContext;                                                             
  967 
  968 
  969         public AvatarGenerationTask(AvatarGenerationListener avatarGenerationListener,

A static field will leak contexts.

Non-static inner classes have an implicit reference to their outer class. If that outer class is for example a Fragment or Activity, then this reference means that the long-running handler/loader/task will hold a reference to the activity which prevents it from getting garbage collected.

Similarly, direct field references to activities and fragments from these longer running instances can cause leaks.

ViewModel classes should never point to Views or non-application Contexts.
To suppress this error, use the issue id "StaticFieldLeak" as explained in the Suppressing Warnings and Errors section.

StaticFieldLeak Performance Warning Priority 6/10

Nested layout weights

../../src/main/res/layout/first_run_activity.xml:27: Nested weights are bad for performance

 24             android:id="@+id/contentPanel"
 25             android:layout_width="match_parent"
 26             android:layout_height="0dp"
 27             android:layout_weight="1"/>                                                             
 28 
 29         <com.owncloud.android.ui.whatsnew.ProgressIndicator
 30             android:id="@+id/progressIndicator"

../../src/main/res/layout/whats_new_activity.xml:50: Nested weights are bad for performance

 47             android:layout_width="0dp"
 48             android:layout_height="match_parent"
 49             android:layout_gravity="center_vertical|center_horizontal"
 50             android:layout_weight="1"                                                               
 51             android:gravity="center"
 52             android:paddingLeft="0dp"
 53             android:paddingRight="0dp"

Layout weights require a widget to be measured twice. When a LinearLayout with non-zero weights is nested inside another LinearLayout with non-zero weights, then the number of measurements increase exponentially.
To suppress this error, use the issue id "NestedWeights" as explained in the Suppressing Warnings and Errors section.

NestedWeights Performance Warning Priority 3/10

Overdraw: Painting regions more than once

../../src/main/res/layout/activity_edit_image.xml:13: Possible overdraw: Root element paints background @color/black with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

 10     xmlns:app="http://schemas.android.com/apk/res-auto"
 11     android:layout_width="match_parent"
 12     android:layout_height="match_parent"
 13     android:background="@color/black">                                                              
 14 
 15     <androidx.appcompat.widget.Toolbar
 16         android:id="@+id/toolbar"

../../src/main/res/layout/activity_row.xml:12: Possible overdraw: Root element paints background ?android:attr/activatedBackgroundIndicator with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

  9     android:id="@+id/list_item"
 10     android:layout_width="match_parent"
 11     android:layout_height="@dimen/activity_row_layout_height"
 12     android:background="?android:attr/activatedBackgroundIndicator"                                    
 13     android:minWidth="@dimen/activity_row_layout_min_width_independent"
 14     android:orientation="horizontal"
 15     android:paddingEnd="@dimen/standard_padding"

../../src/main/res/layout/activity_splash.xml:12: Possible overdraw: Root element paints background @color/primary with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

  9     xmlns:app="http://schemas.android.com/apk/res-auto"
 10     android:layout_width="match_parent"
 11     android:layout_height="match_parent"
 12     android:background="@color/primary">                                                            
 13 
 14     <androidx.appcompat.widget.AppCompatImageView
 15         android:id="@+id/ivSplash"

../../src/main/res/layout/dialog_preview_video.xml:15: Possible overdraw: Root element paints background @color/black with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

 12     android:layout_width="match_parent"
 13     android:layout_height="match_parent"
 14     android:layout_gravity="center"
 15     android:background="@color/black"                                                               
 16     app:show_buffering="always" />

../../src/main/res/layout/drawer_header.xml:15: Possible overdraw: Root element paints background @color/primary with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

  12     android:id="@+id/drawer_header_view"
  13     android:layout_width="match_parent"
  14     android:layout_height="wrap_content"
  15     android:background="@color/primary"                                                             
  16     android:gravity="center"
  17     android:orientation="vertical">

../../src/main/res/layout/file_details_sharing_menu_bottom_sheet_fragment.xml:17: Possible overdraw: Root element paints background @color/bg_default with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

  14     android:layout_height="wrap_content"
  15     android:orientation="vertical"
  16     android:paddingTop="@dimen/dialog_padding"
  17     android:background="@color/bg_default">                                                         
  18 
  19     <LinearLayout
  20         android:id="@+id/menu_share_advanced_permissions"

../../src/main/res/layout/generic_explanation.xml:15: Possible overdraw: Root element paints background @color/bg_default with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

 12     android:id="@+id/explanation"
 13     android:layout_width="match_parent"
 14     android:layout_height="match_parent"
 15     android:background="@color/bg_default"                                                          
 16     android:orientation="vertical">
 17 
 18     <TextView

../../src/main/res/layout/info_box.xml:15: Possible overdraw: Root element paints background @color/filelist_icon_background with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

 12     android:layout_width="match_parent"
 13     android:layout_height="wrap_content"
 14     android:layout_gravity="center_horizontal|bottom"
 15     android:background="@color/filelist_icon_background"                                            
 16     android:gravity="center"
 17     android:padding="@dimen/standard_half_padding"
 18     android:visibility="gone">

../../src/main/res/layout/item_quick_share_permissions.xml:13: Possible overdraw: Root element paints background ?android:attr/selectableItemBackground with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

 10     xmlns:app="http://schemas.android.com/apk/res-auto"
 11     android:layout_width="match_parent"
 12     android:layout_height="@dimen/bottom_sheet_item_height"
 13     android:background="?android:attr/selectableItemBackground"                                     
 14     android:paddingStart="@dimen/standard_padding"
 15     android:paddingEnd="@dimen/standard_padding">

../../src/main/res/layout/toolbar_standard.xml:16: Possible overdraw: Root element paints background @color/bg_default with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

  13     android:id="@+id/appbar"
  14     android:layout_width="match_parent"
  15     android:layout_height="wrap_content"
  16     android:background="@color/bg_default">                                                         
  17 
  18     <FrameLayout
  19         android:layout_width="match_parent"

../../src/main/res/layout/user_info_layout.xml:14: Possible overdraw: Root element paints background @color/bg_default with a theme that also paints a background (inferred theme is @style/Theme.ownCloud.Toolbar)

  11     xmlns:tools="http://schemas.android.com/tools"
  12     android:layout_width="match_parent"
  13     android:layout_height="match_parent"
  14     android:background="@color/bg_default"                                                          
  15     android:orientation="vertical">
  16 
  17     <include layout="@layout/toolbar_standard" />

Overdraw Performance Warning Priority 3/10

Using getUsableSpace()

../../src/main/java/com/owncloud/android/utils/FileStorageUtils.java:142: Consider also using StorageManager#getAllocatableBytes and allocateBytes which will consider clearable cached data

 139      */
 140     public static long getUsableSpace() {
 141         File savePath = new File(MainApp.getStoragePath());
 142         return savePath.getUsableSpace();                                                           
 143     }
 144 
 145     /**

When you need to allocate disk space for large files, consider using the new allocateBytes(FileDescriptor, long) API, which will automatically clear cached files belonging to other apps (as needed) to meet your request.

When deciding if the device has enough disk space to hold your new data, call getAllocatableBytes(UUID) instead of using getUsableSpace(), since the former will consider any cached data that the system is willing to clear on your behalf.

Note that these methods require API level 26. If your app is running on older devices, you will probably need to use both APIs, conditionally switching on Build.VERSION.SDK_INT. Lint only looks in the same compilation unit to see if you are already using both APIs, so if it warns even though you are already using the new API, consider moving the calls to the same file or suppressing the warning.
To suppress this error, use the issue id "UsableSpace" as explained in the Suppressing Warnings and Errors section.

UsableSpace Performance Warning Priority 3/10

Accessibility in Custom Views

../../src/main/java/com/owncloud/android/ui/fragment/ExtendedListFragment.java:341: Custom view `RecyclerView` has setOnTouchListener called on it but does not override performClick

 338 
 339   mScaleGestureDetector = new ScaleGestureDetector(MainApp.getAppContext(), new ScaleListener());
 340 
 341   getRecyclerView().setOnTouchListener((view, motionEvent) -> {                               
 342       mScaleGestureDetector.onTouchEvent(motionEvent);
 343 
 344       if (motionEvent.getAction() == MotionEvent.ACTION_UP) {

If a View that overrides onTouchEvent or uses an OnTouchListener does not also implement performClick and call it when clicks are detected, the View may not handle accessibility actions properly. Logic handling the click actions should ideally be placed in View#performClick as some accessibility services invoke performClick when a click action should occur.
To suppress this error, use the issue id "ClickableViewAccessibility" as explained in the Suppressing Warnings and Errors section.

ClickableViewAccessibility Accessibility Warning Priority 6/10

Included Additional Checks

This card lists all the extra checks run by lint, provided from libraries, build configuration and extra flags. This is included to help you verify whether a particular check is included in analysis when configuring builds. (Note that the list does not include the hundreds of built-in checks into lint, only additional ones.)

ArcAnimationSpecTypeIssue

ArcAnimationSpec is designed for 2D values. Particularly, for positional values such as Offset.
Trying to use it for values of different dimensions (Float, Size, Color, etc.) will result in unpredictable animation behavior.

Vendor: Jetpack Compose
Identifier: androidx.compose.animation.core
Feedback: https://issuetracker.google.com/issues/new?component=612128

AutoboxingStateCreation

Calling mutableStateOf<T>() when T is either backed by a primitive type on the JVM or is a value class results in a state implementation that requires all state values to be boxed. This usually causes an additional allocation for each state write, and adds some additional work to auto-unbox values when reading the value of the state. Instead, prefer to use a specialized primitive state implementation for Int, Long, Float, and Double when the state does not need to track null values and does not override the default SnapshotMutationPolicy. See mutableIntStateOf(), mutableLongStateOf(), mutableFloatStateOf(), and mutableDoubleStateOf() for more information.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

AutoboxingStateValueProperty

Avoid using the generic value property when using a specialized State type. Reading or writing to the state's generic value property will result in an unnecessary autoboxing operation. Prefer the specialized value property (e.g. intValue for MutableIntState), or use property delegation to avoid unnecessary allocations.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

BadConfigurationProvider

An android.app.Application must implement androidx.work.Configuration.Provider
for on-demand initialization.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

BadPeriodicWorkRequestEnqueue

When using enqueue() for `PeriodicWorkRequest`s, you might end up enqueuing
duplicate requests unintentionally. You should be using
enqueueUniquePeriodicWork with an ExistingPeriodicWorkPolicy.KEEP instead.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

ComposableNaming

@Composable functions without a return type should use similar naming to classes, starting with an uppercase letter and ending with a noun. @Composable functions with a return type should be treated as normal Kotlin functions, starting with a lowercase letter.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

CompositionLocalNaming

CompositionLocal properties should be prefixed with Local. This helps make it clear at their use site that these values are local to the current composition. Typically the full name will be Local + the type of the CompositionLocal, for example val LocalFoo = compositionLocalOf { Foo() }.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

ConflictingOnColor

In the Material color system background colors have a corresponding 'on' color which is used for the content color inside a component. For example, a button colored primary will have onPrimary text. Because of this, it is important that there is only one possible onColor for a given color value, otherwise there is no way to know which 'on' color should be used inside a component. To fix this either use the same 'on' color for identical background colors, or use a different background color for each 'on' color.

Vendor: Jetpack Compose
Identifier: androidx.compose.material
Feedback: https://issuetracker.google.com/issues/new?component=612128

CoroutineCreationDuringComposition

Creating a coroutine with async or launch during composition is often incorrect - this means that a coroutine will be created even if the composition fails / is rolled back, and it also means that multiple coroutines could end up mutating the same state, causing inconsistent results. Instead, use LaunchedEffect and create coroutines inside the suspending block. The block will only run after a successful composition, and will cancel existing coroutines when key changes, allowing correct cleanup.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

DetachAndAttachSameFragment

When doing a FragmentTransaction that includes both attach() and detach() operations being committed on the same fragment instance, it is a no-op. The reason for this is that the FragmentManager optimizes all operations within a single transaction so the attach() and detach() cancel each other out and neither is actually executed. To get the desired behavior, you should separate the attach() and detach() calls into separate FragmentTransactions.

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

DialogFragmentCallbacksDetector

When using a DialogFragment, the setOnCancelListener and setOnDismissListener callback functions within the onCreateDialog function __must not be used__ because the DialogFragment owns these callbacks. Instead the respective onCancel and onDismiss functions can be used to achieve the desired effect.

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

EnsureInitializerMetadata

When a library defines a Initializer, it needs to be accompanied by a corresponding <meta-data> entry in the AndroidManifest.xml file.

Vendor: Android Open Source Project
Identifier: androidx.startup
Feedback: https://issuetracker.google.com/issues/new?component=823348

EnsureInitializerNoArgConstr

Every Initializer must have a no argument constructor.

Vendor: Android Open Source Project
Identifier: androidx.startup
Feedback: https://issuetracker.google.com/issues/new?component=823348

ExperimentalAnnotationRetention

Experimental annotations defined in Java source should use default (CLASS) retention, while Kotlin-sourced annotations should use BINARY retention.

Vendor: Android Open Source Project
Identifier: androidx.annotation.experimental
Feedback: https://issuetracker.google.com/issues/new?component=459778

FieldSiteTargetOnQualifierAnnotation

It's redundant to use 'field:' site-targets for qualifier annotations.

Vendor: Google
Identifier: com.google.dagger:dagger-lint
Contact: https://github.com/google/dagger
Feedback: https://github.com/google/dagger/issues

FlowOperatorInvokedInComposition

Calling a Flow operator function within composition will result in a new Flow being created every recomposition, which will reset collectAsState() and cause other related problems. Instead Flow operators should be called inside remember, or a side effect such as LaunchedEffect.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

FragmentAddMenuProvider

The Fragment lifecycle can result in a Fragment being active longer than its view. This can lead to unexpected behavior from lifecycle aware objects remaining active longer than the Fragment's view. To solve this issue, getViewLifecycleOwner() should be used as a LifecycleOwner rather than the Fragment instance once it is safe to access the view lifecycle in a Fragment's onCreateView, onViewCreated, onActivityCreated, or onViewStateRestored methods.

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

FragmentBackPressedCallback

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

FragmentLiveDataObserve

When observing a LiveData object from a fragment's onCreateView, onViewCreated, onActivityCreated, or onViewStateRestored method getViewLifecycleOwner() should be used as the LifecycleOwner rather than the Fragment instance. The Fragment lifecycle can result in the Fragment being active longer than its view. This can lead to unexpected behavior from LiveData objects being observed longer than the Fragment's view is active.

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

FragmentTagUsage

FragmentContainerView replaces the <fragment> tag as the preferred way of adding fragments via XML. Unlike the <fragment> tag, FragmentContainerView uses a normal FragmentTransaction under the hood to add the initial fragment, allowing further FragmentTransaction operations on the FragmentContainerView and providing a consistent timing for lifecycle events.

More info: https://developer.android.com/reference/androidx/fragment/app/FragmentContainerView.html

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

FrequentlyChangedStateReadInComposition

This property is observable and is updated after every scroll or remeasure. If you use it in the composable function directly, it will be recomposed on every change, causing potential performance issues including infinity recomposition loops. Prefer wrapping it with derivedStateOf to use calculation based on this property in composition or collect changes inside LaunchedEffect instead.

Vendor: Jetpack Compose
Identifier: androidx.compose.foundation
Feedback: https://issuetracker.google.com/issues/new?component=612128

IdleBatteryChargingConstraints

Some devices are never considered charging and idle at the same time.
Consider removing one of these constraints.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

InvalidColorHexValue

Vendor: Jetpack Compose
Identifier: androidx.compose.ui.graphics
Feedback: https://issuetracker.google.com/issues/new?component=612128

InvalidFragmentVersionForActivityResult

In order to use the ActivityResult APIs you must upgrade your Fragment version to 1.3.0. Previous versions of FragmentActivity failed to call super.onRequestPermissionsResult() and used invalid request codes

More info: https://developer.android.com/training/permissions/requesting#make-the-request

Vendor: Android Open Source Project
Identifier: androidx.activity
Feedback: https://issuetracker.google.com/issues/new?component=527362

InvalidLanguageTagDelimiter

A language tag must be compliant with IETF BCP47, specifically a sequence of subtags must be separated by hyphens (-) instead of underscores (_)

Vendor: Jetpack Compose
Identifier: androidx.compose.ui.text
Feedback: https://issuetracker.google.com/issues/new?component=779818

InvalidPeriodicWorkRequestInterval

The interval duration for a PeriodicWorkRequest must be at least 15 minutes.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

InvalidSetHasFixedSize

When a RecyclerView uses setHasFixedSize(...) you cannot use wrap_content for size in the scrolling direction.

Vendor: Android Open Source Project
Identifier: androidx.recyclerview
Feedback: https://issuetracker.google.com/issues/new?component=460887

InvalidUseOfOnBackPressed

You should not used OnBackPressedCallback for non-UI cases. If you
|add a callback, you have to handle back completely in the callback.

More info: https://developer.android.com/guide/navigation/custom-back/predictive-back-gesture#ui-logic

Vendor: Android Open Source Project
Identifier: androidx.activity
Feedback: https://issuetracker.google.com/issues/new?component=527362

JvmStaticProvidesInObjectDetector

It's redundant to annotate @Provides functions in object classes with @JvmStatic.

Vendor: Google
Identifier: com.google.dagger:dagger-lint
Contact: https://github.com/google/dagger
Feedback: https://github.com/google/dagger/issues

LaunchDuringComposition

Calling launch during composition is incorrect. Doing so will cause launch to be called multiple times resulting in a RuntimeException. Instead, use SideEffect and launch inside of the suspending block. The block will only run after a successful composition.

Vendor: Jetpack Activity Compose
Identifier: androidx.activity.compose
Feedback: https://issuetracker.google.com/issues/new?component=612128

MissingColorAlphaChannel

Creating a Color with a hex value requires a 32 bit value (such as 0xFF000000), with 8 bits being used per channel (ARGB). Not passing a full 32 bit value will result in channels being undefined. For example, passing 0xFF0000 will result in a missing alpha channel, so the color will not appear visible.

Vendor: Jetpack Compose
Identifier: androidx.compose.ui.graphics
Feedback: https://issuetracker.google.com/issues/new?component=612128

ModifierFactoryExtensionFunction

Modifier factory functions should be defined as extension functions on Modifier to allow modifiers to be fluently chained.

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

ModifierFactoryReturnType

Modifier factory functions should return Modifier as their type, and not a subtype of Modifier (such as Modifier.Element).

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

ModifierFactoryUnreferencedReceiver

Modifier factory functions are fluently chained to construct a chain of Modifier objects that will be applied to a layout. As a result, each factory function must use the receiver Modifier parameter, to ensure that the function is returning a chain that includes previous items in the chain. Make sure the returned chain either explicitly includes this, such as return this.then(MyModifier) or implicitly by returning a chain that starts with an implicit call to another factory function, such as return myModifier(), where myModifier is defined as fun Modifier.myModifier(): Modifier.

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

ModifierNodeInspectableProperties

ModifierNodeElements may override inspectableProperties() to provide information about the modifier in the layout inspector. The default implementation attempts to read all of the properties on the class reflectively, which may not comprehensively or effectively describe the modifier.

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

ModifierParameter

The first (or only) Modifier parameter in a Composable function should follow the following rules:
- Be named modifier
- Have a type of Modifier
- Either have no default value, or have a default value of Modifier
- If optional, be the first optional parameter in the parameter list

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

ModuleCompanionObjects

Companion objects in @Module-annotated classes are considered part of the API.

Vendor: Google
Identifier: com.google.dagger:dagger-lint
Contact: https://github.com/google/dagger
Feedback: https://github.com/google/dagger/issues

ModuleCompanionObjectsNotInModuleParent

Companion objects in @Module-annotated classes are considered part of the API. This
companion object is not a companion to an @Module-annotated class though, and should be
moved to a top-level object declaration instead otherwise Dagger will ignore companion
object.

Vendor: Google
Identifier: com.google.dagger:dagger-lint
Contact: https://github.com/google/dagger
Feedback: https://github.com/google/dagger/issues

MultipleAwaitPointerEventScopes

Pointer Input events are queued inside awaitPointerEventScope. Multiple calls to awaitPointerEventScope may exit the scope. During this time there is no guarantee that the events will be queued and some events may be dropped. It is recommended to use a single top-level block and perform the pointer events processing within such block.

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

MutableCollectionMutableState

Writes to mutable collections inside a MutableState will not cause a recomposition - only writes to the MutableState itself will. In most cases you should either use a read-only collection (such as List or Map) and assign a new instance to the MutableState when your data changes, or you can use an snapshot-backed collection such as SnapshotStateList or SnapshotStateMap which will correctly cause a recomposition when their contents are modified.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

NoCollectCallFound

You must call collect on the progress in the onBack function. The collect call is what properly splits the callback so it knows what to do when the back gestures is started vs when it is completed. Failing to call collect will cause all code in the block to run when the gesture is started.

Vendor: Jetpack Activity Compose
Identifier: androidx.activity.compose
Feedback: https://issuetracker.google.com/issues/new?component=612128

NullSafeMutableLiveData

This check ensures that LiveData values are not null when explicitly declared as non-nullable.

Kotlin interoperability does not support enforcing explicit null-safety when using generic Java type parameters. Since LiveData is a Java class its value can always be null even when its type is explicitly declared as non-nullable. This can lead to runtime exceptions from reading a null LiveData value that is assumed to be non-nullable.

Vendor: Android Open Source Project
Identifier: androidx.lifecycle
Feedback: https://issuetracker.google.com/issues/new?component=413132

OpaqueUnitKey

Certain Compose functions including remember, LaunchedEffect, and DisposableEffect declare (and sometimes require) one or more key parameters. When a key parameter changes, it is a signal that the previous invocation is now invalid. In certain cases, it may be required to pass Unit as a key to one of these functions, indicating that the invocation never becomes invalid. Using Unit as a key should be done infrequently, and should always be done explicitly by passing the Unit literal. This inspection checks for invocations where Unit is being passed as a key argument in any form other than the Unit literal. This is usually done by mistake, and can harm readability. If a Unit expression is being passed as a key, it is always equivalent to move the expression before the function invocation and pass the Unit literal instead.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

ProduceStateDoesNotAssignValue

produceState returns an observable State using values assigned inside the producer lambda. If the lambda never assigns (i.e value = foo), then the State will never change. Make sure to assign a value when the source you are producing values from changes / emits a new value. For sample usage see the produceState documentation.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

RememberReturnType

A call to remember that returns Unit is always an error. This typically happens when using remember to mutate variables on an object. remember is executed during the composition, which means that if the composition fails or is happening on a separate thread, the mutated variables may not reflect the true state of the composition. Instead, use SideEffect to make deferred changes once the composition succeeds, or mutate MutableState backed variables directly, as these will handle composition failure for you.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

RememberSaveableSaverParameter

The first parameter to rememberSaveable is a vararg parameter for inputs that when changed will cause the state to reset. Passing a Saver object to this parameter is an error, as the intention is to pass the Saver object to the saver parameter. Since the saver parameter is not the first parameter, it must be explicitly named.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime.saveable
Feedback: https://issuetracker.google.com/issues/new?component=612128

RemoveWorkManagerInitializer

If an android.app.Application implements androidx.work.Configuration.Provider,
the default androidx.startup.InitializationProvider needs to be removed from the
AndroidManifest.xml file.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

RepeatOnLifecycleWrongUsage

The repeatOnLifecycle APIs should be used when the View is created, that is in the onCreate lifecycle method for Activities, or onViewCreated in case you're using Fragments.

Vendor: Android Open Source Project
Identifier: androidx.lifecycle
Feedback: https://issuetracker.google.com/issues/new?component=413132

ReturnFromAwaitPointerEventScope

Pointer Input events are queued inside awaitPointerEventScope. By using the return value of awaitPointerEventScope one might unexpectedly lose events. If another awaitPointerEventScope is restarted there is no guarantee that the events will persist between those calls. In this case you should keep all events inside the awaitPointerEventScope block

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

SpecifyForegroundServiceType

When using the setForegroundAsync() API, the application must override <service /> entry for SystemForegroundService to include the foreground service type in the AndroidManifest.xml file.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

SpecifyJobSchedulerIdRange

When using JobScheduler APIs directly, WorkManager requires that developers specify a range of JobScheduler ids that are safe for WorkManager to use so the `id`s do not collide.
For more information look at androidx.work.Configuration.Builder.setJobSchedulerJobIdRange(int, int).

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

StateFlowValueCalledInComposition

Calling StateFlow.value within composition will not observe changes to the StateFlow, so changes might not be reflected within the composition. Instead you should use stateFlow.collectAsState() to observe changes to the StateFlow, and recompose when it changes.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

SuspiciousCompositionLocalModifierRead

Jetpack Compose is unable to send updated values of a CompositionLocal when it's read in a Modifier.Node's initializer and onAttach() or onDetach() callbacks. Modifier.Node's callbacks are not aware of snapshot reads, and their lifecycle callbacks are not invoked on every recomposition. If you read a CompositionLocal in onAttach() or onDetach(), you will only get the CompositionLocal's value once at the moment of the read, which may lead to unexpected behaviors. We recommend instead reading CompositionLocals at time-of-use in callbacks that apply your Modifier's behavior, like measure() for LayoutModifierNode, draw() for DrawModifierNode, and so on. To observe the value of the CompositionLocal manually, extend from the ObserverNode interface and place the read inside an observeReads {} block within the onObservedReadsChanged() callback.

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

SuspiciousModifierThen

Calling a Modifier factory function with an implicit receiver inside Modifier.then will result in the receiver (this) being added twice to the chain. For example, fun Modifier.myModifier() = this.then(otherModifier()) - the implementation of factory functions such as Modifier.otherModifier() will internally call this.then(...) to chain the provided modifier with their implementation. When you expand this.then(otherModifier()), it becomes: this.then(this.then(OtherModifierImplementation)) - so you can see that this is included twice in the chain, which results in modifiers such as padding being applied twice, for example. Instead, you should either remove the then() and directly chain the factory function on the receiver, this.otherModifier(), or add the empty Modifier as the receiver for the factory, such as this.then(Modifier.otherModifier())

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnnecessaryComposedModifier

Modifier.composed allows invoking @Composable functions when creating a Modifier instance - for example, using remember to have instance-specific state, allowing the same Modifier object to be safely used in multiple places. Using Modifier.composed without calling any @Composable functions inside is unnecessary, and since the Modifier is no longer skippable, this can cause a lot of extra work inside the composed body, leading to worse performance.

Vendor: Jetpack Compose
Identifier: androidx.compose.ui
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnrememberedAnimatable

Animatable instances created during composition need to be `remember`ed, otherwise they will be recreated during recomposition, and lose their state. Either hoist the Animatable to an object that is not created during composition, or wrap the Animatable in a call to remember.

Vendor: Jetpack Compose
Identifier: androidx.compose.animation.core
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnrememberedMutableInteractionSource

MutableInteractionSource instances created during composition need to be `remember`ed, otherwise they will be recreated during recomposition, and lose their state. Either hoist the MutableInteractionSource to an object that is not created during composition, or wrap the MutableInteractionSource in a call to remember.

Vendor: Jetpack Compose
Identifier: androidx.compose.foundation
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnrememberedMutableState

State objects created during composition need to be `remember`ed, otherwise they will be recreated during recomposition, and lose their state. Either hoist the state to an object that is not created during composition, or wrap the state in a call to remember.

Vendor: Jetpack Compose
Identifier: androidx.compose.runtime
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnsafeLifecycleWhenUsage

If the Lifecycle is destroyed within the block of Lifecycle.whenStarted or any similar Lifecycle.when method is suspended, the block will be cancelled, which will also cancel any child coroutine launched inside the block. As as a result, If you have a try finally block in your code, the finally might run after the Lifecycle moves outside the desired state. It is recommended to check the Lifecycle.isAtLeast before accessing UI in finally block. Similarly, if you have a catch statement that might catch CancellationException, you should check the Lifecycle.isAtLeast before accessing the UI. See documentation of Lifecycle.whenStateAtLeast for more details

Vendor: Android Open Source Project
Identifier: androidx.lifecycle
Feedback: https://issuetracker.google.com/issues/new?component=413132

UnsafeOptInUsageError

This API has been flagged as opt-in with error-level severity.

Any declaration annotated with this marker is considered part of an unstable or
otherwise non-standard API surface and its call sites should accept the opt-in
aspect of it by using the @OptIn annotation, using the marker annotation --
effectively causing further propagation of the opt-in aspect -- or configuring
the UnsafeOptInUsageError check's options for project-wide opt-in.

To configure project-wide opt-in, specify the opt-in option value in lint.xml
as a comma-delimited list of opted-in annotations:

<lint>
    <issue id="UnsafeOptInUsageError">
        <option name="opt-in" value="com.foo.ExperimentalBarAnnotation" />
    </issue>
</lint>

Vendor: Android Open Source Project
Identifier: androidx.annotation.experimental
Feedback: https://issuetracker.google.com/issues/new?component=459778

UnsafeOptInUsageWarning

This API has been flagged as opt-in with warning-level severity.

Any declaration annotated with this marker is considered part of an unstable or
otherwise non-standard API surface and its call sites should accept the opt-in
aspect of it by using the @OptIn annotation, using the marker annotation --
effectively causing further propagation of the opt-in aspect -- or configuring
the UnsafeOptInUsageWarning check's options for project-wide opt-in.

To configure project-wide opt-in, specify the opt-in option value in lint.xml
as a comma-delimited list of opted-in annotations:

<lint>
    <issue id="UnsafeOptInUsageWarning">
        <option name="opt-in" value="com.foo.ExperimentalBarAnnotation" />
    </issue>
</lint>

Vendor: Android Open Source Project
Identifier: androidx.annotation.experimental
Feedback: https://issuetracker.google.com/issues/new?component=459778

UnsafeRepeatOnLifecycleDetector

The repeatOnLifecycle APIs should be used with the viewLifecycleOwner in Fragments as opposed to lifecycleOwner.

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

UnusedBoxWithConstraintsScope

The content lambda in BoxWithConstraints has a scope which will include the incoming constraints. If this scope is ignored, then the cost of subcomposition is being wasted and this BoxWithConstraints should be replaced with a Box.

Vendor: Jetpack Compose
Identifier: androidx.compose.foundation
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnusedContentLambdaTargetStateParameter

content lambda in AnimatedContent works as a lookup function that returns the corresponding content based on the parameter (a state of type T). It is important for this lambda to return content specific to the input parameter, so that the different contents can be properly animated. Not using the input parameter to the content lambda will result in the same content for different input (i.e. target state) and therefore an erroneous transition between the exact same content.`

Vendor: Jetpack Compose
Identifier: androidx.compose.animation
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnusedCrossfadeTargetStateParameter

content lambda in Crossfade works as a lookup function that returns the corresponding content based on the parameter (a state of type T). It is important for this lambda to return content specific to the input parameter, so that the different contents can be properly crossfaded. Not using the input parameter to the content lambda will result in the same content for different input (i.e. target state) and therefore an erroneous crossfade between the exact same content.`

Vendor: Jetpack Compose
Identifier: androidx.compose.animation
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnusedMaterial3ScaffoldPaddingParameter

The content lambda in Scaffold has a padding parameter which will include any inner padding for the content due to app bars. If this parameter is ignored, then content may be obscured by the app bars resulting in visual issues or elements that can't be interacted with.

Vendor: Jetpack Compose
Identifier: androidx.compose.material3
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnusedMaterialScaffoldPaddingParameter

Vendor: Jetpack Compose
Identifier: androidx.compose.material
Feedback: https://issuetracker.google.com/issues/new?component=612128

UnusedTransitionTargetStateParameter

Transition.animate* functions provide a target state parameter in the lambda that will be used to calculate the value for a given state. This target state parameter in the lambda may or may not be the same as the actual state, as the animation system occasionally needs to look up target values for other states to do proper seeking/tooling preview. Relying on other state than the provided targetState could also result in unnecessary recompositions. Therefore, it is generally considered an error if this targetState parameter is not used.

Vendor: Jetpack Compose
Identifier: androidx.compose.animation.core
Feedback: https://issuetracker.google.com/issues/new?component=612128

UseAndroidAlpha

ColorStateList uses app:alpha without android:alpha

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseAppTint

ImageView or ImageButton uses android:tint instead of app:tint

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseCompatLoadingForColorStateLists

Use Compat loading of color state lists

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseCompatLoadingForDrawables

Use Compat loading of drawables

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseCompatTextViewDrawableApis

Use Compat loading of compound text view drawables

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseCompatTextViewDrawableXml

TextView uses android: compound drawable attributes instead of app: ones

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseGetLayoutInflater

Using LayoutInflater.from(Context) can return a LayoutInflater that does not have the correct theme.

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

UseOfNonLambdaOffsetOverload

Modifier.offset() is recommended to be used with static arguments only to avoid unnecessary recompositions. Modifier.offset{ } is preferred in the cases where the arguments are backed by a State.

Vendor: Jetpack Compose
Identifier: androidx.compose.foundation
Feedback: https://issuetracker.google.com/issues/new?component=612128

UseRequireInsteadOfGet

AndroidX added new "require____()" versions of common "get___()" APIs, such as getContext/getActivity/getArguments/etc. Rather than wrap these in something like requireNotNull(), using these APIs will allow the underlying component to try to tell you _why_ it was null, and thus yield a better error message.

Vendor: Android Open Source Project
Identifier: androidx.fragment
Feedback: https://issuetracker.google.com/issues/new?component=460964

UseRxSetProgress2

Use setCompletableProgress(...) instead of `setProgress(...) in RxWorker.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

UseSupportActionBar

Use AppCompatActivity.setSupportActionBar

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseSwitchCompatOrMaterialCode

Use SwitchCompat from AppCompat or MaterialSwitch from Material library

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UseSwitchCompatOrMaterialXml

Use SwitchCompat from AppCompat or MaterialSwitch from Material library

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

UsingMaterialAndMaterial3Libraries

material and material3 are separate design system libraries that are incompatible with each other, as they have their own distinct theming systems. Using components from both libraries concurrently can cause issues: for example material components will not pick up the correct content color from a material3 container, and vice versa.

Vendor: Jetpack Compose
Identifier: androidx.compose.material3
Feedback: https://issuetracker.google.com/issues/new?component=612128

UsingOnClickInXml

Old versions of the platform do not properly support resolving android:onClick

Vendor: Android Open Source Project
Identifier: androidx.appcompat
Feedback: https://issuetracker.google.com/issues/new?component=460343

WorkerHasAPublicModifier

When you define a ListenableWorker which is constructed using the
default WorkerFactory, the ListenableWorker sub-type needs to be public.

Vendor: Android Open Source Project
Identifier: androidx.work
Feedback: https://issuetracker.google.com/issues/new?component=409906

WrongRequiresOptIn

Experimental features defined in Kotlin source code must be annotated with the Kotlin
@RequiresOptIn annotation. Using androidx.annotation.RequiresOptIn will prevent the
Kotlin compiler from enforcing its opt-in policies.

Vendor: Android Open Source Project
Identifier: androidx.annotation.experimental
Feedback: https://issuetracker.google.com/issues/new?component=459778

Disabled Checks

One or more issues were not run by lint, either because the check is not enabled by default, or because it was disabled with a command line flag or via one or more lint.xml configuration files in the project directories.

AppCompatMethod

Disabled By: Default

When using the appcompat library, there are some methods you should be calling instead of the normal ones; for example, getSupportActionBar() instead of getActionBar(). This lint check looks for calls to the wrong method.

More info: https://developer.android.com/topic/libraries/support-library/

Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

AppLinksAutoVerify

Disabled By: Default

Ensures that app links are correctly set and associated with website.

More info: https://g.co/appindexing/applinks

BackButton

Disabled By: Default

According to the Android Design Guide,

"Other platforms use an explicit back button with label to allow the user to navigate up the application's hierarchy. Instead, Android uses the main action bar's app icon for hierarchical navigation and the navigation bar's back button for temporal navigation."

This check is not very sophisticated (it just looks for buttons with the label "Back"), so it is disabled by default to not trigger on common scenarios like pairs of Back/Next buttons to paginate through screens.

More info: https://d.android.com/r/studio-ui/designer/material/design

ComposableLambdaParameterNaming

Disabled By: Default

Composable functions with only one composable lambda parameter should use the name content for the parameter.

ComposableLambdaParameterPosition

Disabled By: Default

Composable functions with only one composable lambda parameter should place the parameter at the end of the parameter list, so it can be used as a trailing lambda.

ConvertToWebp

Disabled By: Default

The WebP format is typically more compact than PNG and JPEG. As of Android 4.2.1 it supports transparency and lossless conversion as well. Note that there is a quickfix in the IDE which lets you perform conversion.

Previously, launcher icons were required to be in the PNG format but that restriction is no longer there, so lint now flags these.
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

DalvikOverride

Disabled By: Default

The Dalvik virtual machine will treat a package private method in one class as overriding a package private method in its super class, even if they are in separate packages.

If you really did intend for this method to override the other, make the method protected instead.

If you did not intend the override, consider making the method private, or changing its name or signature.

Note that this check is disabled be default, because ART (the successor to Dalvik) no longer has this behavior.

DefaultEncoding

Disabled By: Default

Some APIs will implicitly use the default system character encoding instead of UTF-8 when converting to or from bytes, such as when creating a default FileReader.

This is usually not correct; you only want to do this if you need to read files created by other programs where they have deliberately written in the same encoding. The default encoding varies from platform to platform and can vary from locale to locale, so this makes it difficult to interpret files containing non-ASCII characters.

We recommend using UTF-8 everywhere.

Note that on Android, the default file encoding is always UTF-8 (see https://developer.android.com/reference/java/nio/charset/Charset#defaultCharset() for more), so this lint check deliberately does not flag any problems in Android code, since it is always safe to rely on the default character encoding there.

DuplicateStrings

Disabled By: Default

Duplicate strings can make applications larger unnecessarily.

This lint check looks for duplicate strings, including differences for strings where the only difference is in capitalization. Title casing and all uppercase can all be adjusted in the layout or in code.

More info: https://developer.android.com/reference/android/widget/TextView.html#attr_android:inputType

EasterEgg

Disabled By: Default

An "easter egg" is code deliberately hidden in the code, both from potential users and even from other developers. This lint check looks for code which looks like it may be hidden from sight.

ExpensiveAssertion

Disabled By: Default

In Kotlin, assertions are not handled the same way as from the Java programming language. In particular, they're just implemented as a library call, and inside the library call the error is only thrown if assertions are enabled.

This means that the arguments to the assert call will always be evaluated. If you're doing any computation in the expression being asserted, that computation will unconditionally be performed whether or not assertions are turned on. This typically turns into wasted work in release builds.

This check looks for cases where the assertion condition is nontrivial, e.g. it is performing method calls or doing more work than simple comparisons on local variables or fields.

You can work around this by writing your own inline assert method instead:

@Suppress("INVISIBLE_REFERENCE", "INVISIBLE_MEMBER")
inline fun assert(condition: () -> Boolean) {
    if (_Assertions.ENABLED && !condition()) {
        throw AssertionError()
    }
}

In Android, because assertions are not enforced at runtime, instead use this:

inline fun assert(condition: () -> Boolean) {
    if (BuildConfig.DEBUG && !condition()) {
        throw AssertionError()
    }
}

Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

GradleDependency

Disabled By: Command line flag

This detector looks for usages of libraries where the version you are using is not the current stable release. Using older versions is fine, and there are cases where you deliberately want to stick with an older version. However, you may simply not be aware that a more recent version is available, and that is what this lint check helps find.
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

IconDensities

Disabled By: Command line flag

Icons will look best if a custom version is provided for each of the major screen density classes (low, medium, high, extra high). This lint check identifies icons which do not have complete coverage across the densities.

Low density is not really used much anymore, so this check ignores the ldpi density. To force lint to include it, set the environment variable ANDROID_LINT_INCLUDE_LDPI=true. For more information on current density usage, see https://developer.android.com/about/dashboards

More info: https://developer.android.com/guide/practices/screens_support.html

IconExpectedSize

Disabled By: Default

There are predefined sizes (for each density) for launcher icons. You should follow these conventions to make sure your icons fit in with the overall look of the platform.

More info: https://d.android.com/r/studio-ui/designer/material/iconography

IconMissingDensityFolder

Disabled By: Command line flag

Icons will look best if a custom version is provided for each of the major screen density classes (low, medium, high, extra-high, extra-extra-high). This lint check identifies folders which are missing, such as drawable-hdpi.

Low density is not really used much anymore, so this check ignores the ldpi density. To force lint to include it, set the environment variable ANDROID_LINT_INCLUDE_LDPI=true. For more information on current density usage, see https://developer.android.com/about/dashboards

More info: https://developer.android.com/guide/practices/screens_support.html

InvalidPackage

Disabled By: Default

This check scans through libraries looking for calls to APIs that are not included in Android.

When you create Android projects, the classpath is set up such that you can only access classes in the API packages that are included in Android. However, if you add other projects to your libs/ folder, there is no guarantee that those .jar files were built with an Android specific classpath, and in particular, they could be accessing unsupported APIs such as java.applet.

This check scans through library jars and looks for references to API packages that are not included in Android and flags these. This is only an error if your code calls one of the library classes which wind up referencing the unsupported package.

InvalidPeriodicWorkRequestInterval

Disabled By: Command line flag

The interval duration for a PeriodicWorkRequest must be at least 15 minutes.

KotlinPropertyAccess

Disabled By: Default

For a method to be represented as a property in Kotlin, strict “bean”-style prefixing must be used.

Accessor methods require a get prefix or for boolean-returning methods an is prefix can be used.

More info: https://android.github.io/kotlin-guides/interop.html#property-prefixes

KotlincFE10

Disabled By: Default

K2, the new version of Kotlin compiler, which encompasses the new frontend, is coming. Try to avoid using internal APIs from the old frontend if possible.

LambdaLast

Disabled By: Default

To improve calling this code from Kotlin, parameter types eligible for SAM conversion should be last.

More info: https://android.github.io/kotlin-guides/interop.html#lambda-parameters-last

LintDocExample

Disabled By: Default

Lint's tool for generating documentation for each issue has special support for including a code example which shows how to trigger the report. It will pick the first unit test it can find and pick out the source file referenced from the error message, but you can instead designate a unit test to be the documentation example, and in that case, all the files are included.

To designate a unit test as the documentation example for an issue, name the test testDocumentationExample, or if your detector reports multiple issues, testDocumentationExample<Id>, such as testDocumentationExampleMyId.

LintImplPsiEquals

Disabled By: Default

You should never compare two PSI elements for equality with equals; use PsiEquivalenceUtil.areElementsEquivalent(PsiElement, PsiElement) instead.

LintImplUnexpectedDomain

Disabled By: Default

This checks flags URLs to domains that have not been explicitly allowed for use as a documentation source.

LogConditional

Disabled By: Default

The BuildConfig class provides a constant, DEBUG, which indicates whether the code is being built in release mode or in debug mode. In release mode, you typically want to strip out all the logging calls. Since the compiler will automatically remove all code which is inside a if (false) check, surrounding your logging calls with a check for BuildConfig.DEBUG is a good idea.

If you really intend for the logging to be present in release mode, you can suppress this warning with a @SuppressLint annotation for the intentional logging calls.

MangledCRLF

Disabled By: Default

On Windows, line endings are typically recorded as carriage return plus newline: \r\n.

This detector looks for invalid line endings with repeated carriage return characters (without newlines). Previous versions of the ADT plugin could accidentally introduce these into the file, and when editing the file, the editor could produce confusing visual artifacts.

More info: https://bugs.eclipse.org/bugs/show_bug.cgi?id=375421

MinSdkTooLow

Disabled By: Default

The value of the minSdkVersion property is too low and can be incremented without noticeably reducing the number of supported devices.
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

MissingDefaultResource

Disabled By: Command line flag

If a resource is only defined in folders with qualifiers like -land or -en, and there is no default declaration in the base folder (layout or values etc), then the app will crash if that resource is accessed on a device where the device is in a configuration missing the given qualifier.

As a special case, drawables do not have to be specified in the base folder; if there is a match in a density folder (such as drawable-mdpi) that image will be used and scaled. Note however that if you only specify a drawable in a folder like drawable-en-hdpi, the app will crash in non-English locales.

There may be scenarios where you have a resource, such as a -fr drawable, which is only referenced from some other resource with the same qualifiers (such as a -fr style), which itself has safe fallbacks. However, this still makes it possible for somebody to accidentally reference the drawable and crash, so it is safer to create a default fallback in the base folder. Alternatively, you can suppress the issue by adding tools:ignore="MissingDefaultResource" on the element.

(This scenario frequently happens with string translations, where you might delete code and the corresponding resources, but forget to delete a translation. There is a dedicated issue id for that scenario, with the id ExtraTranslation.)
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

MissingQuantity

Disabled By: Command line flag

Different languages have different rules for grammatical agreement with quantity. In English, for example, the quantity 1 is a special case. We write "1 book", but for any other quantity we'd write "n books". This distinction between singular and plural is very common, but other languages make finer distinctions.

This lint check looks at each translation of a <plural> and makes sure that all the quantity strings considered by the given language are provided by this translation.

For example, an English translation must provide a string for quantity="one". Similarly, a Czech translation must provide a string for quantity="few".

More info: https://developer.android.com/guide/topics/resources/string-resource.html#Plurals

MissingTranslation

Disabled By: Command line flag

If an application has more than one locale, then all the strings declared in one language should also be translated in all other languages.

If the string should not be translated, you can add the attribute translatable="false" on the <string> element, or you can define all your non-translatable strings in a resource file called donottranslate.xml. Or, you can ignore the issue with a tools:ignore="MissingTranslation" attribute.

You can tell lint (and other tools) which language is the default language in your res/values/ folder by specifying tools:locale="languageCode" for the root <resources> element in your resource file. (The tools prefix refers to the namespace declaration http://schemas.android.com/tools.)
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

NegativeMargin

Disabled By: Default

Margin values should be positive. Negative values are generally a sign that you are making assumptions about views surrounding the current one, or may be tempted to turn off child clipping to allow a view to escape its parent. Turning off child clipping to do this not only leads to poor graphical performance, it also results in wrong touch event handling since touch events are based strictly on a chain of parent-rect hit tests. Finally, making assumptions about the size of strings can lead to localization problems.

NewerVersionAvailable

Disabled By: Default

This detector checks with a central repository to see if there are newer versions available for the dependencies used by this project. This is similar to the GradleDependency check, which checks for newer versions available in the Android SDK tools and libraries, but this works with any MavenCentral dependency, and connects to the library every time, which makes it more flexible but also much slower.
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

NoHardKeywords

Disabled By: Default

Do not use Kotlin’s hard keywords as the name of methods or fields. These require the use of backticks to escape when calling from Kotlin. Soft keywords, modifier keywords, and special identifiers are allowed.

For example, ActionEvent's getWhen() method requires backticks when used from Kotlin:

val timestamp = event.`when`

More info: https://android.github.io/kotlin-guides/interop.html#no-hard-keywords

NoOp

Disabled By: Default

This check looks for code which looks like it's a no-op -- usually leftover expressions from interactive debugging, but in some cases bugs where you had intended to do something with the expression such as assign it to a field.

This check can be configured via the following options:

pure-getters (default is false):
Whether to assume methods with getter-names have no side effects.

Getter methods (where names start with get or is, and have non-void return types, and no arguments) should not have side effects. With this option turned on, lint will assume that is the case and will list any getter calls whose results are ignored as suspicious code.

To configure this option, use a `lint.xml` file in the project or source folder using an <option> block like the following:

 1 <lint>
 2     <issue id="NoOp">
 3         <option name="pure-getters" value="false" />                                                
 4     </issue>
 5 </lint>

PermissionNamingConvention

Disabled By: Default

Permissions should be prefixed with an app's package name, using reverse-domain-style naming. This prefix should be followed by .permission., and then a description of the capability that the permission represents, in upper SNAKE_CASE. For example, com.example.myapp.permission.ENGAGE_HYPERSPACE.

Following this recommendation avoids naming collisions, and helps clearly identify the owner and intention of a custom permission.

PrivacySandboxBlockedCall

Disabled By: Default

Many APIs are unavailable in the Privacy Sandbox, depending on the targetSdk.

If your code is designed to run in the sandbox (and never outside the sandbox) then you should remove the blocked calls to avoid exceptions at runtime.

If your code is part of a library that can be executed both inside and outside the sandbox, surround the code with if (!Process.isSdkSandbox()) { ... } (or use your own field or method annotated with @ChecksRestrictedEnvironment) to avoid executing blocked calls when in the sandbox. Or, add the @RestrictedForEnvironment annotation to the containing method if the entire method should not be called when in the sandbox.

This check is disabled by default, and should only be enabled in modules that may execute in the Privacy Sandbox.

Registered

Disabled By: Default

Activities, services and content providers should be registered in the AndroidManifest.xml file using <activity>, <service> and <provider> tags.

If your activity is simply a parent class intended to be subclassed by other "real" activities, make it an abstract class.

More info: https://developer.android.com/guide/topics/manifest/manifest-intro.html

RequiredSize

Disabled By: Default

All views must specify an explicit layout_width and layout_height attribute. There is a runtime check for this, so if you fail to specify a size, an exception is thrown at runtime.

It's possible to specify these widths via styles as well. GridLayout, as a special case, does not require you to specify a size.

SelectableText

Disabled By: Default

If a <TextView> is used to display data, the user might want to copy that data and paste it elsewhere. To allow this, the <TextView> should specify android:textIsSelectable="true".

This lint check looks for TextViews which are likely to be displaying data: views whose text is set dynamically.
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

StopShip

Disabled By: Default

Using the comment // STOPSHIP can be used to flag code that is incomplete but checked in. This comment marker can be used to indicate that the code should not be shipped until the issue is addressed, and lint will look for these. In Gradle projects, this is only checked for non-debug (release) builds.

In Kotlin, the TODO() method is also treated as a stop ship marker; you can use it to make incomplete code compile, but it will throw an exception at runtime and therefore should be fixed before shipping releases.
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

StringFormatInvalid

Disabled By: Command line flag

If a string contains a '%' character, then the string may be a formatting string which will be passed to String.format from Java code to replace each '%' occurrence with specific values.

This lint warning checks for two related problems:
(1) Formatting strings that are invalid, meaning that String.format will throw exceptions at runtime when attempting to use the format string.
(2) Strings containing '%' that are not formatting strings getting passed to a String.format call. In this case the '%' will need to be escaped as '%%'.

NOTE: Not all Strings which look like formatting strings are intended for use by String.format; for example, they may contain date formats intended for android.text.format.Time#format(). Lint cannot always figure out that a String is a date format, so you may get false warnings in those scenarios. See the suppress help topic for information on how to suppress errors in that case.

StringFormatTrivial

Disabled By: Default

Every call to String.format creates a new Formatter instance, which will decrease the performance of your app. String.format should only be used when necessary--if the formatted string contains only trivial conversions (e.g. b, s, c) and there are no translation concerns, it will be more efficient to replace them and concatenate with +.

SyntheticAccessor

Disabled By: Default

A private inner class which is accessed from the outer class will force the compiler to insert a synthetic accessor; this means that you are causing extra overhead. This is not important in small projects, but is important for large apps running up against the 64K method handle limit, and especially for libraries where you want to make sure your library is as small as possible for the cases where your library is used in an app running up against the 64K limit.
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

TypographyQuotes

Disabled By: Default

Straight single quotes and double quotes, when used as a pair, can be replaced by "curvy quotes" (or directional quotes). Use the right single quotation mark for apostrophes. Never use generic quotes ", ' or free-standing accents `, ´ for quotation marks, apostrophes, or primes. This can make the text more readable.

More info: https://en.wikipedia.org/wiki/Quotation_mark

Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

UnknownNullness

Disabled By: Default

To improve referencing this code from Kotlin, consider adding explicit nullness information here with either @NonNull or @Nullable.

This check can be configured via the following options:

ignore-deprecated (default is false):
Whether to ignore classes and members that have been annotated with @Deprecated.

Normally this lint check will flag all unannotated elements, but by setting this option to true it will skip any deprecated elements.

To configure this option, use a `lint.xml` file in the project or source folder using an <option> block like the following:

 1 <lint>
 2     <issue id="UnknownNullness">
 3         <option name="ignore-deprecated" value="false" />                                           
 4     </issue>
 5 </lint>

More info: https://developer.android.com/kotlin/interop#nullability_annotations

Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

UnsupportedChromeOsHardware

Disabled By: Default

The <uses-feature> element should not require this unsupported large screen hardware feature. Any <uses-feature> not explicitly marked with required="false" is necessary on the device to be installed on. Ensure that any features that might prevent it from being installed on a ChromeOS, large screen, or foldable device are reviewed and marked as not required in the manifest.

More info: https://developer.android.com/topic/arc/manifest.html#incompat-entries

Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

UnusedIds

Disabled By: Default

This resource id definition appears not to be needed since it is not referenced from anywhere. Having id definitions, even if unused, is not necessarily a bad idea since they make working on layouts and menus easier, so there is not a strong reason to delete these.

The unused resource check can ignore tests. If you want to include resources that are only referenced from tests, consider packaging them in a test source set instead.

You can include test sources in the unused resource check by setting the system property lint.unused-resources.include-tests =true, and to exclude them (usually for performance reasons), use lint.unused-resources.exclude-tests =true.

Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

ValidActionsXml

Disabled By: Default

Ensures that an actions XML file is properly formed
Note: This issue has an associated quickfix operation in Android Studio and IntelliJ IDEA.

VectorPath

Disabled By: Command line flag

Using long vector paths is bad for performance. There are several ways to make the pathData shorter:
* Using less precision
* Removing some minor details
* Using the Android Studio vector conversion tool
* Rasterizing the image (converting to PNG)

VulnerableCordovaVersion

Disabled By: Default

The version of Cordova used in the app is vulnerable to security issues. Please update to the latest Apache Cordova version.

More info: https://cordova.apache.org/announcements/2015/11/20/security.html

WrongThreadInterprocedural

Disabled By: Default

Searches for interprocedural call paths that violate thread annotations in the program. Tracks the flow of instantiated types and lambda expressions to increase accuracy across method boundaries.

More info: https://developer.android.com/guide/components/processes-and-threads.html#Threads

Suppressing Warnings and Errors

Lint errors can be suppressed in a variety of ways:

1. With a @SuppressLint annotation in the Java code
2. With a tools:ignore attribute in the XML file
3. With a //noinspection comment in the source code
4. With ignore flags specified in the build.gradle file, as explained below
5. With a lint.xml configuration file in the project
6. With a lint.xml configuration file passed to lint via the --config flag
7. With the --ignore flag passed to lint.

To suppress a lint warning with an annotation, add a @SuppressLint("id") annotation on the class, method or variable declaration closest to the warning instance you want to disable. The id can be one or more issue id's, such as "UnusedResources" or {"UnusedResources","UnusedIds"}, or it can be "all" to suppress all lint warnings in the given scope.

To suppress a lint warning with a comment, add a //noinspection id comment on the line before the statement with the error.

To suppress a lint warning in an XML file, add a tools:ignore="id" attribute on the element containing the error, or one of its surrounding elements. You also need to define the namespace for the tools prefix on the root element in your document, next to the xmlns:android declaration:
xmlns:tools="http://schemas.android.com/tools"

To suppress a lint warning in a build.gradle file, add a section like this:

android {
    lintOptions {
        disable 'TypographyFractions','TypographyQuotes'
    }
}

Here we specify a comma separated list of issue id's after the disable command. You can also use warning or error instead of disable to change the severity of issues.

To suppress lint warnings with a configuration XML file, create a file named lint.xml and place it at the root directory of the module in which it applies.

The format of the lint.xml file is something like the following:

<?xml version="1.0" encoding="UTF-8"?>
<lint>
    <!-- Ignore everything in the test source set -->
    <issue id="all">
        <ignore path="\*/test/\*" />
    </issue>

    <!-- Disable this given check in this project -->
    <issue id="IconMissingDensityFolder" severity="ignore" />

    <!-- Ignore the ObsoleteLayoutParam issue in the given files -->
    <issue id="ObsoleteLayoutParam">
        <ignore path="res/layout/activation.xml" />
        <ignore path="res/layout-xlarge/activation.xml" />
        <ignore regexp="(foo|bar)\.java" />
    </issue>

    <!-- Ignore the UselessLeaf issue in the given file -->
    <issue id="UselessLeaf">
        <ignore path="res/layout/main.xml" />
    </issue>

    <!-- Change the severity of hardcoded strings to "error" -->
    <issue id="HardcodedText" severity="error" />
</lint>

To suppress lint checks from the command line, pass the --ignore flag with a comma separated list of ids to be suppressed, such as:
$ lint --ignore UnusedResources,UselessLeaf /my/project/path

For more information, see https://developer.android.com/studio/write/lint.html#config