[various] report when a notification is dismissed by the user

Resolves #74. Adds an opt-in `emitDismissEvent` flag to
`AndroidNotificationDetails` and maps iOS/macOS dismissals (for categories
configured with `customDismissAction`) to a new
`NotificationResponseType.notificationDismissed`. The dismissal is delivered
through the existing notification response callbacks, reusing the background
isolate pipeline already used for notification actions.

Author: vlaushkin

flutter_local_notifications/android/src/main/java/com/dexterous/flutterlocalnotifications/ActionBroadcastReceiver.java

@@ -28,6 +28,8 @@
 public class ActionBroadcastReceiver extends BroadcastReceiver {
   public static final String ACTION_TAPPED =
       "com.dexterous.flutterlocalnotifications.ActionBroadcastReceiver.ACTION_TAPPED";
+  public static final String ACTION_DISMISSED =
+      "com.dexterous.flutterlocalnotifications.ActionBroadcastReceiver.ACTION_DISMISSED";
   private static final String TAG = "ActionBroadcastReceiver";
   @Nullable private static ActionEventSink actionEventSink;
   @Nullable private static FlutterEngine engine;
@@ -43,7 +45,8 @@ public ActionBroadcastReceiver() {}
 
   @Override
   public void onReceive(Context context, Intent intent) {
-    if (!ACTION_TAPPED.equalsIgnoreCase(intent.getAction())) {
+    if (!ACTION_TAPPED.equalsIgnoreCase(intent.getAction())
+        && !ACTION_DISMISSED.equalsIgnoreCase(intent.getAction())) {
       return;
     }
 

flutter_local_notifications/android/src/main/java/com/dexterous/flutterlocalnotifications/FlutterLocalNotificationsPlugin.java

@@ -298,6 +298,22 @@ protected static Notification createNotification(
             .setSilent(BooleanUtils.getValue(notificationDetails.silent))
             .setOnlyAlertOnce(BooleanUtils.getValue(notificationDetails.onlyAlertOnce));
 
+    if (BooleanUtils.getValue(notificationDetails.emitDismissEvent)) {
+      Intent deleteIntent = new Intent(context, ActionBroadcastReceiver.class);
+      deleteIntent.setAction(ActionBroadcastReceiver.ACTION_DISMISSED);
+      deleteIntent
+          .putExtra(NOTIFICATION_ID, notificationDetails.id)
+          .putExtra(NOTIFICATION_TAG, notificationDetails.tag)
+          .putExtra(PAYLOAD, notificationDetails.payload);
+      int deleteFlags = PendingIntent.FLAG_UPDATE_CURRENT;
+      if (VERSION.SDK_INT >= VERSION_CODES.M) {
+        deleteFlags |= PendingIntent.FLAG_IMMUTABLE;
+      }
+      PendingIntent deletePendingIntent =
+          PendingIntent.getBroadcast(context, notificationDetails.id, deleteIntent, deleteFlags);
+      builder.setDeleteIntent(deletePendingIntent);
+    }
+
     if (notificationDetails.actions != null) {
       // Space out request codes by 16 so even with 16 actions they won't clash
       int requestCode = notificationDetails.id * 16;
@@ -660,6 +676,10 @@ static Map<String, Object> extractNotificationResponseMap(Intent intent) {
       notificationResponseMap.put(NOTIFICATION_RESPONSE_TYPE, 1);
     }
 
+    if (ActionBroadcastReceiver.ACTION_DISMISSED.equals(intent.getAction())) {
+      notificationResponseMap.put(NOTIFICATION_RESPONSE_TYPE, 2);
+    }
+
     return notificationResponseMap;
   }
 

flutter_local_notifications/android/src/main/java/com/dexterous/flutterlocalnotifications/models/NotificationDetails.java

@@ -122,6 +122,7 @@ public class NotificationDetails implements Serializable {
   private static final String MATCH_DATE_TIME_COMPONENTS = "matchDateTimeComponents";
 
   private static final String FULL_SCREEN_INTENT = "fullScreenIntent";
+  private static final String EMIT_DISMISS_EVENT = "emitDismissEvent";
   private static final String SHORTCUT_ID = "shortcutId";
   private static final String SUB_TEXT = "subText";
   private static final String ACTIONS = "actions";
@@ -191,6 +192,7 @@ public class NotificationDetails implements Serializable {
   public DateTimeComponents matchDateTimeComponents;
   public Long when;
   public Boolean fullScreenIntent;
+  public Boolean emitDismissEvent;
   public String shortcutId;
   public String subText;
   public @Nullable List<NotificationAction> actions;
@@ -290,6 +292,8 @@ private static void readPlatformSpecifics(
       notificationDetails.category = (String) platformChannelSpecifics.get(CATEGORY);
       notificationDetails.fullScreenIntent =
           (Boolean) platformChannelSpecifics.get((FULL_SCREEN_INTENT));
+      notificationDetails.emitDismissEvent =
+          (Boolean) platformChannelSpecifics.get(EMIT_DISMISS_EVENT);
       notificationDetails.shortcutId = (String) platformChannelSpecifics.get(SHORTCUT_ID);
       notificationDetails.additionalFlags = (int[]) platformChannelSpecifics.get(ADDITIONAL_FLAGS);
       notificationDetails.subText = (String) platformChannelSpecifics.get(SUB_TEXT);

flutter_local_notifications/example/lib/main.dart

@@ -62,8 +62,20 @@ const String darwinNotificationCategoryText = 'textCategory';
 /// Defines a iOS/MacOS notification category for plain actions.
 const String darwinNotificationCategoryPlain = 'plainCategory';
 
+/// Defines a iOS/MacOS notification category that reports dismissals.
+const String dismissableNotificationCategory = 'dismissableCategory';
+
 @pragma('vm:entry-point')
 void notificationTapBackground(NotificationResponse notificationResponse) {
+  if (notificationResponse.notificationResponseType ==
+      NotificationResponseType.notificationDismissed) {
+    // ignore: avoid_print
+    print(
+      'notification(${notificationResponse.id}) dismissed with'
+      ' payload: ${notificationResponse.payload}',
+    );
+    return;
+  }
   // ignore: avoid_print
   print(
     'notification(${notificationResponse.id}) action tapped: '
@@ -135,6 +147,14 @@ Future<void> main() async {
             DarwinNotificationCategoryOption.hiddenPreviewShowTitle,
           },
         ),
+        const DarwinNotificationCategory(
+          dismissableNotificationCategory,
+          // The customDismissAction option is required for iOS/macOS to report
+          // when the user dismisses a notification belonging to this category.
+          options: <DarwinNotificationCategoryOption>{
+            DarwinNotificationCategoryOption.customDismissAction,
+          },
+        ),
       ];
 
   /// Note: permissions aren't requested here just to demonstrate that can be
@@ -372,6 +392,15 @@ class _HomePageState extends State<HomePage> {
     selectNotificationStream.stream.listen((
       NotificationResponse? response,
     ) async {
+      if (response?.notificationResponseType ==
+          NotificationResponseType.notificationDismissed) {
+        // ignore: avoid_print
+        print(
+          'notification(${response?.id}) dismissed with'
+          ' payload: ${response?.payload}',
+        );
+        return;
+      }
       await Navigator.of(context).push(
         MaterialPageRoute<void>(
           builder: (BuildContext context) => SecondPage(
@@ -447,6 +476,13 @@ class _HomePageState extends State<HomePage> {
                   await _showNotification();
                 },
               ),
+              PaddedElevatedButton(
+                buttonText:
+                    'Show notification that reports when it is dismissed',
+                onPressed: () async {
+                  await _showDismissibleNotification();
+                },
+              ),
               PaddedElevatedButton(
                 buttonText:
                     'Show plain notification that has no title with '
@@ -1146,6 +1182,35 @@ class _HomePageState extends State<HomePage> {
     );
   }
 
+  Future<void> _showDismissibleNotification() async {
+    const AndroidNotificationDetails androidNotificationDetails =
+        AndroidNotificationDetails(
+          'your channel id',
+          'your channel name',
+          channelDescription: 'your channel description',
+          importance: Importance.max,
+          priority: Priority.high,
+          ticker: 'ticker',
+          emitDismissEvent: true,
+        );
+    const DarwinNotificationDetails darwinNotificationDetails =
+        DarwinNotificationDetails(
+          categoryIdentifier: dismissableNotificationCategory,
+        );
+    const NotificationDetails notificationDetails = NotificationDetails(
+      android: androidNotificationDetails,
+      iOS: darwinNotificationDetails,
+      macOS: darwinNotificationDetails,
+    );
+    await flutterLocalNotificationsPlugin.show(
+      id: id++,
+      title: 'dismiss me',
+      body: 'swipe me away to trigger a dismiss event',
+      notificationDetails: notificationDetails,
+      payload: 'dismissible item',
+    );
+  }
+
   Future<void> _showNotificationWithActions() async {
     const AndroidNotificationDetails
     androidNotificationDetails = AndroidNotificationDetails(

flutter_local_notifications/ios/flutter_local_notifications/Sources/flutter_local_notifications/FlutterLocalNotificationsPlugin.m

@@ -1029,9 +1029,11 @@ - (NSMutableDictionary *)extractNotificationResponseDict:
           isEqualToString:UNNotificationDefaultActionIdentifier]) {
     notitificationResponseDict[NOTIFICATION_RESPONSE_TYPE] =
         [NSNumber numberWithInteger:0];
-  } else if (response.actionIdentifier != nil &&
-             ![response.actionIdentifier
+  } else if ([response.actionIdentifier
                  isEqualToString:UNNotificationDismissActionIdentifier]) {
+    notitificationResponseDict[NOTIFICATION_RESPONSE_TYPE] =
+        [NSNumber numberWithInteger:2];
+  } else if (response.actionIdentifier != nil) {
     notitificationResponseDict[ACTION_ID] = response.actionIdentifier;
     notitificationResponseDict[NOTIFICATION_RESPONSE_TYPE] =
         [NSNumber numberWithInteger:1];

flutter_local_notifications/lib/src/callback_dispatcher.dart

@@ -41,14 +41,20 @@ void callbackDispatcher() {
           } else {
             id = -1;
           }
+          // A plain action tap doesn't include a response type, so default to
+          // it when none is provided.
+          final Object? responseTypeIndex = event['notificationResponseType'];
+          final NotificationResponseType notificationResponseType =
+              responseTypeIndex is int
+              ? NotificationResponseType.values[responseTypeIndex]
+              : NotificationResponseType.selectedNotificationAction;
           callback?.call(
             NotificationResponse(
               id: id,
               actionId: event['actionId'],
               input: event['input'],
               payload: event['payload'],
-              notificationResponseType:
-                  NotificationResponseType.selectedNotificationAction,
+              notificationResponseType: notificationResponseType,
             ),
           );
         });

flutter_local_notifications/lib/src/platform_specifics/android/method_channel_mappers.dart

@@ -233,6 +233,7 @@ extension AndroidNotificationDetailsMapper on AndroidNotificationDetails {
           'colorized': colorized,
           'number': number,
           'audioAttributesUsage': audioAttributesUsage.value,
+          'emitDismissEvent': emitDismissEvent,
         }
         ..addAll(_convertActionsToMap(actions))
         ..addAll(_convertStyleInformationToMap())

flutter_local_notifications/lib/src/platform_specifics/android/notification_details.dart

@@ -156,6 +156,7 @@ class AndroidNotificationDetails {
     this.colorized = false,
     this.number,
     this.audioAttributesUsage = AudioAttributesUsage.notification,
+    this.emitDismissEvent = false,
   });
 
   /// The icon that should be used when displaying the notification.
@@ -426,4 +427,13 @@ class AndroidNotificationDetails {
   /// such as alarm or ringtone set in [`AudioAttributes.Builder`](https://developer.android.com/reference/android/media/AudioAttributes.Builder#setUsage(int)).
   /// https://developer.android.com/reference/android/media/AudioAttributes
   final AudioAttributesUsage audioAttributesUsage;
+
+  /// Whether to report when the notification is dismissed by the user.
+  ///
+  /// When set to `true`, swiping the notification away or clearing it triggers
+  /// the `onDidReceiveBackgroundNotificationResponse` callback with a
+  /// [NotificationResponse] of type
+  /// [NotificationResponseType.notificationDismissed]. Dismissals caused by
+  /// tapping the notification or by calling `cancel` are not reported.
+  final bool emitDismissEvent;
 }

flutter_local_notifications/macos/flutter_local_notifications/Sources/flutter_local_notifications/FlutterLocalNotificationsPlugin.swift

@@ -149,8 +149,6 @@ public class FlutterLocalNotificationsPlugin: NSObject, FlutterPlugin, UNUserNot
                 launchingAppFromNotification = true
             }
 
-            completionHandler()
-        } else if response.actionIdentifier == UNNotificationDismissActionIdentifier {
             completionHandler()
         } else {
             if initialized {
@@ -612,7 +610,9 @@ public class FlutterLocalNotificationsPlugin: NSObject, FlutterPlugin, UNUserNot
         notificationResponseDict["notificationId"] = Int(response.notification.request.identifier)!
         if response.actionIdentifier == UNNotificationDefaultActionIdentifier {
             notificationResponseDict[MethodCallArguments.notificationResponseType] = 0
-        } else if response.actionIdentifier != UNNotificationDismissActionIdentifier {
+        } else if response.actionIdentifier == UNNotificationDismissActionIdentifier {
+            notificationResponseDict[MethodCallArguments.notificationResponseType] = 2
+        } else {
             notificationResponseDict[MethodCallArguments.actionId] = response.actionIdentifier
             notificationResponseDict[MethodCallArguments.notificationResponseType] = 1
         }