notif: Introduce AndroidIntent.flags; use existing flags from zulip-mobile

Author: rajveermalviya

android/app/src/main/kotlin/com/zulip/flutter/Notifications.g.kt

@@ -99,7 +99,9 @@ data class NotificationChannel (
 data class AndroidIntent (
   val action: String,
   val dataUrl: String,
-  val extras: Map<String?, String?>
+  val extras: Map<String?, String?>,
+  /** A combination of flags from [IntentFlag]. */
+  val flags: Long
 
 ) {
   companion object {
@@ -108,14 +110,16 @@ data class AndroidIntent (
       val action = __pigeon_list[0] as String
       val dataUrl = __pigeon_list[1] as String
       val extras = __pigeon_list[2] as Map<String?, String?>
-      return AndroidIntent(action, dataUrl, extras)
+      val flags = __pigeon_list[3].let { num -> if (num is Int) num.toLong() else num as Long }
+      return AndroidIntent(action, dataUrl, extras, flags)
     }
   }
   fun toList(): List<Any?> {
     return listOf(
       action,
       dataUrl,
       extras,
+      flags,
     )
   }
 }

android/app/src/main/kotlin/com/zulip/flutter/ZulipPlugin.kt

@@ -105,6 +105,7 @@ private class AndroidNotificationHost(val context: Context)
                         MainActivity::class.java
                     ).apply {
                         intent.extras.forEach { (k, v) -> putExtra(k!!, v!!) }
+                        flags = intent.flags.toInt()
                     } },
                     it.flags.toInt())
             ) }

lib/host/android_notifications.dart

@@ -68,3 +68,14 @@ abstract class IntentAction {
   /// Corresponds to `ACTION_VIEW`.
   static const view = 'android.intent.action.VIEW';
 }
+
+/// For use in [AndroidIntent.flags].
+///
+/// See: https://developer.android.com/reference/android/content/Intent#FLAG_ACTIVITY_BROUGHT_TO_FRONT
+abstract class IntentFlag {
+  /// Corresponds to `FLAG_ACTIVITY_CLEAR_TOP`.
+  static const activityClearTop = 1 << 26;
+
+  /// Corresponds to `FLAG_ACTIVITY_NEW_TASK`.
+  static const activityNewTask = 1 << 28;
+}

lib/host/android_notifications.g.dart

@@ -73,6 +73,7 @@ class AndroidIntent {
     required this.action,
     required this.dataUrl,
     required this.extras,
+    this.flags = 0,
   });
 
   String action;
@@ -81,11 +82,15 @@ class AndroidIntent {
 
   Map<String?, String?> extras;
 
+  /// A combination of flags from [IntentFlag].
+  int flags;
+
   Object encode() {
     return <Object?>[
       action,
       dataUrl,
       extras,
+      flags,
     ];
   }
 
@@ -95,6 +100,7 @@ class AndroidIntent {
       action: result[0]! as String,
       dataUrl: result[1]! as String,
       extras: (result[2] as Map<Object?, Object?>?)!.cast<String?, String?>(),
+      flags: result[3]! as int,
     );
   }
 }

lib/notifications/display.dart

@@ -196,10 +196,22 @@ class NotificationDisplayManager {
         intent: AndroidIntent(
           action: IntentAction.view,
           dataUrl: intentDataUrl.toString(),
-          extras: {}),
-        // TODO this doesn't set the Intent flags we set in zulip-mobile; is that OK?
-        //   (This is a legacy of `flutter_local_notifications`.)
-        ),
+          extras: {},
+          // See these sections in the Android docs:
+          //   https://developer.android.com/guide/components/activities/tasks-and-back-stack#TaskLaunchModes
+          //   https://developer.android.com/reference/android/content/Intent#FLAG_ACTIVITY_CLEAR_TOP
+          //
+          // * From the doc on `PendingIntent.getActivity` at
+          //     https://developer.android.com/reference/android/app/PendingIntent#getActivity(android.content.Context,%20int,%20android.content.Intent,%20int)
+          //   > Note that the activity will be started outside of the context of an
+          //   > existing activity, so you must use the Intent.FLAG_ACTIVITY_NEW_TASK
+          //   > launch flag in the Intent.
+          //
+          // * The flag FLAG_ACTIVITY_CLEAR_TOP is mentioned as being what the
+          //   notification manager does; so use that.  It has no effect as long
+          //   as we only have one activity; but if we add more, it will destroy
+          //   all the activities on top of the target one.
+          flags: IntentFlag.activityClearTop | IntentFlag.activityNewTask)),
       autoCancel: true,
     );
 

pigeon/notifications.dart

@@ -42,11 +42,14 @@ class NotificationChannel {
 ///   https://developer.android.com/reference/android/content/Intent
 ///   https://developer.android.com/reference/android/content/Intent#Intent(java.lang.String,%20android.net.Uri,%20android.content.Context,%20java.lang.Class%3C?%3E)
 class AndroidIntent {
-  AndroidIntent({required this.action, required this.dataUrl, required this.extras});
+  AndroidIntent({required this.action, required this.dataUrl, required this.extras, this.flags = 0});
 
   final String action;
   final String dataUrl;
   final Map<String?, String?> extras;
+
+  /// A combination of flags from [IntentFlag].
+  final int flags;
 }
 
 /// Corresponds to `android.app.PendingIntent`.

test/notifications/display_test.dart

@@ -225,7 +225,8 @@ void main() {
       final expectedGroupKey = '${data.realmUrl}|${data.userId}';
       final expectedId =
         NotificationDisplayManager.notificationIdAsHashOf(expectedTag);
-      const expectedIntentFlags = PendingIntentFlag.immutable;
+      const expectedPendingIntentFlags = PendingIntentFlag.immutable;
+      const expectedIntentFlags = IntentFlag.activityClearTop | IntentFlag.activityNewTask;
       final expectedSelfUserKey = '${data.realmUrl}|${data.userId}';
       final expectedIntentDataUrl = NotificationOpenPayload(
         realmUrl: data.realmUrl,
@@ -281,11 +282,12 @@ void main() {
             ..autoCancel.equals(true)
             ..contentIntent.which((it) => it.isNotNull()
               ..requestCode.equals(0)
-              ..flags.equals(expectedIntentFlags)
+              ..flags.equals(expectedPendingIntentFlags)
               ..intent.which((it) => it
                 ..action.equals(IntentAction.view)
                 ..dataUrl.equals(expectedIntentDataUrl.toString())
-                ..extras.deepEquals({}))),
+                ..extras.deepEquals({})
+                ..flags.equals(expectedIntentFlags))),
           (it) => it.isA<AndroidNotificationHostApiNotifyCall>()
             ..id.equals(NotificationDisplayManager.notificationIdAsHashOf(expectedGroupKey))
             ..tag.equals(expectedGroupKey)
@@ -1218,6 +1220,7 @@ extension on Subject<AndroidIntent> {
   Subject<String> get action => has((x) => x.action, 'action');
   Subject<String> get dataUrl => has((x) => x.dataUrl, 'dataUrl');
   Subject<Map<String?, String?>> get extras => has((x) => x.extras, 'extras');
+  Subject<int> get flags => has((x) => x.flags, 'flags');
 }
 
 extension on Subject<InboxStyle> {