Can't start activity from BroadcastReceiver on android 10

Question

I updated my OS version to android 10 last night, and since then the startActivity function inside the broadcast receiver is doing nothing. This is how I try to start the activity based on the answer of CommonsWare:

Intent i = new Intent(context, AlarmNotificationActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) { // This is at least android 10...

                Log.d("Debug", "This is android 10");
                // Start the alert via full-screen intent.
                PendingIntent startAlarmPendingIntent = PendingIntent.getBroadcast(context, 0, i, PendingIntent.FLAG_UPDATE_CURRENT);
                String CHANNEL_ID = "my_channel_02";
                NotificationChannel channel = new NotificationChannel(CHANNEL_ID,
                        context.getString(R.string.notification_channel_name_second),
                        NotificationManager.IMPORTANCE_HIGH);
                NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
                notificationManager.createNotificationChannel(channel);
                NotificationCompat.Builder builder = new NotificationCompat.Builder(context, CHANNEL_ID)
                        .setContentTitle("Um, hi!")
                        .setAutoCancel(true)
                        .setPriority(NotificationCompat.PRIORITY_HIGH)
                        .setFullScreenIntent(startAlarmPendingIntent, true);
                Log.d("Debug", "Try to load screen");
                notificationManager.notify(0, builder.build());

            }

The log shows that I am getting to the notify command but nothing happens. I am asking for USE_FULL_SCREEN_INTENT permission on the manifest so I should be able to use full-screen intents. My app is useless now because of that issue. Does anyone know how to solve it?

Answer 1

Android 10's restriction on background activity starts was announced about six months ago. You can read more about it in the documentation.

Use a high-priority notification, with an associated full-screen Intent, instead. See the documentation. This sample app demonstrates this, by using WorkManager to trigger a background event needing to alert the user. There, I use a high-priority notification instead of starting the activity directly:

val pi = PendingIntent.getActivity(
  appContext,
  0,
  Intent(appContext, MainActivity::class.java),
  PendingIntent.FLAG_UPDATE_CURRENT
)

val builder = NotificationCompat.Builder(appContext, CHANNEL_WHATEVER)
  .setSmallIcon(R.drawable.ic_notification)
  .setContentTitle("Um, hi!")
  .setAutoCancel(true)
  .setPriority(NotificationCompat.PRIORITY_HIGH)
  .setFullScreenIntent(pi, true)

val mgr = appContext.getSystemService(NotificationManager::class.java)

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O
  && mgr.getNotificationChannel(CHANNEL_WHATEVER) == null
) {
  mgr.createNotificationChannel(
    NotificationChannel(
      CHANNEL_WHATEVER,
      "Whatever",
      NotificationManager.IMPORTANCE_HIGH
    )
  )
}

mgr.notify(NOTIF_ID, builder.build())