How to start an activity from BroadcastReceiver's onReceive() method when app is in background?

Question

I want to start an activity from the onReceive() method of the BroadcastReceiver. This is the code i am using:

class TimeReminderReceiver : BroadcastReceiver() {
     override fun onReceive(p0: Context?, p1: Intent?) {
         println("RECEIVED")

         val i = Intent(p0!!, TimeReminderActivity::class.java)
         i.flags = Intent.FLAG_ACTIVITY_NEW_TASK
         p0.startActivity(i)
     }
}

There are many answers for this question in stackoverflow, i tried all of it and none of it is working for me. The app just prints RECEIVED and stays there. Nothing shows at the logcat, no exception, nothing. I have added the receiver in the mainfest also.

<receiver
        android:name=".receivers_and_activities.TimeReminderReceiver" />

Whats the problem with this code?

EDIT:

Code that calls the broadcast:

val intent = Intent(this@MainActivity, TimeReminderReceiver::class.java)
val pendingIntent = PendingIntent.getBroadcast(this@MainActivity, 0, intent,
                    PendingIntent.FLAG_UPDATE_CURRENT)
val am = this@MainActivity.getSystemService(Context.ALARM_SERVICE) as AlarmManager
am.set(AlarmManager.RTC_WAKEUP, calendar.timeInMillis, pendingIntent)

Is your App is in Foreground? or Background? and on which API level you're testing it? — Muhammad Farhan, Feb 12 '20 at 06:37
when I receive the broadcast, my app is in background. I am testing on API level 29. My project's sdk version is also 29. — eegooDeveloper, Feb 12 '20 at 06:41
@MuhammadFarhan i just found out that when the app is in foreground while receiving the broadcast, activity opens fine. — eegooDeveloper, Feb 12 '20 at 06:46
@eegooDeveloper calling this broadcast form where can u show code? — iamkdblue, Feb 12 '20 at 06:46
@kdblue i got that code from [Schedule repeating alarms](https://developer.android.com/training/scheduling/alarms) — eegooDeveloper, Feb 12 '20 at 06:54

score 9 · Accepted Answer · answered Feb 12 '20 at 08:02

As you commented out you are trying to launch an Activity when your App is in Background on Android 10 (API level 29).

From Android (API level 29) they put some restrictions to open an Activity when your App is in Background.

Android 10 (API level 29) and higher place restrictions on when apps can start activities when the app is running in the background.

You can find out here Restrictions on starting activities from the background.

They have also mentioned that

In nearly all cases, apps that are in the background should display time-sensitive notifications to provide urgent information to the user instead of directly starting an activity. Examples of when to use such notifications include handling an incoming phone call or an active alarm clock.

So to overcome this behavior instead of calling your App when it is in the background you should show high-priority notification with a full-screen intent.

For more information on High-Priority Notification and Full-Screen Intent, you can check it here Display time-sensitive notifications

How to start an activity from BroadcastReceiver's onReceive() method when app is in background?

1 Answers1