Bring activity in front on receiving Broadcast signal from another class

Question

I have main activity that just registers the broadcast receiver for ACTION_USER_RESENT. I have written the code for receiving the broadcast signal in another class as follows.

 public class ReceiverScreen extends BroadcastReceiver{
      @Override
      public void onReceive(Context context, Intent intent) {
           // TODO Auto-generated method stub
           if(intent.getAction().equals(Intent.ACTION_USER_PRESENT))
           {
                //?
           }
      }
 }

Scenario: When I run the program it runs and I am not exiting the program and just pressing the home button on device i.e. the app remains running.

Question: When I lock and unlock back the mobile it shows the home screen of the mobile. But I want my app to show after unlocking the mobile. What should I write inside the if condition above so that my app is visible first.

Please help...

Answer 1

You can write below code in your onReceive().

public void onReceive(Context context, Intent intent) {
        if(intent.getAction().equals(Intent.ACTION_USER_PRESENT))
        {

            Intent intent = new Intent(context,YourActivity.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(intent);
        }
    }

So, when screen is unlocked, your app will receive ACTION_USER_PRESENT broadcast and from there you can start your Application's Activity.

The Flag FLAG_ACTIVITY_NEW_TASK is required otherwise your app will crash with java.lang.RuntimeException because, Calling startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK flag.