PendingIntent.getActivity with FLAG_UPDATE_CURRENT won't update intent's flags

Question

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        Toast.makeText(this, "onNewIntent", Toast.LENGTH_SHORT).show();
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Intent a = new Intent(this, MainActivity.class);
        Intent b = new Intent(this, MainActivity.class);
        b.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
        PendingIntent pia = PendingIntent.getActivity(this, 1, a, 0);
        PendingIntent pib = PendingIntent.getActivity(this, 1, b, PendingIntent.FLAG_UPDATE_CURRENT);
        try {
            pib.send();
        } catch (PendingIntent.CanceledException e) {
            e.printStackTrace();
        }
    }

}

With above code, when Activity starts, instead of an "onNewIntent" toast pops up, a new MainActivity invoked, ignores FLAG_ACTIVITY_SINGLE_TOP flag.

But if I change FLAG_UPDATE_CURRENT to FLAG_CANCEL_CURRENT, problem solved.

Is this a bug of Android? I'm testing this on an emulator running Android Pie.

Is there any way to update PendingIntent's flag?

Answer 1

When you use PendingIntent.FLAG_UPDATE_CURRENT this only causes the "extras" in the Intent to be updated. It does nothing to the Intent flags.

If you want to change the Intent flags, you need to either use 2 different PendingIntents (by using different requestCodes, for example), or you need to cancel the existing PendingIntent and create a new one.