How to cold start a React Native app over device lock screen?

Question

I'm building a VoIP app on React Native, which detects incoming calls using push notifications. I need to start the app and bring it to the foreground on receiving a push notification. I'm able to achieve that for the following scenarios:

1. When the device is unlocked and:
   • The app is minimized (is still in the background)
   • The app is not in the background (killed from multitasking view)
2. When the device is locked and:
   • The app is minimized (is still in the background)

The only scenario I'm not able to handle is when the device is locked and the app is killed. The app starts but does not show up over the lock screen. Instead, the user needs to unlock the phone to access the app.

Here's the piece of code that runs when a notification is received,

@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    Intent notificationIntent = new Intent(this, MainActivity.class);
    // Check if app is running

    if(MainActivity.isAppRunning) {
        startActivity(notificationIntent);
        Intent messagingEvent = new Intent(MESSAGE_EVENT);
        messagingEvent.putExtra("message", remoteMessage);
        // Broadcast it so it is only available to the RN Application
        LocalBroadcastManager
                .getInstance(this)
                .sendBroadcast(messagingEvent);
    } else {
        startActivity(notificationIntent);
        try {
            // If the app is in the background we send it to the Headless JS Service
            Intent headlessIntent = new Intent(
                    this.getApplicationContext(),
                    BackgroundListenService.class
            );
            headlessIntent.putExtra("message", remoteMessage);
            this
                    .getApplicationContext()
                    .startService(headlessIntent);
            Log.d(TAG, "message: " + remoteMessage);
            HeadlessJsTaskService.acquireWakeLockNow(this.getApplicationContext());
        } catch (IllegalStateException ex) {
            Log.e(
                    TAG,
                    "Background messages will only work if the message priority is set to 'high'",
                    ex
            );
        }
    }
}

And here's my MainActivity:

public class MainActivity extends NavigationActivity {

  public static boolean isAppRunning;
  private static boolean isMessageRecieved;

    private class MessageReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            isMessageRecieved=true;
            Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
            window.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
            window.addFlags(WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
            window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
            window.clearFlags(WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY);
        }
    }

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    SplashScreen.show(this);
    super.onCreate(savedInstanceState);
    isAppRunning = true;

      LocalBroadcastManager localBroadcastManager = LocalBroadcastManager.getInstance(this);
      // Subscribe to message events
      localBroadcastManager.registerReceiver(
          new MainActivity.MessageReceiver(),
          new IntentFilter(MyFirebaseMessagingService.MESSAGE_EVENT)
      );

      if(isMessageRecieved) {
          Window window = getWindow();
          window.clearFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD);
          window.clearFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
          window.clearFlags(WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
          window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
          window.clearFlags(WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY);
      }

    NotificationManager notificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

    String channelId = "1";
    String channel2 = "2";

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
      NotificationChannel notificationChannel = new NotificationChannel(channelId,
              "Channel 1",NotificationManager.IMPORTANCE_HIGH);

      notificationChannel.setDescription("This is BNT");
      notificationChannel.setLightColor(Color.RED);
      notificationChannel.enableVibration(true);
      notificationChannel.setShowBadge(true);
      notificationManager.createNotificationChannel(notificationChannel);

      NotificationChannel notificationChannel2 = new NotificationChannel(channel2,
              "Channel 2",NotificationManager.IMPORTANCE_MIN);

      notificationChannel.setDescription("This is bTV");
      notificationChannel.setLightColor(Color.RED);
      notificationChannel.enableVibration(true);
      notificationChannel.setShowBadge(true);
      notificationManager.createNotificationChannel(notificationChannel2);

    } 
  }
   @Override
    protected void onDestroy() {
        super.onDestroy();
        isAppRunning = false;
    }

    @Override
    public void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        setIntent(intent);
    }

}