What is the proper way to launch app using alarm manager? - flutter

Question

I need to implement a flutter alarm app that opens through the alarm manager.
It seems that there is the way to do it using android_intent and android_alarm_manager_plus.
I was looking for the right way to create such functionality, but this option does not work:
await AndroidAlarmManager.oneShot(
Duration(seconds: 2), 1, setAlarm);
void setAlarm()async{
AndroidIntent intent =
AndroidIntent(action: 'action_view', package: 'com.example.test_alarm');
await intent.launch().catchError((e) {
print(e.toString());
});
}
Debug console gives this:
I/IntentSender( 4886): Cannot resolve explicit intent - ignoring package
V/IntentSender( 4886): Sending intent Intent { act=android.intent.action.VIEW (has extras) }

Answer 1

try using https://pub.dev/packages/app_launcher
void setAlarm() async{
await AppLauncher.openApp(
androidApplicationId: "com.example.test_alarm",
);
}

Answer 2

I think your code is not working because the setAlarm() function will be run from Dart Background Isolate. So you need to modify the AlarmBroadcastReceiver.java code of plugin like below.
public class AlarmBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
PowerManager powerManager = (PowerManager)
context.getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wakeLock = powerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK |
PowerManager.ACQUIRE_CAUSES_WAKEUP |
PowerManager.ON_AFTER_RELEASE, "AlarmBroadcastReceiver:My wakelock");
Intent startIntent = context
.getPackageManager()
.getLaunchIntentForPackage(context.getPackageName());
if (startIntent != null)
startIntent.setFlags(
Intent.FLAG_ACTIVITY_REORDER_TO_FRONT |
Intent.FLAG_ACTIVITY_NEW_TASK |
Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
);
wakeLock.acquire(3 * 60 * 1000L /*3 minutes*/);
context.startActivity(startIntent);
AlarmService.enqueueAlarmProcessing(context, intent);
wakeLock.release();
}
}
If you want to launch your app on a lock screen, need to add codes at the MainActivity. Here is an example code.
class MainActivity : FlutterActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
// ...
turnScreenOnAndKeyguardOff()
}
private fun turnScreenOnAndKeyguardOff() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
setShowWhenLocked(true)
setTurnScreenOn(true)
window.addFlags(WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON)
} else {
window.addFlags(
WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED // deprecated api 27
or WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD // deprecated api 26
or WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON // deprecated api 27
or WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON
)
}
val keyguardMgr = getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
keyguardMgr.requestDismissKeyguard(this, null)
}
}
}