Alarmmanager not working when I closed the app from recent apps

Question

When my app is open or in running state alarm manager works fine but when I closed the app It does not working . I have also used Task removed method in service class still not getting alarm.

My code:-

ReminderActivity.java

public class ReminderActivity extends AppCompatActivity {
   static EditText mDatebtn, mTimebtn;
    @SuppressLint("StaticFieldLeak")
    static EditText mTitledit;
    private DBHandler dbHandler;
    TextView textView;
    private static final int REQ_CODE_SPEECH_INPUT = 100;
   private static TextToSpeech textToSpeech;
   static int layoutclick;
    //When user tap on the layout we will increment it , switch to case statement
    static String title,finaltime;
    static String finalalarm;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_reminder2);
        dbHandler = new DBHandler(this);
        mTitledit = (EditText) findViewById(R.id.editTitle);
        textView = findViewById(R.id.addreminder);
        mDatebtn = findViewById(R.id.btnDate);
        mTimebtn = findViewById(R.id.btnTime);
        textToSpeech = new TextToSpeech(this, new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int status) {
                if (status != TextToSpeech.ERROR) {
                    textToSpeech.setLanguage(Locale.US);
                    textToSpeech.setSpeechRate(1f);
                    textToSpeech.speak("Tell me the exact date", TextToSpeech.QUEUE_FLUSH, null);
                }
            }
        });
        textView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                    title = mTitledit.getText().toString();
                    processinsert(title, mDatebtn.getText().toString(), mTimebtn.getText().toString());
                }
                startActivity(new Intent(ReminderActivity.this,Home.class));

            }
        });
    }

     @RequiresApi(api = Build.VERSION_CODES.O)
     private void processinsert(String title, String date, String time) {

        String result = dbHandler.addreminder(title, date, time);//data inserting in sqlite                  //inserts the title,date,time into sql lite database
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

             setAlarm(title, date, time);                                                                //calls the set alarm method to set alarm
         }
        Toast.makeText(getApplicationContext(), result, Toast.LENGTH_SHORT).show();
    }


    private void setAlarm(String text, String date, String time) {
        AlarmManager am = (AlarmManager) getSystemService(Context.ALARM_SERVICE);                   //assigning alarm manager object to set alarm
        Intent intent = new Intent(getApplicationContext(), AlarmBroadcast.class);
        intent.putExtra("event", text);                                                       //sending data to alarm class to create channel and notification
        intent.putExtra("time", date);
        intent.putExtra("date", time);
         @SuppressLint("UnspecifiedImmutableFlag")
        PendingIntent pendingIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, intent, PendingIntent.FLAG_ONE_SHOT);
        finalalarm  = date + " " + mTimebtn.getText();
        Toast.makeText(getApplicationContext(), finalalarm, Toast.LENGTH_LONG).show();
        @SuppressLint("SimpleDateFormat")
        DateFormat formatter = new SimpleDateFormat("d-M-yyyy hh:mm");
        try {

            Date date1 = formatter.parse(finalalarm);
             //Toast.makeText(getApplicationContext(), dateandtime, Toast.LENGTH_LONG).show();
            am.set(AlarmManager.RTC_WAKEUP, date1.getTime(), pendingIntent);

            // Toast.makeText(getApplicationContext(), "Alarm set", Toast.LENGTH_SHORT).show();
        } catch (ParseException e) {
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_SHORT).show();
        }

    }

AlarmBroadcast.java

public class AlarmBroadcast extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Bundle bundle = intent.getExtras();
        String text = bundle.getString("event");
        String date = bundle.getString("date") + " " + bundle.getString("time");
        Intent mIntent = new Intent(context, NotificationMessage.class);
        mIntent.setAction(Intent.ACTION_MAIN);
        mIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        mIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(mIntent);

        Intent intentService = new Intent(context, AlarmService.class);
        intentService.putExtra("message",text);
        context.startService(intentService);

    }
}

AlarmService.java

public class AlarmService extends Service {
    private Vibrator vibrator;
    private MediaPlayer mediaPlayer;
    int count = 0;
    static String message;
    static TextToSpeech mTts;

    @RequiresApi(api = Build.VERSION_CODES.M)
    @Override
    public void onCreate() {
        super.onCreate();

        mediaPlayer = MediaPlayer.create(this, R.raw.reminder);

        vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);

    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        Intent intent1 = new Intent(this, NotificationMessage.class);
        message = intent.getStringExtra("message");

        PendingIntent pendingIntent = PendingIntent.getActivity(this, 1, intent1, PendingIntent.FLAG_ONE_SHOT);
        NotificationManager notificationManager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
         NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this, "notify_001");
        //here we set all the properties for the notification
        RemoteViews contentView = new RemoteViews(this.getPackageName(), R.layout.notification_layout);
        contentView.setImageViewResource(R.id.image, R.mipmap.ic_launcher);
        PendingIntent pendingSwitchIntent = PendingIntent.getBroadcast(this, 0, intent, 0);
        contentView.setOnClickPendingIntent(R.id.flashButton, pendingSwitchIntent);
        contentView.setTextViewText(R.id.message, intent.getStringExtra("message"));
        contentView.setTextViewText(R.id.date, "date");
        mBuilder.setSmallIcon(R.drawable.alarm);
        mBuilder.setOngoing(true);
        mBuilder.setAutoCancel(true);
        mBuilder.setPriority(Notification.PRIORITY_HIGH);
        mBuilder.setOnlyAlertOnce(true);
        mBuilder.build().flags = Notification.FLAG_NO_CLEAR | Notification.PRIORITY_HIGH;
        intent1.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP
                | Intent.FLAG_ACTIVITY_SINGLE_TOP);
        mBuilder.setContent(contentView);
        mBuilder.setContentIntent(pendingIntent);

        //we have to create notification channel after api level 26
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            String channelId = "channel_id";
            NotificationChannel channel = new NotificationChannel(channelId, "channel name", NotificationManager.IMPORTANCE_HIGH);
            channel.enableVibration(true);
            notificationManager.createNotificationChannel(channel);
            mBuilder.setChannelId(channelId);
            mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                @Override
                public void onCompletion(MediaPlayer mp) {
                    if (count < 2) {
                        mp.start();
                        count++;
                    }
                }
            });
            mediaPlayer.start();

            Notification notification = mBuilder.build();
            notificationManager.cancelAll();
            long[] pattern = {0, 100, 1000, 200, 2000};
            vibrator.vibrate(pattern, -1);
            startForeground(1, notification);
        }
        return START_STICKY;
    }


    @Override
    public void onDestroy() {
        super.onDestroy();
        mediaPlayer.stop();
        vibrator.cancel();

    }


    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
 
        return null;
    }


    @Override
    public void onTaskRemoved(Intent rootIntent) {
        super.onTaskRemoved(rootIntent);

        @SuppressLint("UnspecifiedImmutableFlag") PendingIntent service = PendingIntent.getService(
                getApplicationContext(),
                1001,
                new Intent(getApplicationContext(), AlarmService.class),
                PendingIntent.FLAG_ONE_SHOT);

        AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        alarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP, 1000, service);
    }
    }
}

NotificationMessage.java

public class AlarmBroadcast extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Bundle bundle = intent.getExtras();
        String text = bundle.getString("event");
        String date = bundle.getString("date") + " " + bundle.getString("time");
        Intent mIntent = new Intent(context, NotificationMessage.class);
        mIntent.setAction(Intent.ACTION_MAIN);
        mIntent.addCategory(Intent.CATEGORY_LAUNCHER);
        mIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(mIntent);

        Intent intentService = new Intent(context, AlarmService.class);
        intentService.putExtra("message",text);
        context.startService(intentService);

    }
}

Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.tensorflow.lite.examples.detection">

    <uses-sdk />
     <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />
    <uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" />
    <uses-permission android:name="com.android.alarm.permission.SET_ALARM" />
    <uses-feature android:name="android.hardware.camera" />
    <uses-feature android:name="android.hardware.camera.autofocus" />
    <uses-permission android:name="android.permission.VIBRATE" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/blind"
        android:label="@string/app_name"
        android:roundIcon="@drawable/blind"
        android:supportsRtl="true"
        android:theme="@style/AppTheme.ObjectDetection">

        <activity
            android:name=".Reminder.NotificationMessage"
            android:exported="true"
            >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
        </activity>
        <activity
            android:name=".Reminder.ReminderActivity"
            android:exported="true" />
        <activity
            android:name=".Reminder.Reminder"
            android:exported="true" />     
        <activity
            android:name=".Home"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
         <receiver android:name=".Reminder.AlarmBroadcast"
             android:enabled="true"
            android:exported="true">
         </receiver>
        <service android:name=".Reminder.AlarmService" />
    </application>

</manifest>

The alarm seems to work flawlessly when the app is open, or running in the background, but as soon as I exit the app, it seems to completely stop. Can I also add multiple alarms?

Answer 1

This behavior is by design -- if a user force-closes the app (which is the same thing as removing it from recent apps), the app will not be allowed to do anything at all -- no alarms, no responding to intent broadcasts, no background services, etc.

I think that the only thing it'll be allowed to do is receive FCM notifications, but even with that one, I'm not 100% sure.

The bottom line is that if the user purposefully shuts down your app, Google wants it to stay shut down, until the user opens it again