Notification listener service not working after application crashed

If you already have permissions, follow these steps:

In your service class or other service / activity, you can switch the "hability of the component" to listen for notifications :

    public void tryReconnectService() {
        toggleNotificationListenerService();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            ComponentName componentName =
                    new ComponentName(getApplicationContext(), NotificationReaderV2Service.class);

            //It say to Notification Manager RE-BIND your service to listen notifications again inmediatelly!
            requestRebind(componentName);
        }
    }

/**
* Try deactivate/activate your component service
*/
    private void toggleNotificationListenerService() {
        PackageManager pm = getPackageManager();
        pm.setComponentEnabledSetting(new ComponentName(this, NotificationReaderV2Service.class),
                PackageManager.COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);
        pm.setComponentEnabledSetting(new ComponentName(this, NotificationReaderV2Service.class),
                PackageManager.COMPONENT_ENABLED_STATE_ENABLED, PackageManager.DONT_KILL_APP);
    }

      

        
        
        
      

    

Your notification listener is a SERVICE, it can be killed with System , you can make your service like FOREGROUND to drastically reduce the chances of the system killing your service.

@Override
    public void onListenerConnected() {
        super.onListenerConnected();
        Log.d(TAG, "Service Reader Connected");
    Notification not = createNotification();
    NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    if (mNotificationManager != null) {
        mNotificationManager.notify(NOTIFICATION_ID, not);
    }

    startForeground(NOTIFICATION_ID, not);

    //Alarm to auto - send Intents to Service to reconnect, you can ommit next line.
    alarmIt();
}

      

        
        
        
      

    

If you like "safe" more, you can program bad battery alarms, try using inaccurate alarms, please, the user's battery will be happy:

private void alarmIt() {
    Log.d(TAG, "ALARM PROGRAMMATED at"+HotUtils.formatDate(new Date()));
    Calendar now = Calendar.getInstance();
    now.setTimeInMillis(System.currentTimeMillis());
    now.set(Calendar.MINUTE, now.get(Calendar.MINUTE) + 1);

    Intent intent = new Intent(this, NotificationReaderV2Service.class);
    intent.addFlags(Intent.FLAG_RECEIVER_FOREGROUND);
    intent.setAction(REBIND_ACTION);

    PendingIntent pendingIntent = PendingIntent.getService(this, 0,
            intent, 0);

    AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);

    //The alarms that are repeated are inaccurate by default, use RTC_WAKE_UP at your convenience.
    //Alarm will fire every minute, CHANGE THIS iF DO YOU CAN, you can't use less than 1 minute to repeating alarms.
    manager.setRepeating(AlarmManager.RTC_WAKEUP, now.getTimeInMillis(), 1000 * 60 * 1, pendingIntent);
}

      

        
        
        
      

    

and then read the intent to re-attach the binding to the service:

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Log.d(TAG, "Notification service onStartCommandCalled");
    if (intent!=null && !HotUtils.isNullOrEmpty(intent.getAction()) && intent.getAction().equals(REBIND_ACTION)){
        Log.d(TAG, "TRYING REBIND SERVICE at "+HotUtils.formatDate(new Date()));
        tryReconnectService();//switch on/off component and rebind
    }
    //START_STICKY  to order the system to restart your service as soon as possible when it was killed.
    return START_STICKY;
}

      

        
        
        
      

    

Keep in mind that by following all these steps, you can be sure that your service will be killed anyway by the system, but this code will restart the service and make it difficult to kill it.

You might want to consider using PARTIAL_WAKE_LOCK with your service and execute it in process independently (: remote) if you want even more confidence (it might be useless)

I would like to add a frequently recurring error , NEVER override onBind and onUnbind method or overwrite INTENT ACTION. This will result in your service not being connected and never running onListenerConnected. Keep the intent as is, in most cases you don't need to edit it.