如何正确停止Android Alarmmanager

Question

I have an alarm manager that triggers at regular interval. A button in activity_main triggers it.

It works fine. Without any problem. Alarm manager is defined in Main class. A method (activated on button click) invokes the alarm manager. Another method should stop it or cancel it.

Code:

     public class MainActivity extends Activity {
    private PendingIntent pi;
       private AlarmManager alarmManager;

    .......................................
    ......................

    public void activate(View view) {
    //this activates the alarm manager.

    alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
    alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, pi.getBroadcast(this, 1, i, pi.FLAG_UPDATE_CURRENT));
    }

    public void deactivate(View view) {
//this should Deactivate the alarm manager.

    alarmManager.cancel(pi);

    }

    }

However, the second method is not working. (deactivate).

When the 2nd button is clicked, the App will crash!!

Log cat gives the reason as :

Caused by: java.lang.NullPointerException.

Any idea on how to fix this? Should I create an intent again in second method? I tried it but no use.. Any suggestions or fixes for this??

Answer 1

For anyone who has similar issue...

The AlarmManager has to be initialized again in the method that your use to deactivate it. Need to Create a Pending intent as well.

Also, make sure that you create the same pending intent(name and attributes) that you used to activate or set repeating alarm. Then, cancel it. All credits to @joey chong

Hope it helps..