Android Studio AlarmManager.cancel() closes the App

Question

I am making an alarm app in which the alarm can be set with a toggle button. The code works in ADV , but if I test it on a real device, the the App closes imediatly after settting the alarm once and then turning it off. Also the alarm does not turn off.

(button press alarmOn -> alarm is on, button press alarmOff-> app closes + alarm is still on)

mStartBtn1.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                AlarmManager am = (AlarmManager) getSystemService(ALARM_SERVICE);
                long time;
                if (((ToggleButton) view).isChecked()){ //if button is on
                    Intent intent = new Intent(MainActivity.this, AlarmReceiverActivity.class);
                    PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this, 2, intent, PendingIntent.FLAG_CANCEL_CURRENT);

                    Calendar calendar = Calendar.getInstance();
                    calendar.set(Calendar.HOUR_OF_DAY, timePicker1.getCurrentHour());
                    calendar.set(Calendar.MINUTE, timePicker1.getCurrentMinute());

                    time = (calendar.getTimeInMillis() - (calendar.getTimeInMillis() % 60000));
                    if (System.currentTimeMillis() > time) {
                        if (calendar.AM_PM == 0)
                            time = time + (1000 * 60 * 60 * 12);
                        else
                            time = time + (1000 * 60 * 60 * 24);
                    }
                    am.set(AlarmManager.RTC_WAKEUP, time, pendingIntent); //sets the alarm
                }else{ //if button is off
                    am.cancel(pendingIntent);
                }
            }
        });

Thank you for helping,

Florian

Answer 1

Your app is basically crashing. Maybe because you are passing null to am.cancel(pendingIntent) //pendingIntent might be null here.

Try moving PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this, 2, intent, PendingIntent.FLAG_CANCEL_CURRENT); outside the if condition. If that is not the case then check AlarmReceiverActivity for crashes.