android - How to keep alarms after device was restarted -

i wanna make simple alarm clock. , know after restarting alarms cleared. how can keep alarms after device restarted? how set alarm:

button button = (button) findviewbyid(r.id.button1);         final timepicker timepicker1 = (timepicker) findviewbyid(r.id.timepicker1);         final intent intent1 = new intent(mainactivity.this,myreceiver.class);         button.setonclicklistener(new view.onclicklistener() {             @override             public void onclick(view v) {                 calendar calendar1 = calendar.getinstance();                 calendar1.set(calendar.minute, timepicker1.getcurrentminute());                 calendar1.set(calendar.hour_of_day,timepicker1.getcurrenthour());                 alarmmanager = (alarmmanager) getsystemservice(alarm_service);                 pendingintent pi1 =pendingintent.getbroadcast(mainactivity2.this,0,intent1,0);                 am.set(alarmmanager.rtc,calendar1.gettimeinmillis(),pi1);             }         }); 

save alarms want have , create receiver sets them @ boot.

android broadcastreceiver on startup - keep running when activity in background