Android Programming Tutorials

Now, Your Friends Are Alarmed

Next, add a couple of private data members, one for an AlarmManager and

one for a PendingIntent, with suitable imports:

private PendingIntent pi=null;

You will need to add an import for android.app.AlarmManager. The

AlarmManager is the gateway to scheduled tasks in Android, while the

PendingIntent will be invoked each time the alarm goes off.

Then, update onCreate() to obtain the AlarmManager system service and to

set up the PendingIntent that AlarmManager should invoke every polling

cycle, plus schedule the initial alarm:

public void onCreate() {

super.onCreate();

registerReceiver(onBatteryChanged,

new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

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

Intent i=new Intent(this, OnAlarmReceiver.class);

pi=PendingIntent.getBroadcast(this, 0 , i, 0 );

setAlarm(INITIAL_POLL_PERIOD);

}

@Override

Note that we also get rid of our statement to schedule the threadBody

Runnable as a background thread, because an IntentService (parent class of

WakefulIntentService) automatically lets us do our work on a background

thread.

This requires a setAlarm() method to actually schedule the alarm:

private void setAlarm(long period) {

alarm.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,

SystemClock.elapsedRealtime()+period,

pi);

}

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