How to use CPU to perform any operation in Deep Sl

问题:

I'm new in android. I struggle with my application approximately 3 weeks. I need sent and receive packets in normal mode and sleep mode. My app must exchange data a 5 seconds. I tried using alarmmanager but on android 5 it's not works. On android 5 an interval changes it on 60 seconds. Such a solution makes the battery wears out quickly. When I use normal asynctask, not IntentService, then it works only when screen is ON and app is visible. When app is hidden or I click power OFF then exchange data stops working. What is the best solutions?

回答1:

Even RTC_WAKEUP doesn't help most of the times.

Solution that worked for my app when device in deep sleep mode:
Use WakefulBroadcastReceiver combined with AlarmManager.

Service is started by startWakefulService() and when it is finished, it releases the wake lock by calling completeWakefulIntent(intent). So the device will be allowed to go back to sleep.

I'm not adding any code. Search for examples on how to use WakefulBroadcastReceiver with AlarmManager. Even WakefulBroadcastReceiver doc has some template code.

Also reduce the frequency of alarm so you can avoid draining so much battery.

回答2:

You can use the AlarmManager class to wake up the device at a particular time, then fire off an operation at whatever interval you'd like. Code from the docs found here:

private AlarmManager alarmMgr;
private PendingIntent alarmIntent;
...
alarmMgr = (AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(context, AlarmReceiver.class);
alarmIntent = PendingIntent.getBroadcast(context, 0, intent, 0);

// Set the alarm to start at 8:30 a.m.
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(System.currentTimeMillis());
calendar.set(Calendar.HOUR_OF_DAY, 8);
calendar.set(Calendar.MINUTE, 30);

// setRepeating() lets you specify a precise custom interval--in this case,
// 20 minutes.
alarmMgr.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(),
1000 * 60 * 20, alarmIntent);

Notice the last line of this block. You can use the method setRepeating() to set whatever interval you'd like.