how to wakeup android phone from sleep?

Question

How to wakeup android phone from sleep (suspend to mem) programmably? I don\'t want to acquire any wakelock, which means the phone goes into \"real\" sleep with the cpu disabled

Answer 1

I just wrote an application which can do this, here is some example code: First, I create an AlarmManager and set an alarm for a specific time:

AlarmManager manager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 15);
calendar.set(Calendar.MINUTE, 30);
calendar.set(Calendar.SECOND, 0);
// if the time is before now then add one day to it
if(calendar.getTimeInMillis() < System.currentTimeMillis())
   calendar.setTimeInMillis(calendar.getTimeInMillis()+86400000);
manager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), 0);

I need a BroadcastReciever to recieve this alarm. For this I have to put into my manifest:

<application ...>
    <receiver android:name="hu.bendaf.example.AlarmReceiver"/>
...
</application>

and I also have the AlarmReciever class, which starts my main Activity on recieve:

public class AlarmReceiver extends BroadcastReceiver {
    public static final String WAKE = "Wake up";
    @Override
    public void onReceive(Context context, Intent intent) {
        //Starting MainActivity
        Intent myAct = new Intent(context, MainActivity.class);
        myAct.putExtra(WAKE, true);
        myAct.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(myAct);
    }
}

and in my Activity's onCreate function I have:

// Wake up phone if needed
if(getIntent().hasExtra(AlarmReceiver.WAKE) && getIntent().getExtras().getBoolean(AlarmReceiver.WAKE)){
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD |
                        WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED |
                        WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON,
                        WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD |
                        WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED |
                        WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);
}

This code wakes up my phone at next 15:30:00 (either it is today or tomorrow).

Answer 2

In order to let the Activity wake up the device and not require a password/swipe, you only need to add a few flags. To get that, include to your code:

this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN |
    WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD |
    WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED |
    WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON,
    WindowManager.LayoutParams.FLAG_FULLSCREEN |
    WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD |
    WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED |
    WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);

This will wake up your App activity.

Answer 3

Use AlarmManager to broadcast an Intent at the time you want to do some work and have the device wake up. In the BroadcastReceiver, either do the work you need to do (if it is short), or obtain a WakeLock (probably via a singleton), start a service, have the service do the work, then have the service release the WakeLock.

You can read about that here: https://groups.google.com/forum/#!topic/android-developers/5--QRAPlFL0