Programmatically turn screen on in android

Question

I am developing an alarm application. From the main activity i set the alarm using broadcast. Then in onReceive in broadcast receiver i call activity that is enabling user to shut down or snooze the alarm...In that activity, in the beginning of onCreate i use this lines to turn screen on and unlock the device:

final Window win = getWindow();
    win.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
                  | WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD); 
    win.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                  | WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON);

This works perfect on Samsung Galaxy S2 with android 2.3.4 but doesnt work on htc with android 2.3.5. On htc it does nothing, and when i press lock button screen automatically unlocks without me draging the circle. Its like flag_dissmiss_keygard is working but flag_turn_screen_on isnt. Is there another way or another solution for doing this?

Answer 1

I started off much like you, and the window flags didn't really work.

I finally got it to work by using two Android services: KEYGUARD_SERVICE and POWER_SERVICE:

KeyguardManager km = (KeyguardManager) context.getSystemService(Context.KEYGUARD_SERVICE);
final KeyguardManager.KeyguardLock kl = km.newKeyguardLock("MyKeyguardLock");
kl.disableKeyguard();

PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
wakeLock = pm.newWakeLock(PowerManager.FULL_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP
        | PowerManager.ON_AFTER_RELEASE, "MyWakeLock");
wakeLock.acquire();

Don't forget to release the wake lock when you're done with it.

You'll need to request permissions DISABLE_KEYGUARD and WAKE_LOCK