How do I lock the screen?

[somethingjava]

I'm trying to create an app and I'm nearly complete. I have been trying to figure out how to either put the phone into sleep mode, which would also lock the screen or just lock the screen.

This is how I am currently trying to accomplish this using the PowerManager.

    	try{
	    	PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
	    	PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK | PowerManager.ON_AFTER_RELEASE, "FACEDOWN_LOCK");
	    	wl.acquire();
	    		// ? Perform operations
	    		pm.goToSleep(SystemClock.uptimeMillis());
	    	wl.release();
    	}catch(Exception e){
    		 Toast.makeText(this, e.getMessage() , 10000).show();
    	}

This does NOT work. It gives me permission problems even though my app is signed and I have the permissions enabled in the manifest.xml

    <permission android:name="android.permission.WAKE_LOCK" />
    <permission android:name="android.permission.DEVICE_POWER" />
	<uses-permission android:name="android.permission.WAKE_LOCK" /> 
	<uses-permission android:name="android.permission.DEVICE_POWER" />

Is there a proper way to do this? Can it even be done? Any help would be awesome. I've spent a better part of 8 hours in research alone and I have not been able to find any solution as to how you get the phone to lock or go to sleep.


Thanks,
Marco