public class ScreenActivity extends Activity 
{ 
  PowerManager powerManager = null; 
  WakeLock wakeLock = null; 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
   super.onCreate(savedInstanceState); 
   this.setContentView(R.layout.main); 
   powerManager = (PowerManager)this.getSystemService(this.POWER_SERVICE); 
   wakeLock = this.powerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK, "My Lock"); 
  } 
  @Override 
  protected void onResume() { 
   super.onResume(); 
   wakeLock.acquire(); 
  } 
  @Override 
  protected void onPause() { 
   super.onPause(); 
   wakeLock.release(); 
  } 
}