View overlay displayed on top of all activities

gistfile1.java

public class OverlayService extends Service {
 
    LinearLayout oView;
 
    @Override
    public IBinder onBind(Intent i) {
        return null;
    }
 
    @Override
    public void onCreate() {
        super.onCreate();
        oView = new LinearLayout(this);  
        oView.setBackgroundColor(0x88ff0000); // The translucent red color
        WindowManager.LayoutParams params = new WindowManager.LayoutParams(
                WindowManager.LayoutParams.MATCH_PARENT,
                WindowManager.LayoutParams.MATCH_PARENT,
                WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,
                0 | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
                PixelFormat.TRANSLUCENT);       
        WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
        wm.addView(oView, params);
    }
     
    @Override
    public void onDestroy() {           
        super.onDestroy();
        if(oView!=null){
            WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
            wm.removeView(oView);
        }
    }
 
}