This one:
Allows an application to open windows using the type
TYPE_SYSTEM_ALERT, shown on top of all other applications.
Very few applications should use this permission; these windows are intended
for system-level interaction with the user.Constant Value: “android.permission.SYSTEM_ALERT_WINDOW”
//EDIT:
The full code here:
public class ChatHeadService extends Service {
private WindowManager windowManager;
private ImageView chatHead;
@Override public IBinder onBind(Intent intent) {
// Not used
return null;
}
@Override public void onCreate() {
super.onCreate();
windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
chatHead = new ImageView(this);
chatHead.setImageResource(R.drawable.android_head);
WindowManager.LayoutParams params = new WindowManager.LayoutParams(
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.WRAP_CONTENT,
WindowManager.LayoutParams.TYPE_PHONE,
WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
PixelFormat.TRANSLUCENT);
params.gravity = Gravity.TOP | Gravity.LEFT;
params.x = 0;
params.y = 100;
windowManager.addView(chatHead, params);
}
@Override
public void onDestroy() {
super.onDestroy();
if (chatHead != null) windowManager.removeView(chatHead);
}
}
Don’t forget to start the service somehow:
startService(new Intent(context, ChatHeadService.class));
.. And add this service to your Manifest.