Android : Widget for switch on camera flashlight

I've see that there's a lot of torch app that offer also a widget for switch on flashlight. I'm trying to do my own widget for perform the same task, but i have some questions. I've already an app for switch on and off camera flashlight, but it use a hidden surfaceView inside layout for do that (flashlight doesn't switch on without surfaceView). Now, as i could read from developer site, SurfaceView is not admitted inside widget layout. What's the correct way to implement this kind of widget?