Android SurfaceHolder.unlockCanvasAndPost() does not cause redraw

Question

I\'m implementing a fairly standard app with the Android sdk that involves drawing using the SurfaceView, SurfaceHolder, Callback setup.

In my main thread (UI thread) I

Answer 1

That's not how SurfaceView works. Calling unlockCanvasAndPost() does not invoke onDraw(), that's the whole point of using a SurfaceView. A SurfaceView's surface lives in a different window.

Answer 2

So it turns out that when using SurfaceView you draw to a Surface that is underneath a Window. I was setting the background color of the View in xml; it turns out that sets the background color of the Window, not the Surface. In effect, I made the Window opaque so that you couldn't see the Surface underneath.

Lesson Learned.

Answer 3

This is old, but I have a feeling the problem is there is no surfaceholder callback. He was trying to draw on the surface before the surface was created