Trying to make a canvas that works using MotionEvent.ACTION_MOVE. However after the thread is started horizontal lines draw correctly, but none of the other lines work or are sporadic. As soon as I release the event, the lines clear themselves.
[Edit] It was because the canvas was nested in a ScrollView.
The only thing I can think of that "could" cause that is that you are placing the SurfaceView in a layout that's trying to scroll.
Please post your layout code for a better answer.