on android 4.2.2, if canvas is repeatedly repainted, which calls
clearRect() very often, it may cause the canvas to crash.
This may reproduce if you implement something like a reader, when you mimic dragging the content, which have to call
clearRect(), rather than passing the real size of canvas, you should pass bigger size.
in common case, you just call:
clearRect(0, 0, width, height)
but for something like Android4.2.2:
you should do something like:
clearRect(0, 0, width + 1, height + 1);