How does ImageView just redraw part of its content when invalidate(Rect) is called?
- by imax366
Hi, guys
I am new to Android development, just reading docs and trying the
APIs. I am quit confused how ImageView managed to draw just a part of
its content after an invalidate(Rect) invocation.
I've checked ImageView.java, found no other drawing method except
onDraw(Canvas), but onDraw(Canvas) only cut the drawable only if it is
beyound the view's visible boundary.
I also read the implementation of View.invalidate(Rect), I think the
key of this function is calling to
mParent.invalidateChild(this, r);
However, I think the parent view doesn't know how to draw the child in
the given Rect, it finally has to call some method of it child to
paint out.
Has anybody investigated this part of codes? Would you please give me
some guide?
