title: android:why the method offsetTopandBottom() doesn't call the onDraw()?
body: <p>I have a guess about it, but don't know if it's right.I think this is because method <code>offsetTopandBottom()</code> has just changed the property of view,which is ok just within gpu.If the contents of view changed, then it will call the callbacks,such as <code>onLayout()</code>,<code>onMeasure()</code>,<code>onDraw()</code>,etc.Is that right?</p>