1.draw the backgroud
2.if nessary,save the canvas` layers to prepare for fading
3.draw view`s content
4.draw children
5.if nessary,draw the fading edges
6.draw decorations(scrollbars for instance)
android绘制流程
原文：https://www.cnblogs.com/l-h-h/p/10321770.html
