Android draw、onDraw、dispatchDraw、invalidate、computeScroll 一些简要说明
View中:publicvoiddraw(Canvascanvas){/*1.Drawthebackground 绘制背景2.Ifnecessary,savethecanvas'layerstoprepareforfading 如有必要,颜色渐变淡之前保存画布层(即锁定原有的画布内容)3.Drawview'scontent 绘制view的内容4.Drawchildren 绘制子view5.Ifn