/*
* Draw traversal performs several drawing steps
which must be executed
* in the appropriate order:
*
* 1. Draw the background
*
2. If necessary, save the canvas‘ layers to prepare for fading
* 3. Draw view‘s content
* 4. Draw
children
* 5. If necessary, draw the fading edges
and restore layers
* 6. Draw decorations
(scrollbars for instance)
*/
// Step 1, draw the background, if needed
// Step 3, draw the content
if (!dirtyOpaque)
onDraw(canvas);
// Step 4, draw the children
dispatchDraw(canvas);
// Step 6, draw decorations (scrollbars)
onDrawScrollBars(canvas);
onDraw():When custom a view, overriding this method
measure(内部调用onMeasure)
layout(内部调用onLayout)
draw(内部调用ondraw)
处理组件的布局通常要重写onMesure和onLayout这两个方法
Reference:
http://blog.csdn.net/czh0766/article/details/5790295
http://blog.csdn.net/scorplopan/article/details/6302827
android draw() onDraw() dispathDraw() onDrawScrollBars,布布扣,bubuko.com