Android -- View流程

在自定义view中打log，view的显示共有三种，visible、invisible和gone，分别看一下log：

gone

onVisibilityChanged
construct 2 parameters
onFinishInflate
onVisibilityChanged
onVisibilityChanged
onRtlPropertiesChanged
onRtlPropertiesChanged
onAttachedToWindow
onWindowVisibilityChanged
onWindowFocusChanged

invisible

onVisibilityChanged
construct 2 parameters .
onFinishInflate
onVisibilityChanged
onVisibilityChanged
onRtlPropertiesChanged
onRtlPropertiesChanged
onAttachedToWindow
onWindowVisibilityChanged
onMeasure , width : 1080  ; height: 1557
onMeasure , width : 144  ; height: 1500
onSizeChanged
onLayout --> l: 0  ; r : 144  ; t: 57  ; b: 201  : changed :true
onMeasure , width : 1080  ; height: 1557
onMeasure , width : 144  ; height: 1500
onLayout --> l: 0  ; r : 144  ; t: 57  ; b: 201  : changed :false
onWindowFocusChanged

visible

construct 2 parameters .
onFinishInflate
onVisibilityChanged
onVisibilityChanged
onRtlPropertiesChanged
onRtlPropertiesChanged
onAttachedToWindow
onWindowVisibilityChanged
onMeasure , width : 1080  ; height: 1557
onMeasure , width : 144  ; height: 1500
onSizeChanged
onLayout --> l: 0  ; r : 144  ; t: 57  ; b: 201  : changed :true
onMeasure , width : 1080  ; height: 1557
onMeasure , width : 144  ; height: 1500
onLayout --> l: 0  ; r : 144  ; t: 57  ; b: 201  : changed :false
onDraw
onWindowFocusChanged

1、从中看到view默认为可见的，不是默认值时先调用 onVisibilityChanged ，但是此时该view的任何位置信息都不知道。

2、可见性改变后才是调用带有两个参数的构造函数

3、从xml 文件中 inflate 完成

4、将view 加到 window 中(View 是gone 的，那么View创建生命周期也就结束)

5、测量view的长宽(onMeasure)

6、定位View在父View中的位置(onLayout)--->(View 是invisible ，View 创建生命周期结束)

7、onDraw(只有可见的View 才在window 中绘制)

setContentView(new View(this))

construct 1 parameter
onVisibilityChanged
onVisibilityChanged
onRtlPropertiesChanged
onRtlPropertiesChanged
onAttachedToWindow
onWindowVisibilityChanged
onMeasure , width : 1080  ; height: 1557
onSizeChanged
onLayout --> l: 0  ; r : 1080  ; t: 0  ; b: 1557  : changed :true
onMeasure , width : 1080  ; height: 1557
onLayout --> l: 0  ; r : 1080  ; t: 0  ; b: 1557  : changed :false
onDraw
onWindowFocusChanged

默认情况下view的长和宽默认和父view的长和宽一致。

销毁

onWindowFocusChanged

onWindowVisibilityChanged

onDetachedFromWindow

总结

View 的关键生命周期为

构造View --> onFinishInflate --> onAttachedToWindow --> onMeasure --> onSizeChanged --> onLayout --> onDraw --> onDetackedFromWindow

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