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Added in API level 1

Summary: Methods | [Expand All]

public static interface ViewTreeObserver.OnPreDrawListener

android.view.ViewTreeObserver.OnPreDrawListener

Known Indirect Subclasses

当将要绘制视图树时调用回调的接口定义。

Public methods
`abstract boolean`	`onPreDraw()` 将在将要绘制视图树时调用回调方法。

Added in API level 1

boolean onPreDraw ()

将在将要绘制视图树时调用回调方法。此时，树中的所有视图都被测量并给出一帧。客户可以使用它来调整它们的滚动范围，甚至可以在绘图之前请求新的布局。

Returns
`boolean`	Return true to proceed with the current drawing pass, or false to cancel.

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