如何更改尺寸时，如何强制重绘（drawRect）SubView？ [英] How Do I Force Redrawing (drawRect) of a SubView When it Changes Dimensions?

问题描述

我有一个UIView，它包含一行 UIView 的子类。子类已重写 drawRect ：并已设置 contentMode = UIViewContentModeRedraw 。

I have a UIView that contains a row of subclasses of UIView. The subclass has overridden drawRect: and has set contentMode = UIViewContentModeRedraw.

当用户压扁并拉伸父容器时，子视图挤压和拉伸。当形状发生变化时，我希望重复调用 drawRect 来更改子视图的内容。到目前为止，我一直没有成功。这样做的正确方法是什么？

As the user squashes and stretches the parent container the child views squash and stretch. As the shape change occurs I would like to have drawRect called repeatedly to change the contents of the child views. So far I have been unsuccessful. What is the correct way to do this?

干杯，

Doug

推荐答案

在Cocoa中，您很少（如果曾经）调用drawRect - 您只需将区域或视图标记为需要更新，它将被安排重新绘制。这允许将多个失效的重绘折叠在一起。

In Cocoa, you rarely (if ever) call drawRect - you just mark the region or view as needing update, and it will be scheduled for redrawing. This allows redraws for multiple invalidations to be collapsed together.

对于Cocoa Touch，您需要 [view setNeedsDisplay] 或 setNeedsDisplayinRect：（CGRect）

For Cocoa Touch, you want either [view setNeedsDisplay], or setNeedsDisplayinRect:(CGRect)

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