视图的 hidden = yes 和 alpha = 0.0f 有什么区别

问题描述

我有一个关于 UIView 的问题，隐藏视图、alpha 视图和不透明视图之间有什么区别?

I have a question about UIView, what's the difference between views hidden, alpha and opaque?

设置view的效果:hidden = yes和view.alpha = 0.0f是一样的.

The effect of setting view: hidden = yes and view.alpha = 0.0f is the same.

推荐答案

差异很微妙.根据 UIView 类参考:

• opaque 告诉系统视图没有透明度，因此渲染速度更快，因为可以跳过混合计算
• hidden 是布尔属性，它仅更改当前视图的可见性并将其从 ui 事件中隐藏.
• alpha 是一个动画属性

• opaque tells the system that the view has no transparency and is thus faster to render because calculations for blending can be skipped
• hidden is boolean property that changes only the visibility of the current view and hides it from ui events.
• alpha is an animatable property

设置 alpha = 0.0f 或 hidden = YES 具有相同的视觉效果.然而，当您有大量嵌套视图时，使用 hidden 不仅在图形意义上而且从 ui 事件中实际隐藏视图可能会导致更有效的响应者链.

Setting alpha = 0.0f or hidden = YES has the same visual effect.However using hidden to actually hide a view not only in a graphical sense but also from ui events might result in a more efficient responder chain when you have lots of nested views.

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