UIButton 的 alpha 设置为 0.0 时会被禁用吗? [英] Does UIButton become disabled when its alpha is set to 0.0?

问题描述

我的应用中有几个按钮的 alpha 当前设置为零.这些按钮完全没有响应，但是一旦我增加它们的 alpha，它们就会开始响应.这是预期的行为吗?

I have a few buttons in my app whose alpha is currently set to zero. These buttons are completely non-responsive, but as soon as I increase their alpha, they begin to respond. Is this expected behavior?

推荐答案

根据 Apple 的文档，用于 UIView 的 hitTest:withEvent: 方法:

As per Apple's documentation for UIView's hitTest:withEvent: method:

此方法忽略隐藏的、已禁用的视图对象用户交互，或者 alpha 水平小于 0.01.

This method ignores view objects that are hidden, that have disabled user interactions, or have an alpha level less than 0.01.

因此，任何 alpha 低于 0.01 的 UIView 都将被触摸事件处理系统忽略，即不接收触摸.

So any UIView that has alpha lower than 0.01 will be ignored by the touch events processing system, i.e. will not receive touch.

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