如何调暗父UIView(50%透明)登录？

Question

我有一个登录按钮的视图.单击该按钮时,我添加了一个包含用于登录的字段的视图.发生这种情况时,我需要调暗父视图.我怎么做的？

Answer 1

斯威夫特2

UIViews有一个名为的财产maskView.

maskView将永远位于拥有它的UIView之上.

所以,你的方法应该是这样的(这适用于Swift,但它很容易转换为Obj-c):

self.view.maskView = UIView(frame: self.view.frame)
self.view.maskView?.backgroundColor = UIColor.blackColor().colorWithAlphaComponent(0.5)

//Do your work here, block UI, anything you need to, and then...          
self.view.maskView = nil

斯威夫特3

属性名称已更改为mask.

self.view.mask = UIView(frame: self.frame)
self.view.mask?.backgroundColor = UIColor.black.withAlphaComponent(0.5)

//Do your work here, block UI, anything you need to, and then...
self.view.mask = nil

Answer 2

在父视图上添加UIView,该视图最初是透明的,背景颜色为黑色.当您需要调暗它时,将视图的alpha更改为0.5.这将是50%透明.