在 UIView 中循环 UIButtons

Posted 2023-02-24

【中文标题】在 UIView 中循环 UIButtons

【英文标题】：Looping through UIButtons in UIView

【发布时间】：2017-03-06 15:22:37

【问题描述】：

我的设置如下：

UIView(1) -> UIScrollview -> UIStackview -> UIViews(2) -> UIButton

如何遍历 UIStackview 中所有 UIViews(2) 中的每个 UIButton？我的 UIView(1) 中有更多按钮，所以我无法遍历整个 Viewcontroller 中的每个按钮。我试过了：

for view in self.stackview.subviews as [UIView] 
    if let btn = view as? UIButton 
        print("Worked")
    

for view in self.scrollview.subviews as [UIView] 
    if let btn = view as? UIButton 
        print("Worked")
    

for case let button as UIButton in self.scrollview.subviews 
    print("worked")

for case let button as UIButton in self.stackview.subviews 
    print("worked")

尝试在我的 viewDidLoad 函数中添加它时，它只是不打印任何内容。我在这里做错了什么？

【问题讨论】：

for view in self.stackview.subviews as [UIView] if let btn = view as? UIButton print("Worked") else for asubView in view.subviews as [UIView]if let btn = view as? UIButton print("Worked")?

【参考方案1】：

想到的第一个解决方案：

let buttons = self.stackview.subviews // direct subviews of stack view
    .map  subview in subview.subviews  // second level subviews
    .joined() // join the second level subviews into one flat array
    .compactMap  $0 as? UIButton  // filter buttons

基本上你只是忘记跳到第二级。您只迭代第一级子视图。

如果您想要一个更稳定的解决方案，您可以在任何深度递归迭代子视图，例如使用类别：

extension UIView 
    var allSubviews: [UIView] 
        return self.subviews + self.subviews.map  $0.allSubviews .joined()
    

然后

let buttons = self.stackview.allSubviews.compactMap  $0 as? UIButton 

【讨论】：

谢谢，这对于制作 for in 循环非常有用！

很酷的函数式解决方案。 （已投票）

【参考方案2】：

怎么样……

for view in stackView.subviews 
    for case let button as UIButton in view.subviews 
        print(button.title(for: .normal)) // Do something with button
    

或

for case let button as UIButton in stackView.subviews.flatMap( $0.subviews ) 
    print(button.title(for: .normal))  // Do something with button

或

for button in stackView.subviews.flatMap( $0.subviews ).flatMap( $0 as? UIButton ) 
    print(button.title(for: .normal))  // Do something with button