Swift：递归循环遍历所有子视图以查找特定类并附加到数组

Question

花时间试图弄清楚这一点。我在这里问了一个类似的问题：Swift: Get all subviews of a specific type and add to an array

虽然这可行，但我意识到有很多子视图和子子视图，所以我需要一个从主 UIView 开始的函数，循环遍历所有子视图（及其子视图，直到没有任何剩余）和将其添加到我命名为 CheckCircle 的自定义按钮类的数组中。

基本上，我希望得到一个 CheckCircles 数组，它们构成以编程方式添加到该视图的所有 CheckCircles。

有什么想法吗？这是我一直在做的事情。它似乎没有将任何 Checkcircles 附加到数组中：

    func getSubviewsOfView(v:UIView) -> [CheckCircle] {
        var circleArray = [CheckCircle]()
        // Get the subviews of the view

        var subviews = v.subviews

        if subviews.count == 0 {
            return circleArray
        }

        for subview : AnyObject in subviews{
  if let viewToAppend = subview as? CheckCircle {
        circleArray.append(viewToAppend as CheckCircle)
      }
            getSubviewsOfView(subview as! UIView)
        }
        return circleArray
    }

Answer 1

基于 Aaron Brager 和 ullstrm 的答案

详情

• Xcode 9.1，Swift 4，
• Xcode 版本 10.3 (10G8)，Swift 5

解决方案

extension UIView {

    class func getAllSubviews<T: UIView>(from parenView: UIView) -> [T] {
        return parenView.subviews.flatMap { subView -> [T] in
            var result = getAllSubviews(from: subView) as [T]
            if let view = subView as? T { result.append(view) }
            return result
        }
    }

    class func getAllSubviews(from parenView: UIView, types: [UIView.Type]) -> [UIView] {
        return parenView.subviews.flatMap { subView -> [UIView] in
            var result = getAllSubviews(from: subView) as [UIView]
            for type in types {
                if subView.classForCoder == type {
                    result.append(subView)
                    return result
                }
            }
            return result
        }
    }

    func getAllSubviews<T: UIView>() -> [T] { return UIView.getAllSubviews(from: self) as [T] }
    func get<T: UIView>(all type: T.Type) -> [T] { return UIView.getAllSubviews(from: self) as [T] }
    func get(all types: [UIView.Type]) -> [UIView] { return UIView.getAllSubviews(from: self, types: types) }
}

使用示例

var allViews = UIView.getAllSubviews(from: simpleView)
func printResult(with text: String) {
    print("\n==============================================")
    print("\(text):\n\(allViews.map { $0.classForCoder } )")
}
printResult(with: "UIView.getAllSubviews(from: simpleView)")

allViews = UIView.getAllSubviews(from: simpleView) as [UILabel]
printResult(with: "UIView.getAllSubviews(from: simpleView) as [UILabel]")

allViews = UIView.getAllSubviews(from: simpleView, types: [UIStackView.self, UILabel.self])
printResult(with: "UIView.getAllSubviews(from: simpleView, types: [UIStackView.self, UILabel.self])")

allViews = simpleView.getAllSubviews()
printResult(with: "simpleView.getAllSubviews()")

allViews = simpleView.getAllSubviews() as [UILabel]
printResult(with: "simpleView.getAllSubviews() as [UILabel]")

allViews = simpleView.get(all: UILabel.self)
printResult(with: "simpleView.get(all: UILabel.self)")

allViews = simpleView.get(all: [UIStackView.self, UILabel.self])
printResult(with: "simpleView.get(all: [UIStackView.self, UILabel.self])")

样本输出

==============================================
UIView.getAllSubviews(from: simpleView):
[UILabel, UIButton, UILabel, UILabel, UILabel, UIStackView]

==============================================
UIView.getAllSubviews(from: simpleView) as [UILabel]:
[UILabel, UILabel, UILabel, UILabel]

==============================================
UIView.getAllSubviews(from: simpleView, types: [UIStackView.self, UILabel.self]):
[UILabel, UILabel, UILabel, UILabel, UIStackView]

==============================================
simpleView.getAllSubviews():
[UILabel, UIButton, UILabel, UILabel, UILabel, UIStackView]

==============================================
simpleView.getAllSubviews() as [UILabel]:
[UILabel, UILabel, UILabel, UILabel]

==============================================
simpleView.get(all: UILabel.self):
[UILabel, UILabel, UILabel, UILabel]

==============================================
simpleView.get(all: [UIStackView.self, UILabel.self]):
[UILabel, UILabel, UILabel, UILabel, UIStackView]

样本故事板

其他信息

另外，我建议使用弱引用。 Array with weak references to objects

Answer 2

基于 Vasily Bodnarchuk、Aaron Brager 和 ullstrm 的回答。

为什么是另一个？

我个人不喜欢 as [XXX] 和 let specific: [Type]，而是将类型传递给函数调用，例如

let scrollViews = view.getNestedSubviews(ofType: UIScrollView.self)
print(scrollViews) // outputs: [UIScrollView]

我还将All 重命名为Nested，因为它可以更好地向 API 调用者传达函数的递归性质。

详情

Swift 4.x、Xcode 9.1+

解决方案

extension UIView {

    class func getNestedSubviews<T: UIView>(view: UIView) -> [T] {
        return view.subviews.flatMap { subView -> [T] in
            var result = getNestedSubviews(view: subView) as [T]
            if let view = subView as? T {
                result.append(view)
            }
            return result
        }
    }

    func getNestedSubviews<T: UIView>() -> [T] {
        return UIView.getNestedSubviews(view: self) as [T]
    }
}

用法

let scrollViews = view.getNestedSubviews(ofType: UIScrollView.self)
print(scrollViews) // outputs: [UIScrollView]

Answer 3

你可以通过扩展 UIView 并定义以下函数来实现它。

Swift4 代码

extension UIView {
    func findViews<T: UIView>(subclassOf: T.Type) -> [T] {
        return recursiveSubviews.compactMap { $0 as? T }
    }

    var recursiveSubviews: [UIView] {
        return subviews + subviews.flatMap { $0.recursiveSubviews }
    }
}

用法

findViews(subclassOf: UILabel.self)
findViews(subclassOf: CheckCircle.self)

Answer 4

UITextField 不再在子视图的顶层，所以我使用这种方法：

@implementation UISearchBar (changeFont)

- (void)setFont:(UIFont *)font {
    for (UIView *v in [self subviews]) {
        if ([v isKindOfClass:[UITextField class]]) {
            UITextField *tf = (UITextField *)v;
            tf.font = font;
            UILabel *l = (UILabel *)[tf valueForKey:@"placeholderLabel"];
            l.font = font;
            break;
        } else if (v.subviews.count) {
            for (UIView *v1 in v.subviews) {
                if ([v1 isKindOfClass:[UITextField class]]) {
                    UITextField *tf = (UITextField *)v1;
                    tf.font = font;
                    UILabel *l = (UILabel *)[tf valueForKey:@"placeholderLabel"];
                    l.font = font;
                    break;
                } else if (v1.subviews.count) {
                    for (UIView *v2 in v1.subviews) {
                        if ([v2 isKindOfClass:[UITextField class]]) {
                            UITextField *tf = (UITextField *)v2;
                            tf.font = font;
                            UILabel *l = (UILabel *)[tf valueForKey:@"placeholderLabel"];
                            l.font = font;
                            break;
                        }
                    }
                }
            }
        }
    }
}

有点啰嗦，但应该考虑到文本字段将来会更深入

Answer 5

我使用 swift 3 和泛型的方法！

private func getSubviewsOf<T: UIView>(view: UIView) -> [T] {
    var subviews = [T]()

    for subview in view.subviews {
        subviews += getSubviewsOf(view: subview) as [T]

        if let subview = subview as? T {
            subviews.append(subview)
        }
    }

    return subviews
}

要获取视图层次结构中的所有 UILabel，只需执行以下操作：

let allLabels: [UILabel] = getSubviewsOf(view: theView)

Answer 6

您的主要问题是，当您调用 getSubviewsOfView(subview as! UIView)（在函数内递归）时，您没有对结果做任何事情。

您也可以删除count == 0 检查，因为在这种情况下，for…in 循环将被跳过。你还有一堆不必要的演员表

假设您希望获得CheckCircle 实例的平面数组，我认为您的代码的这种改编应该可以工作：

func getSubviewsOfView(v:UIView) -> [CheckCircle] {
    var circleArray = [CheckCircle]()

    for subview in v.subviews as! [UIView] {
        circleArray += getSubviewsOfView(subview)

        if subview is CheckCircle {
            circleArray.append(subview as! CheckCircle)
        }
    }

    return circleArray
}