UIAlertController - 将自定义视图添加到操作表

Posted 2023-02-22

【中文标题】UIAlertController - 将自定义视图添加到操作表

【英文标题】：UIAlertController - add custom views to actionsheet

【发布时间】：2015-12-23 18:14:24

【问题描述】：

当我们尝试在屏幕截图中附加图像时，我正在尝试制作操作表，就像它在 ios 上的消息应用程序中显示的那样。

我意识到在新的 UIAlertController 中，我们无法容纳任何自定义视图。有什么办法可以做到这一点？

我的代码看起来很标准。

    let alertController = UIAlertController(title: "My AlertController", message: "tryna show some images here man", preferredStyle: UIAlertControllerStyle.ActionSheet)

        let okAction = UIAlertAction(title: "oks", style: .Default)  (action: UIAlertAction) -> Void in
        alertController.dismissViewControllerAnimated(true, completion: nil)
    
    let cancelAction = UIAlertAction(title: "Screw it!", style: .Cancel)  (action: UIAlertAction) -> Void in
        alertController.dismissViewControllerAnimated(true, completion: nil)
    

    alertController.addAction(okAction)
    alertController.addAction(cancelAction)

    self.presentViewController(alertController, animated: true, completion: nil)

【参考方案1】：

UIAlertController 扩展了 UIViewController，它有一个 view 属性。您可以根据自己的意愿向该视图添加子视图。唯一的麻烦是正确调整警报控制器的大小。你可以做这样的事情，但这很容易在下次 Apple 调整 UIAlertController 的设计时中断。

斯威夫特 3

    let alertController = UIAlertController(title: "\n\n\n\n\n\n", message: nil, preferredStyle: UIAlertControllerStyle.actionSheet)

    let margin:CGFloat = 10.0
    let rect = CGRect(x: margin, y: margin, width: alertController.view.bounds.size.width - margin * 4.0, height: 120)
    let customView = UIView(frame: rect)

    customView.backgroundColor = .green
    alertController.view.addSubview(customView)

    let somethingAction = UIAlertAction(title: "Something", style: .default, handler: (alert: UIAlertAction!) in print("something"))

    let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: (alert: UIAlertAction!) in print("cancel"))

    alertController.addAction(somethingAction)
    alertController.addAction(cancelAction)

    DispatchQueue.main.async 
        self.present(alertController, animated: true, completion:)
    

斯威夫特

let alertController = UIAlertController(title: "\n\n\n\n\n\n", message: nil, preferredStyle: UIAlertControllerStyle.actionSheet)

let margin:CGFloat = 10.0
let rect = CGRect(x: margin, y: margin, width: alertController.view.bounds.size.width - margin * 4.0, height: 120)
let customView = UIView(frame: rect)

customView.backgroundColor = .green
alertController.view.addSubview(customView)

let somethingAction = UIAlertAction(title: "Something", style: .default, handler: (alert: UIAlertAction!) in print("something"))

let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: (alert: UIAlertAction!) in print("cancel"))

alertController.addAction(somethingAction)
alertController.addAction(cancelAction)

self.present(alertController, animated: true, completion:)

Objective-C

  UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"\n\n\n\n\n\n" message:nil preferredStyle:UIAlertControllerStyleActionSheet];

  CGFloat margin = 8.0F;
  UIView *customView = [[UIView alloc] initWithFrame:CGRectMake(margin, margin, alertController.view.bounds.size.width - margin * 4.0F, 100.0F)];
  customView.backgroundColor = [UIColor greenColor];
  [alertController.view addSubview:customView];

  UIAlertAction *somethingAction = [UIAlertAction actionWithTitle:@"Something" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) ];
  UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) ];
  [alertController addAction:somethingAction];
  [alertController addAction:cancelAction];
  [self presentViewController:alertController animated:YES completion:^];

话虽如此，一个更简单的方法是创建您自己的视图子类，其工作方式类似于 UIAlertController 的 UIAlertActionStyle 布局。事实上，相同的代码在 iOS 8 和 iOS 9 中看起来略有不同。

iOS 8

iOS 9

iOS 10

【讨论】：

这太棒了，真的很有帮助，我仍然在边缘的绿色视图后面看到一条线。我想我会为此在绿色视图周围放置一个容器视图。 0 边距。

谢谢，伙计。这太棒了。只是稍微调整了自定义视图的宽度，但一切都很好！干杯。

我的 Objective C 答案仍然可以正常工作。 Swift 答案使用旧语法，但现在已针对 Swift 3.0 进行了更新，感谢@palme。

这就是为什么我在回答中提到“一种更简单的方法是创建自己的视图子类，其工作方式类似于 UIAlertController 的 UIAlertActionStyle 布局。事实上，相同的代码在 iOS 8 中看起来略有不同和 iOS 9。”问题是将子视图添加到 UIAlertController，这是公认的答案。

我相信 UIAlertController 的初始帧大小与 UIView 相同。在 iPhone 上，上面的代码可以正常工作，因为 alertController 占据了设备的整个宽度。在 iPad 上调整了 alertController 的大小。要使子视图自动调整大小，请设置调整大小掩码 customView.autoresizingMask = UIViewAutoresizingFlexibleWidth;

【参考方案2】：

到目前为止我发现的最干净的解决方案是使用 AutoLayout 约束：

func showPickerController() 
    let alertController = UIAlertController(title: "Translation Language", message: nil, preferredStyle: .actionSheet)
    let customView = UIView()
    alertController.view.addSubview(customView)
    customView.translatesAutoresizingMaskIntoConstraints = false
    customView.topAnchor.constraint(equalTo: alertController.view.topAnchor, constant: 45).isActive = true
    customView.rightAnchor.constraint(equalTo: alertController.view.rightAnchor, constant: -10).isActive = true
    customView.leftAnchor.constraint(equalTo: alertController.view.leftAnchor, constant: 10).isActive = true
    customView.heightAnchor.constraint(equalToConstant: 250).isActive = true

    alertController.view.translatesAutoresizingMaskIntoConstraints = false
    alertController.view.heightAnchor.constraint(equalToConstant: 430).isActive = true

    customView.backgroundColor = .green

    let selectAction = UIAlertAction(title: "Select", style: .default)  (action) in
        print("selection")
    

    let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
    alertController.addAction(selectAction)
    alertController.addAction(cancelAction)
    self.present(alertController, animated: true, completion: nil)

输出：

【讨论】：

这是最好的答案 - 不是被“挑选”的答案我很高兴有人正确地做到了这一点:-)

关于该主题的最佳答案。想知道为什么这里不接受这个答案。

如果对话框在某些情况下有标题，它会中断。根据标题长度和用户字体大小偏好，标题可以与自定义视图重叠。应计算顶部填充。没有太多ios经验，否则会发布解决方案。

【参考方案3】：

我为 UIAlertController（在 Swift 4 中）编写了一个扩展，它解决了自动布局的布局问题。甚至还有一个备用消息字符串以防万一（由于 UIAlertController 布局的未来更改）。

import Foundation

extension UIAlertController 
    
    /// Creates a `UIAlertController` with a custom `UIView` instead the message text.
    /// - Note: In case anything goes wrong during replacing the message string with the custom view, a fallback message will
    /// be used as normal message string.
    ///
    /// - Parameters:
    ///   - title: The title text of the alert controller
    ///   - customView: A `UIView` which will be displayed in place of the message string.
    ///   - fallbackMessage: An optional fallback message string, which will be displayed in case something went wrong with inserting the custom view.
    ///   - preferredStyle: The preferred style of the `UIAlertController`.
    convenience init(title: String?, customView: UIView, fallbackMessage: String?, preferredStyle: UIAlertController.Style) 
        
        let marker = "__CUSTOM_CONTENT_MARKER__"
        self.init(title: title, message: marker, preferredStyle: preferredStyle)
        
        // Try to find the message label in the alert controller's view hierarchie
        if let customContentPlaceholder = self.view.findLabel(withText: marker),
            let customContainer =  customContentPlaceholder.superview 
            
            // The message label was found. Add the custom view over it and fix the autolayout...
            customContainer.addSubview(customView)
            
            customView.translatesAutoresizingMaskIntoConstraints = false
            customContainer.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-[customView]-|", options: [], metrics: nil, views: ["customView": customView]))
            customContainer.addConstraint(NSLayoutConstraint(item: customContentPlaceholder,
                                                             attribute: .top,
                                                             relatedBy: .equal,
                                                             toItem: customView,
                                                             attribute: .top,
                                                             multiplier: 1,
                                                             constant: 0))
            customContainer.addConstraint(NSLayoutConstraint(item: customContentPlaceholder,
                                                             attribute: .height,
                                                             relatedBy: .equal,
                                                             toItem: customView,
                                                             attribute: .height,
                                                             multiplier: 1,
                                                             constant: 0))
            customContentPlaceholder.text = ""
         else  // In case something fishy is going on, fall back to the standard behaviour and display a fallback message string
            self.message = fallbackMessage
        
    


private extension UIView 
    
    /// Searches a `UILabel` with the given text in the view's subviews hierarchy.
    ///
    /// - Parameter text: The label text to search
    /// - Returns: A `UILabel` in the view's subview hierarchy, containing the searched text or `nil` if no `UILabel` was found.
    func findLabel(withText text: String) -> UILabel? 
        if let label = self as? UILabel, label.text == text 
            return label
        
        
        for subview in self.subviews 
            if let found = subview.findLabel(withText: text) 
                return found
            
        
        
        return nil
    

这是一个使用示例：

// Create a custom view for testing...
let customView = UIView()
customView.translatesAutoresizingMaskIntoConstraints = false
customView.backgroundColor = .red

// Set the custom view to a fixed height. In a real world application, you could use autolayouted content for height constraints
customView.addConstraint(NSLayoutConstraint(item: customView,
                                            attribute: .height,
                                            relatedBy: .equal,
                                            toItem: nil,
                                            attribute: .notAnAttribute,
                                            multiplier: 1,
                                            constant: 100))

// Create the alert and show it
let alert = UIAlertController(title: "Alert Title",
                                customView: customView,
                                fallbackMessage: "This should be a red rectangle",
                                preferredStyle: .actionSheet)

alert.addAction(UIAlertAction(title: "Yay!", style: .default, handler: nil))
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))

self.present(alert, animated: true, completion: nil)

这将显示如下内容：

【讨论】：

这很好用。只是想知道这是否会在审核过程中被拒绝，有什么想法吗？

没有涉及私有API，所以我不知道为什么Apple应该拒绝它。

只面临一个问题，customView 显示为灰色而不是红色。有什么想法吗？？

这看起来是一个不错的、干净的解决方案，但我认为人们强烈建议不要扩展 UIAlertController，因为 Apple 不希望你这样做，并且可能会在未来的更新中破坏你的“黑客”。这个解决方案可能仍然是这种情况吗？

我试图尽可能优雅地处理任何失败。如果 Apple 进行任何结构性更改，最坏的结果应该是警报不会显示自定义视图，而是仅显示后备文本消息，这正是针对这种情况的 API 的一部分。

【参考方案4】：

对于懒人来说，Swift 3.0 和 iOS >= 9 优化版 @Keller 的回答：

let alertController = UIAlertController(title: "\n\n\n\n\n\n", message: nil, preferredStyle: UIAlertControllerStyle.actionSheet)

let margin:CGFloat = 10.0
let rect = CGRect(x: margin, y: margin, width: alertController.view.bounds.size.width - margin * 4.0, height: 120)
let customView = UIView(frame: rect)

customView.backgroundColor = .green
alertController.view.addSubview(customView)

let somethingAction = UIAlertAction(title: "Something", style: .default, handler: (alert: UIAlertAction!) in print("something"))

let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: (alert: UIAlertAction!) in print("cancel"))

alertController.addAction(somethingAction)
alertController.addAction(cancelAction)

self.present(alertController, animated: true, completion:)

【参考方案5】：

我试图解决UIAlertController 的限制，但无论我如何管理，它都不够好。如果您仍在为此苦苦挣扎，我创建了a library，这可能会有所帮助。它使您可以使用一堆内置类型创建自定义工作表。它也可以扩展和重新设置样式。

【参考方案6】：

这是 @Cesare 解决方案的 Objective-C 版本

- (void) showPickerController 
    UIAlertController * alertController = [UIAlertController alertControllerWithTitle:@"Translation Language" message:nil preferredStyle:UIAlertControllerStyleActionSheet];
    UIView *customView = [[UIView alloc] init];
    [alertController.view addSubview:customView];
    customView.translatesAutoresizingMaskIntoConstraints = NO;
    [customView.topAnchor constraintEqualToAnchor:alertController.view.topAnchor constant:45].active = YES;
    [customView.rightAnchor constraintEqualToAnchor:alertController.view.rightAnchor constant:-10].active = YES;
    [customView.leftAnchor constraintEqualToAnchor:alertController.view.leftAnchor constant:10].active = YES;
    [customView.heightAnchor constraintEqualToConstant:250].active = YES;

    alertController.view.translatesAutoresizingMaskIntoConstraints = NO;
    [alertController.view.heightAnchor constraintEqualToConstant:430].active = YES;
    
    customView.backgroundColor = [UIColor greenColor];
    
    UIAlertAction* selectAction = [UIAlertAction actionWithTitle:@"Select" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) 
    ];
    UIAlertAction* cancelAction = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:^(UIAlertAction * action) 
    ];
    [alertController addAction:selectAction];
    [alertController addAction:cancelAction];
    
    [self presentViewController:alertController animated:YES completion:nil];