UIAlertController - 向操作表添加自定义视图

Question

当我们尝试在屏幕截图中附加图片时，我正在尝试制作iOS上的消息应用中显示的动作表。

我意识到在新的UIAlertController中，我们无法适应任何自定义视图。我能用这种方式做到这一点吗？

我的代码看起来很标准。

MsgBox "Please select APPS Invoice file"
APPSInvoiceFN = Application.GetOpenFilename'

If APPSInvoiceFN = False Then ' User Pressed Cancel
    MsgBox "APPS Invoice file not selected. APPS invoice will not be updated."
    Application.ScreenUpdating = True
    Exit Sub
Else
    On Error GoTo ErrHandler
    Set APPSInvoiceWB = Workbooks.Open(APPSInvoiceFN)
    On Error GoTo 0

APPSInvoiceWB.SaveAs FileFormat:=51
APPSInvoiceWB.Close savechanges:=True
APPSInvoiceWB = Workbooks.Open(APPSInvoiceFN & "x")

Answer 1

UIAlertController扩展了UIViewController，它有一个view属性。您可以根据自己的心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，但是下次Apple调整UIAlertController的设计时，这很容易就会破坏。

Swift 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:{})
    }

<强>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:{})

<强>目标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:^{}];

话虽这么说，一个不那么hacky的方法是使你自己的视图子类与UIAlertController的UIAlertActionStyle布局类似。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

Answer 2

到目前为止，我发现使用AutoLayout约束的最干净的解决方案：

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：

Answer 3

我为UIAlertController编写了一个扩展（在Swift 4中），它解决了autolayout的布局问题。甚至还有一个回退消息字符串，以防万一不起作用（由于UIAlertController布局的未来变化）。

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: UIAlertControllerStyle) {

        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)

将显示如下内容：

Answer 4

对于懒惰的人来说，Swift 3.0和iOS＆gt; =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:{})

Answer 5

我试图解决UIAlertController限制，但无论我如何管理，它都不够好。如果您仍然在努力解决这个问题，我创建了a library可能会有所帮助。它允许您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计。

Answer 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];
}