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像时,我正在尝试制作在iOS上的消息应用中显示的操作表.

我意识到在新的UIAlertController中,我们无法适应任何自定义视图.我有什么方法可以做到这一点？

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)

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.

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:{})
    }

迅速

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的

  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.如果某些东西不起作用(由于UIAlertController布局中的未来更改),甚至还有一个回退消息字符串.

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
    }
}

这是一个用法示例:

// 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)

这会显示如下: