Swift 自定义 UIAlertView

Posted 2023-02-23

【中文标题】Swift 自定义 UIAlertView

【英文标题】：Swift Custom UIAlertView

【发布时间】：2016-05-26 19:58:04

【问题描述】：

我正在尝试制作确认删除弹出视图。因为我想要的设计与典型的UIAlertView 弹出窗口的样式有很大不同，所以我决定创建一个自定义的ConfirmationViewController 来触发弹出窗口。

这是典型的UIAlertView 的样子：

这就是我想要的样子：

这是我目前制作自定义 ConfirmationViewController 弹出窗口的方式：

let confirmationViewController = ConfirmationViewController()
confirmationViewController.delegate = self
confirmationViewController.setTitleLabel("Are you sure you want to remove \(firstName)?")
confirmationViewController.modalPresentationStyle = UIModalPresentationStyle.Popover
confirmationViewController.preferredContentSize = CGSizeMake(230, 130)

let popoverConfirmationViewController = confirmationViewController.popoverPresentationController
popoverConfirmationViewController?.permittedArrowDirections = UIPopoverArrowDirection(rawValue: 0)
popoverConfirmationViewController?.delegate = self
popoverConfirmationViewController?.sourceView = self.view
popoverConfirmationViewController?.sourceRect = CGRectMake(CGRectGetMidX(self.view.bounds), CGRectGetMidY(self.view.bounds),0,0)
presentViewController(
    confirmationViewController,
    animated: true,
    completion: nil)

当按下CANCEL 或REMOVE 按钮时，我收到通知的方式如下：

extension UserProfileTableViewController: ConfirmationViewControllerDelegate 
    func cancelButtonPressed() 
        print("Cancel button pressed")
    

    func confirmationButtonPressed(objectToDelete: AnyObject?) 
        print("Delete button pressed")
    

但是，我喜欢使用 UIAlertView 的原因是我可以在按下特定按钮时硬编码想要执行的操作，如下所示：

let alertController = UIAlertController(title: nil, message: nil, preferredStyle: .Alert)

let cancelAction = UIAlertAction(title: "Cancel", style: .Default, handler: (ACTION) in
    print("Perform cancel action")
)

let deleteAction = UIAlertAction(title: "Remove", style: .Destructive, handler: (ACTION) in
    print("Perform delete action")
)

alertController.addAction(cancelAction)
alertController.addAction(deleteAction)

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

所以我的问题是，我如何创建一个完成处理程序（内联），以便当使用我的自定义 ConfirmationViewController 按下 CANCEL 或 REMOVE 按钮时，我可以触发操作，就像我'已经展示了它是如何使用UIAlertController 完成的，而不是我目前使用委托的方式？

仅使用UIAlertController 创建我正在寻找的自定义弹出窗口的答案吗？如果是这样，我怎样才能将它定制到我正在寻找的程度？

在此先感谢，很抱歉发了这么长的帖子 :)

附：这是我的ConfirmationViewController 和ConfirmationViewControllerDelegate 的样子：

protocol ConfirmationViewControllerDelegate 
    func cancelButtonPressed()
    func confirmationButtonPressed(objectToDelete: AnyObject?)


class ConfirmationViewController: UIViewController 
    var didSetupConstraints = false

    let titleLabel = UILabel.newAutoLayoutView()
    let buttonContainer = UIView.newAutoLayoutView()
    let cancelButton = ButtonWithPressingEffect.newAutoLayoutView()
    let confirmationButton = ButtonWithPressingEffect.newAutoLayoutView()

    var delegate: ConfirmationViewControllerDelegate?

    var objectToDelete: AnyObject?

    override func viewDidLoad() 
        super.viewDidLoad()

        view.backgroundColor = UIColor.whiteColor()

        titleLabel.numberOfLines = 0

        cancelButton.backgroundColor = UIColor.colorFromCode(0x7f7f7f)
        cancelButton.layer.cornerRadius = 5
        cancelButton.setAttributedTitle(NSMutableAttributedString(
            string: "CANCEL",
            attributes: [
                NSFontAttributeName: UIFont(name: "AvenirNextLTPro-Demi", size: 12)!,
                NSForegroundColorAttributeName: UIColor.whiteColor(),
                NSKernAttributeName: 0.2
            ]
        ), forState: UIControlState.Normal)
        cancelButton.addTarget(self, action: #selector(cancelButtonPressed), forControlEvents: .TouchUpInside)

        confirmationButton.backgroundColor = Application.redColor
        confirmationButton.layer.cornerRadius = 5
        confirmationButton.setAttributedTitle(NSMutableAttributedString(
            string: "REMOVE",
            attributes: [
                NSFontAttributeName: UIFont(name: "AvenirNextLTPro-Demi", size: 12)!,
                NSForegroundColorAttributeName: UIColor.whiteColor(),
                NSKernAttributeName: 0.2
            ]
        ), forState: UIControlState.Normal)
        confirmationButton.addTarget(self, action: #selector(confirmationButtonPresssed), forControlEvents: .TouchUpInside)

        view.addSubview(titleLabel)
        view.addSubview(buttonContainer)
        buttonContainer.addSubview(cancelButton)
        buttonContainer.addSubview(confirmationButton)
        updateViewConstraints()
    

    func cancelButtonPressed() 
        delegate?.cancelButtonPressed()
        dismissViewControllerAnimated(false, completion: nil)
    

    func confirmationButtonPresssed() 
        delegate?.confirmationButtonPressed(objectToDelete)
        dismissViewControllerAnimated(false, completion: nil)
    

    func setTitleLabel(text: String) 
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.alignment = NSTextAlignment.Center
        paragraphStyle.lineSpacing = 4.5
        titleLabel.attributedText = NSMutableAttributedString(
            string: text,
            attributes: [
                NSFontAttributeName: UIFont(name: "AvenirNextLTPro-Regular", size: 14)!,
                NSForegroundColorAttributeName: UIColor.colorFromCode(0x151515),
                NSKernAttributeName: 0.5,
                NSParagraphStyleAttributeName: paragraphStyle
            ]
        )
    

    override func updateViewConstraints() 
        if !didSetupConstraints 
            titleLabel.autoPinEdgesToSuperviewEdgesWithInsets(UIEdgeInsets(top: 10, left: 10, bottom: 0, right: 10), excludingEdge: .Bottom)
            titleLabel.autoAlignAxisToSuperviewAxis(.Vertical)

            buttonContainer.autoPinEdge(.Top, toEdge: .Bottom, ofView: titleLabel, withOffset: 3)
            buttonContainer.autoAlignAxisToSuperviewAxis(.Vertical)
            buttonContainer.autoPinEdgeToSuperviewEdge(.Bottom, withInset: 10)

            let contactViews: NSArray = [cancelButton, confirmationButton]
            contactViews.autoDistributeViewsAlongAxis(.Horizontal, alignedTo: .Horizontal, withFixedSpacing: 7, insetSpacing: true, matchedSizes: false)

            cancelButton.autoPinEdgeToSuperviewEdge(.Top)
            cancelButton.autoPinEdgeToSuperviewEdge(.Bottom)
            cancelButton.autoSetDimensionsToSize(CGSize(width: 100, height: 50))

            confirmationButton.autoPinEdgeToSuperviewEdge(.Top)
            confirmationButton.autoPinEdgeToSuperviewEdge(.Bottom)
            confirmationButton.autoSetDimensionsToSize(CGSize(width: 100, height: 50))

            didSetupConstraints = true
        

        super.updateViewConstraints()
    

【问题讨论】：

ConfirmationViewController 类是否在您的控制之下并且可以编辑？

是的先生，我刚刚更新为包含 ConfirmationViewController @SeanCAtkinson 的代码

【参考方案1】：

类似下面的东西应该允许它。请注意，可以进行很多改进。例如，您可以对要删除的对象使用泛型而不是 AnyObject。如果你通过内联闭包，你也不一定需要传递它，所以你可能只是删除它。

你也可以让你的按钮更可重用，而不是硬编码来取消和删除，但现在我们要离开主题了 :)

class ConfirmViewController : UIViewController 
    var onCancel : (() -> Void)?
    var onConfirm : ((AnyObject?) -> Void)?

    var objectToDelete : AnyObject?

    func cancelButtonPressed() 
        // defered to ensure it is performed no matter what code path is taken
        defer 
            dismissViewControllerAnimated(false, completion: nil)
        

        let onCancel = self.onCancel
        // deliberately set to nil just in case there is a self reference
        self.onCancel = nil
        guard let block = onCancel else  return 
        block()
    

    func confirmationButtonPresssed() 
        // defered to ensure it is performed no matter what code path is taken
        defer 
            dismissViewControllerAnimated(false, completion: nil)
        
        let onConfirm = self.onConfirm
        // deliberately set to nil just in case there is a self reference
        self.onConfirm = nil
        guard let block = onConfirm else  return 
        block(self.objectToDelete)
    


let confirm = ConfirmViewController()
confirm.objectToDelete = NSObject()
confirm.onCancel = 
    // perform some action here

confirm.onConfirm =  objectToDelete in
    // delete your object here

【讨论】：

我非常喜欢这种设计模式。是否有特殊原因会使用委托而不是这种模式来获取视图？ @SeanCATkinson

真的取决于用例。在这种情况下，基于块的 API 可以很好地工作，因为它很简单，并且您可以在创建实例时声明行为。随着您的需求变得越来越复杂，您将倾向于委托代理。

快速问题.. 如果我想让 onConfirm 函数引用将在 ConfirmationViewController 中修改的变量怎么办？我在 onConfirm 函数中使用的任何对象都将设置为我传入时对象的值，而不是代码实际运行时的值，对吗？

我需要在这种情况下使用委托，对吗？ @SeanCATkinson

它将通过引用保存 ConfirmationViewController 中的变量，而不是值本身。这意味着如果在 onComfirm 块运行时该值已更改，它将使用新值而不是旧值。如果您需要它来使用旧值，请在声明 onConfirm 块之外的局部变量中捕获您想要的特定值，并改为引用该新变量。