从 UITableViewCell 呈现 UIAlertController [英] Presenting UIAlertController from UITableViewCell

问题描述

我正在尝试向自定义 UITableViewCell 添加警报以显示 UIAlertView 我需要从 UIViewController 调用 presentViewController.但是，我不知道如何从 UITableViewCell 类访问当前的 UIViewController 实例.下面的代码是我尝试通过扩展来做到这一点.

I am trying to add alerts to a custom UITableViewCell to present an UIAlertView I need to call presentViewController from UIViewController. However, I am unaware of how to gain access to the current UIViewController instance from the UITableViewCell class. The below code is my attempt to do this with an extension.

我收到这个错误

表达式解析为未使用的函数.

Expression resolved to unused function.

extension UIViewController
{

    class func alertReminden(timeInterval: Int)
    {
        var refreshAlert = UIAlertController(title: "Refresh", message: "All data will be lost.", preferredStyle: UIAlertControllerStyle.Alert)

        refreshAlert.addAction(UIAlertAction(title: "Ok", style: .Default, handler: { (action: UIAlertAction!) in
            Alarm.createReminder("Catch the Bus",
                timeInterval: NSDate(timeIntervalSinceNow: Double(timeInterval * 60)))
        }))

        refreshAlert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: { (action: UIAlertAction!) in
            println("Handle Cancel Logic here")
        }))

        UIViewController.presentViewController(refreshAlert)


    }
}

class CustomRouteViewCell: UITableViewCell {

推荐答案

你可以使用这个扩展来查找呈现单元格的 viewController

You can use this extension to find the viewController that present the cell

extension UIView {
var parentViewController: UIViewController? {
    var parentResponder: UIResponder? = self
    while parentResponder != nil {
        parentResponder = parentResponder!.nextResponder()
        if parentResponder is UIViewController {
            return parentResponder as! UIViewController!
        }
    }
    return nil
}
}

或者使用rootViewController来展示:

UIApplication.sharedApplication().keyWindow?.rootViewController?.presentViewController(refreshAlert, animated: true, completion: nil)

Swift 4.2 更新

extension UIView {
    var parentViewController: UIViewController? {
        var parentResponder: UIResponder? = self
        while parentResponder != nil {
            parentResponder = parentResponder!.next
            if parentResponder is UIViewController {
                return parentResponder as? UIViewController
            }
        }
        return nil
    }
}

或者使用rootViewController来展示:

UIApplication.shared.keyWindow?.rootViewController?.present(alertVC, animated: true, completion: nil)

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