UITableView 单元格调用 UIAlertController 弹出窗口...“present"错误 [英] UITableView cell invokes UIAlertController popup ..."present" error

问题描述

我有一个 tableview 定义，我试图在其中调用 UIAlertController 弹出窗口.我在原型 tableView 单元格中安装了一个按钮，当触摸该按钮时，IBAction 会处理该事件.问题是编译器不会让我.

I have a tableview definition in which I am attempting to invoke an UIAlertController popup. I installed a button in the prototype tableView cell, when the button is touched, an IBAction handles the event. The problem is that the compiler won't let me.

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

生成编译器错误:使用未解析的标识符‘存在’

Generates compiler error: "Use of unresolved identifier 'present'

代码如下:

class allListsCell: UITableViewCell {

    @IBOutlet var cellLable:       UIView!
    @IBOutlet var cellSelected:    UILabel!
    var colorIndex = Int()        

    @IBAction func cellMarkButton(_ sender: UIButton, forEvent event: UIEvent) {
        if  colors[self.colorIndex].selected == false {
            colors[self.colorIndex].selected = true
            cellSelected.text = "•"

            let alertController = UIAlertController(title: "???", message: "alertA", preferredStyle: .alert)

            let OKAction = UIAlertAction(title: "dismiss", style: .default) { (action:UIAlertAction!) in
                print("Sand: you have pressed the Dismiss button");
            }
            alertController.addAction(OKAction)

            present(alertController, animated: true, completion: nil) // ERROR

        } else {
            colors[self.colorIndex].selected = false
            cellSelected.text = ""
        }
    }

如果我评论那一行，应用程序会为每个单元格正确运行...

If I comment that one line, the app runs correctly for each cell...

推荐答案

无法从 TableViewCell 中调用present"方法，我建议在主控制器中有一个函数来显示您的 UIAlertController.

It is not possible to call the "present" method from a TableViewCell, I recommend having a function in the main controller to show your UIAlertController.

使用此代码，您可以实例化父驱动程序并执行任何可用函数:

Using this code you can instantiate the parent driver and execute any available function:

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

//UITableViewCell
if let controller = self.parentViewController as? YourController
{
    controller.showAlert()
}

以下是它与 CollectionViewCell 一起使用的示例:https://github.com/AngelH2/CollectionViewCell-Comunication/tree/master/CollectionCellAction

Here is an example of its use with a CollectionViewCell: https://github.com/AngelH2/CollectionViewCell-Comunication/tree/master/CollectionCellAction

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