在UIAlertViewDelegate中单击索引按钮未被调用

Question

在Objective之前，我们在UIAlertView中使用了委托:self，这样我们就能够调用方法，比如在index....but上按一下按钮，现在可以在哪里设置该委托？因为我的按钮点击索引方法没有被调用..。

import UIKit

class ViewController:UIViewController,UITableViewDelegate,UITableViewDataSource,UIAlertViewDelegate{

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell!{
let cell :UITableViewCell = UITableViewCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: nil)
cell.text = "HI \(indexPath.row)"
cell.detailTextLabel.text = "SWIFT"
return cell
}
func tableView(tableView: UITableView!, numberOfRowsInSection section: Int) -> Int
{
 return 5
}

 func tableView(tableView: UITableView!, didSelectRowAtIndexPath indexPath: NSIndexPath!)
 {


   var alert = UIAlertController(title: "Demo", message: "You have selected row number\(indexPath.row)", preferredStyle: UIAlertControllerStyle.Alert)
    alert.addAction(UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil))
    alert.addAction(UIAlertAction(title: "KILL", style: UIAlertActionStyle.Destructive, handler: nil))
    alert.addAction(UIAlertAction(title: "PUNE", style: UIAlertActionStyle.Default, handler: nil))
    alert.addAction(UIAlertAction(title: "Mumbai", style: UIAlertActionStyle.Default, handler: nil))
    alert.addAction(UIAlertAction(title: "Kolkata", style: UIAlertActionStyle.Default, handler: nil))
    alert.addAction(UIAlertAction(title: "Chennai", style: UIAlertActionStyle.Default, handler: nil))

    self.presentViewController(alert, animated: true, completion: nil)


 }
func demoFunction (myName:NSString)
{
    NSLog("%@", "swapnil")
}

func alertView(alertView: UIAlertView!, clickedButtonAtIndex buttonIndex: Int)
{
    NSLog("%@", "YOU PRESSED OK" )
    switch (buttonIndex)
        {
        case 0:NSLog("%@", "YOU PRESSED OK" )
        case 1:NSLog("%@", "YOU PRESSED KILLER" )
        case 2:NSLog("%@", "YOU PRESSED PUNE" )
        case 3:NSLog("%@", "YOU PRESSED MUMBAI" )
        case 4:NSLog("%@", "YOU PRESSED KOLKATA" )
        case 5:NSLog("%@", "YOU PRESSED Chennai" )
        default :NSLog("%@", "You have pressed default")

        }

}

}

Answer 1

UIAlertController不实现委托属性。它使用-addAction:的处理程序参数来处理按钮上的点击。下面是如何做到这一点的一个例子：

alert.addAction(UIAlertAction(title: "RandomTitle", style: UIAlertActionStyle.Default, handler:{(alert :UIAlertAction!) -> void in
    //Handle action here. 
    //You can also use the alert title property to differentiate between 
    //UIAlertActions and hand the same closure in to each one. E.i.

    if(action.title == "first option"){
        //handle when the user taps the "first option" button.
    }
}))

Answer 2

您不应该使用委托方法，实际上UIAlertController不提供委托。

就你而言，你的警报行动应该是这样的：

alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler:    {(alert :UIAlertAction!) in
        println("YOU PRESSED OK")

        }))

诸如此类的每一个动作！