iOS Delegate 未设置并返回 nil (Swift)

Question

当我尝试设置委托(delegate)时，结果为 nil，并且无法弄清楚为什么委托(delegate)未正确设置。

我有一个 View Controller ListViewController，我向其添加了一个 subview musicPlayer。 musicPlayer 是一个 UIView，它有一些按钮，点击时应该触发 ListViewController 中的操作。

musicPlayer 是这样设置的:

protocol MusicPlayerControlsDelegate {
    func playPauseClicked()
}


class musicPlayer: UIView {

var myDelegate: MusicPlayerControlsDelegate?

//this should trigger function in delegate
@IBAction func playOrPause(sender: AnyObject) {    
    println(myDelegate?)
    myDelegate?.playPauseClicked()        
}

ListViewController 是这样设置的:

class ListViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, MusicPlayerControlsDelegate {

var musicControls:musicPlayer = musicPlayer()

override func viewDidLoad() {
    musicControls.myDelegate = self
}

//adds musicPlayer nib as a subview to ListViewController
@IBAction func playInApp(sender: AnyObject) {

    let bundle = NSBundle(forClass: musicPlayer.self)
    var playerSubview = bundle.loadNibNamed("musicPlayerSubview", owner: nil, options: nil)[0] as UIView
    playerSubview.frame = CGRectMake(0, self.view.frame.width + 79, self.view.frame.width, 200)

    self.view.addSubview(playerSubview)
}

func playPauseClicked() {
    println("Your delegate is working")
}

当我运行它时，println(myDelegate) 是 nil 并且 println("Your delegate is working") 永远不会被调用。有关如何解决此问题的任何建议？

Answer 1

有时候，你忘记了segue

if(segue.identifier == "YourSegueIdentifier"){
        let v = segue.destinationViewController as! YourViewController

        v.delegate =  self

    }

这一行很重要，因为如果你忘记了它，它将无法工作

v.delegate = self