ios - 单击更改 BarButtonItem 图标

Question

我正在尝试创建一个计数器。这个想法很简单，你点击“播放”按钮，一旦你点击它就会消失并变成一个“暂停”图标，这将触发不同的 Action 。

我认为为计数器状态设置一个 var 并更改图标(只有一个按钮)就可以解决问题，但我不知道如何为“暂停”或出现在从 Storyboard面板创建下拉菜单时的下拉菜单。

这里是代码:

@IBOutlet weak var playButton: UIBarButtonItem!
var timer = NSTimer()
var currentStatus = "stopped"


@IBAction func playAction(sender: AnyObject) {
    if (currentStatus == "stopped"){
        timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("increaseTimer"), userInfo: nil, repeats: true)
        currentStatus = "running"
        // change button icon (playButton) to Stop
    }
    else {
        currentStatus = "stopped"
        timer.invalidate()
       // change button icon (playButton) to Play
    }

}

Answer 1

你可以这样设置按钮样式:

//setButton to play
yourBarButtonItem = UIBarButtonItem(UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "TheMethodThatTheButtonShouldCall"), animated: true)
//setButton to stop
yourBarButtonItem = UIBarButtonItem(UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Stop, target: self, action: "TheMethodThatTheButtonShouldCall"), animated: true)