@IBOutlet weak var playStopButton: UIBarButtonItem!
var playStopArray = [UIBarButtonSystemItem.Pause, UIBarButtonSystemItem.Play]
var index = 0
@IBOutlet weak var image: UIImageView!
@IBAction func playButton(sender: UIBarButtonItem) {
println("pressed")
playStopButton = UIBarButtonItem(barButtonSystemItem: playStopArray[index], target: self, action: "startMusic:")
println("here")
if index == 0 {
index = 1
}
else {
index = 0
}
}
func startMusic() {
println("test")
}
我预计条形按钮会更改为暂停符号,但没有成功。它打印“pressed”和“here”,但“test”不起作用。为什么图像没有变化?
你的做法是错误的。
在下面的行中,
playStopButton = UIBarButtonItem(barButtonSystemItem: playStopArray[index], target: self, action: "startMusic:")
您实际上正在创建一个新实例UIBarButtonItem
。该按钮实际上并未添加到视图中。而不是添加UIBarButtonItem
通过界面生成器。您可以通过编程方式创建它。
阅读此问题以获取更多信息。在 UIBarButtonSystemItemPlay 和 UIBarButtonSystemItemPause 之间切换 https://stackoverflow.com/questions/9068629/toggle-between-uibarbuttonsystemitemplay-and-uibarbuttonsystemitempause
var playButton:UIBarButtonItem!
var pauseButton:UIBarButtonItem!
func setup()
{
playButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "startMusic:")
pauseButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "stopMusic:")
}
func startMusic:(button : UIBarButtonItem)
{
self.navigationItem.rightBarButtonItem = pauseButton // Switch to pause.
//Other code.
}
func stopMusic:(button : UIBarButtonItem)
{
self.navigationItem.rightBarButtonItem = playButton// Switch to play.
//Other code.
}
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