[英]UIBarButton not changing
@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")
}
我希望条形按钮更改为暂停符号,但是没有运气。 它同时打印“按下”和“此处”,但“测试”不起作用。 为什么图像没有变化?
您的方法是错误的。
在下一行中,
playStopButton = UIBarButtonItem(barButtonSystemItem: playStopArray[index], target: self, action: "startMusic:")
您实际上是在创建UIBarButtonItem
的新实例。 该按钮实际上并未添加到视图中。 而不是通过Interface Builder添加UIBarButtonItem
。 您可以以编程方式创建它。
阅读此问题以获取更多信息。 在UIBarButtonSystemItemPlay和UIBarButtonSystemItemPause之间切换
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.
}
这是我在Swift中的方法
func configureBars() {
isPlaying = false
// UIToolbar
let pickBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Search,
target: self,
action: "pickSong")
let playBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Play,
target: self,
action: "playPause")
let pauseBarButtonItem = UIBarButtonItem(barButtonSystemItem: .Pause,
target: self,
action: "playPause")
let leftFlexBBI = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace,
target: nil,
action: nil)
let rightFlexBBI = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace,
target: nil,
action: nil)
playItems = [pickBarButtonItem, leftFlexBBI, playBarButtonItem, rightFlexBBI]
pauseItems = [pickBarButtonItem, leftFlexBBI, pauseBarButtonItem, rightFlexBBI]
toolbar.items = playItems
}
请访问http://www.raywenderlich.com/36475/how-to-make-a-music-visualizer-in-ios ,也可以查看我的Github https://github.com/Charles-Hsu/MusicVisualizer
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