如何使用UIBarButtonSystemItem来更改UIBarButtonItem标识符？ （迅速）

Question

我想将代码从“播放”更改为“暂停”的UIBarButtonItem的标识符。我怎么能这样做？

由于

Answer 1

1）初始化一个按钮

//change to play
let button = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "someAction")
navigationBar.topItem.leftBarButtonItem = button

//change to pause
let button = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "someOtherAction")
navigationBar.topItem.leftBarButtonItem = button

2）只需更改文字：

navigationBar.topItem?.leftBarButtonItem?.title = "AnyText"

如果您在访问导航栏时遇到问题，最好只设置一些标签（我喜欢使用特定视图的负标签*来确保2个视图*没有获得相同的标签） 。 然后你可以这样做：

let navigationBar = (self.view.viewWithTag(-1) as UINavigationBar)
navigationBar.topItem?.leftBarButtonItem?.title = "AnyText"

Answer 2

我使用此代码切换编辑模式

@IBAction func editMode(sender: AnyObject) {
    self.setEditing(!self.editing, animated: true)
    let newButton = UIBarButtonItem(barButtonSystemItem: (self.editing) ? .Done : .Edit, target: self, action: #selector(editMode(_:)))
    self.navigationItem.setLeftBarButtonItem(newButton, animated: true)
}

Answer 3

对于工具栏项，以下是示例代码。

var player:AVAudioPlayer = AVAudioPlayer()

@IBOutlet var toolbar: UIToolbar!
@IBOutlet var playPauseButton: UIBarButtonItem!

@IBAction func playPause(sender: AnyObject) {

    if player.playing {

        player.pause()

        playPauseButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "playPause:")

        toolbar.items![0] = playPauseButton //apply for first toolbar item

    } else {

        player.play()

        playPauseButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "playPause:")

        toolbar.items![0] = playPauseButton //apply for first toolbar item


    }

}

Answer 4

此代码经过测试并与Swift 2一起使用

select user_userID, count(*) as orders_count from orders 
group by user_userID having orders_count > 1 

Answer 5

我看到了几个线程，这是实际做到我正在寻找的唯一答案。我唯一的问题是它将我的工具栏项移动到最左边，我把它放在中心位置。如果您的按钮以灵活的空格键为中心，或者它不是第一个按钮，只需更改索引，如下所示：     toolbar.items![1] = playPauseButton //apply for second toolbar item