使用Swift在工具栏中切换播放/暂停UIBarButtonItem

Question

我正在尝试在播放和暂停图像之间切换我的按钮,当我开始并使用Swift停止滚动条.我的代码:

import UIKit

class ViewController: UIViewController {

@IBOutlet var btnPlayPause: UIBarButtonItem!
var isPlaying = false
var timer = NSTimer()
var count = 0
@IBOutlet weak var lblTime: UILabel!
@IBOutlet var myToolbar: UIToolbar!




@IBAction func btnPlay(sender: UIBarButtonItem)
    {
   //set the button to animate

    self.myToolbar.setItems([self.btnPlayPause], animated: true)



    if !isPlaying //if the ticker is not ticking
    {
       //change the button to a pause button


        println("worked")//start the ticker

        timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("updateTime"), userInfo: nil, repeats: true)

        isPlaying = true

    }else{ //if the ticker is ticking

        //change the pause button to a play button

        self.btnPlayPause = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: nil)

        //pause the ticker
        timer.invalidate()
        //btnPlayPause.enabled = true
        isPlaying = false
         }

}

    @IBAction func btnReset(sender: UIBarButtonItem)
{
    //reset and restart the ticker
    timer.invalidate()
    count = 0
    timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("updateTime"), userInfo: nil, repeats: true)

}


@IBAction func btnStopit(sender: UIBarButtonItem)
{
    //stop and reset the ticker to "0"

    timer.invalidate()
    count = 0
    lblTime.text = String(count)

    isPlaying = false

}

func updateTime()
{
    //displays ticker label with count

    lblTime.text = String(count++)

}

override func viewDidLoad()
{

    super.viewDidLoad()
    let button = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "btnStopit:")
    self.btnPlayPause = button
}



override func didReceiveMemoryWarning()
{

    super.didReceiveMemoryWarning()

}


}

Play和工具栏上的所有其他按钮都清除,工具栏单独创建Pause按钮,如下所示:

我想只使用"暂停"按钮切换"播放"按钮,而不从工具栏中删除任何其他按钮.这可能吗？

如果有人能帮助我,我会非常感激!

谢谢

Answer 1

将按钮转换为UIBarButtonItem的新实例并不是必需的.首先为工具栏创建一个插座并检索现有项目,然后根据其在工具栏上的位置更改播放按钮项目.

在我的情况下,切换按钮位于左侧,因此我使用索引0访问它并将其替换为相应的切换.然后调用工具栏上的setItems()将更新工具栏.将动画设置为true以获得漂亮的小渐变动画.

@IBOutlet weak var toolBar: UIToolbar!

@IBAction func playPauseToggle(sender: UIBarButtonItem) {

    var toggleBtn = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Play, target: self, action: "playPauseToggle:")

    if playing {
        player.pause()
        playing = false
    } else {
        player.play()
        toggleBtn = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Pause, target: self, action: "playPauseToggle:")
        playing = true
    }

    var items = toolBar.items! 
    items[0] = toggleBtn
    toolBar.setItems(items, animated: true)

}