播放声音有一点延迟

我的应用程序中有一个声音，当出现视图时会自动启动；但是，正如标题所说，我希望声音开始时有一点延迟，大约在视图出现后半秒。我尝试使用 PlayAtTime，但是它不起作用或者我设置了错误...... 这是我的代码：

var player = AVAudioPlayer?
override func viewDidLoad()
{
    super.viewDidLoad()
    playAudioWithDelay()
}

func playAudioWithDelay()
{
    let file = NSBundle.mainBundle().URLForResource("PR1", withExtension: "wav")
    player = AVAudioPlayer(contentsOfURL: file, error: nil)
    player!.volume = 0.5
    player!.numberOfLoops = -1
    player!.playAtTime(//I tried with 0.5 but doesn't work)
    player!.prepareToPlay()
    player!.play()
}

你可以尝试使用这个：

let seconds = 1.0//Time To Delay
let delay = seconds * Double(NSEC_PER_SEC)  // nanoseconds per seconds
var dispatchTime = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))

dispatch_after(dispatchTime, dispatch_get_main_queue(), {
    //Play Sound here
})

完整代码：

func playAudioWithDelay()
{
    let file = NSBundle.mainBundle().URLForResource("PR1", withExtension: "wav")
    player = AVAudioPlayer(contentsOfURL: file, error: nil)
    player!.volume = 0.5
    player!.numberOfLoops = -1
    player!.playAtTime(//I tried with 0.5 but doesn't work)
    player!.prepareToPlay()
    let seconds = 1.0//Time To Delay
    let delay = seconds * Double(NSEC_PER_SEC)  // nanoseconds per seconds
    var dispatchTime = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))

    dispatch_after(dispatchTime, dispatch_get_main_queue(), {
        player!.play()
    })
}