让 AVAudioEngine 重复声音

我一直无法让下面的代码一遍又一遍地重复audioURL 处的声音。现在，它只在视图打开时播放一次，然后停止。

import UIKit
import AVFoundation
class aboutViewController: UIViewController {

    var audioUrl = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("chimes", ofType: "wav")!)
    var audioEngine = AVAudioEngine()
    var myPlayer = AVAudioPlayerNode()

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.

        audioEngine.attachNode(myPlayer)
        var audioFile = AVAudioFile(forReading: audioUrl, error: nil)
        var audioError: NSError?
        audioEngine.connect(myPlayer, to: audioEngine.mainMixerNode, format: audioFile.processingFormat)
        myPlayer.scheduleFile(audioFile, atTime: nil, completionHandler: nil)
        audioEngine.startAndReturnError(&audioError)
        myPlayer.play()


    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

Thanks!

经过几个小时的搜索，终于做到了：

class aboutViewController: UIViewController {
       
    var audioEngine: AVAudioEngine = AVAudioEngine()
    var audioFilePlayer: AVAudioPlayerNode = AVAudioPlayerNode()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        
        let filePath: String = NSBundle.mainBundle().pathForResource("chimes", ofType: "wav")!
        println("\(filePath)")
        let fileURL: NSURL = NSURL(fileURLWithPath: filePath)!
        let audioFile = AVAudioFile(forReading: fileURL, error: nil)
        let audioFormat = audioFile.processingFormat
        let audioFrameCount = UInt32(audioFile.length)
        let audioFileBuffer = AVAudioPCMBuffer(PCMFormat: audioFormat, frameCapacity: audioFrameCount)
        audioFile.readIntoBuffer(audioFileBuffer, error: nil)
        
        var mainMixer = audioEngine.mainMixerNode
        audioEngine.attachNode(audioFilePlayer)
        audioEngine.connect(audioFilePlayer, to:mainMixer, format: audioFileBuffer.format)
        audioEngine.startAndReturnError(nil)
        
        audioFilePlayer.play()
        audioFilePlayer.scheduleBuffer(audioFileBuffer, atTime: nil, options:.Loops, completionHandler: nil)
    }

    ...
}