使用 AVAudioEngine 重復播放音頻文件

Question

我正在使用 iOS 應用程序 Swift 和 Xcode 6. 我想做的是使用 AVAudioEngine 播放音頻文件，直到此時一切正常。 但是我怎樣才能不停地播放它，我的意思是，當它結束播放時又會重新開始播放？

這是我的代碼：

/*==================== CONFIGURATES THE AVAUDIOENGINE ===========*/
    audioEngine.reset() //Resets any previous configuration on AudioEngine

    let audioPlayerNode = AVAudioPlayerNode() //The node that will play the actual sound
    audioEngine.attachNode(audioPlayerNode) //Attachs the node to the audioengine

    audioEngine.connect(audioPlayerNode, to: audioEngine.outputNode, format: nil) //Connects the applause playback node to the sound output
    audioPlayerNode.scheduleFile(applause.applauseFile, atTime: nil, completionHandler: nil)

    audioEngine.startAndReturnError(nil)
    audioPlayerNode.play() //Plays the sound

在說我應該為此使用 AVAudioPlayer 之前，我不能，因為稍后我將不得不使用一些效果並同時播放三個音頻文件，也重復播放。

Answer 1

我在另一個問題中找到了解決方案，並且也被@CarveDrone自動回答，所以我剛剛復制了他使用的代碼：

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)
    }

您唯一需要更改的是filePath常量。 這是原始答案的鏈接： 讓AVAudioEngine重復聲音

Answer 2

Swift 5 ，感謝@Guillermo Barreiro

    var audioEngine: AVAudioEngine = AVAudioEngine()
    var audioFilePlayer: AVAudioPlayerNode = AVAudioPlayerNode()

    override func viewDidLoad() {
        super. viewDidLoad()

        guard let filePath: String = Bundle.main.path(forResource: "chimes", ofType: "wav") else{ return }
        print("\(filePath)")
        let fileURL: URL = URL(fileURLWithPath: filePath)
        guard let audioFile = try? AVAudioFile(forReading: fileURL) else{ return }

        let audioFormat = audioFile.processingFormat
        let audioFrameCount = UInt32(audioFile.length)
        guard let audioFileBuffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: audioFrameCount)  else{ return }
        do{
            try audioFile.read(into: audioFileBuffer)
        } catch{
            print("over")
        }
        let mainMixer = audioEngine.mainMixerNode
        audioEngine.attach(audioFilePlayer)
        audioEngine.connect(audioFilePlayer, to:mainMixer, format: audioFileBuffer.format)
        try? audioEngine.start()
        audioFilePlayer.play()
        audioFilePlayer.scheduleBuffer(audioFileBuffer, at: nil, options:AVAudioPlayerNodeBufferOptions.loops)
    }