带AVAudioEngine的循环音频

Question

我一直在obj-c中工作，但我想让自己头脑清醒。我的代码快到了，但我只是不知道如何循环我的wav。它在播放一次之后就停止了。我已经找到了一些指令，但我还没有为我的代码找到解决方案。我希望有人知道答案，并能帮助我。所以问题是:当按下@IBAction func playButtonTapped时，我必须做些什么来使wav循环?？我会给出所有的代码，只是为了确定。谢谢：-)

class ViewController: UIViewController {

    @IBOutlet var startAllButton: UIButton!
    var audioEngine = AVAudioEngine()
    var playerNode = AVAudioPlayerNode()



    let timeShift = AVAudioUnitTimePitch()
    let pedoMeter = CMPedometer()
    let bpm: Float = 110


    var avgStarted: Bool = false

    var steps: Int = 0
    var timer = Timer()
    var adjustedBpm: Float = 110

    var timerCount = 10 {
        didSet {
            if timerCount == 0 {
                stopCountingSteps()


            }
        }
    }

    var lastTap: Date? = nil

    @IBOutlet weak var tempoTap: UIButton!
    @IBOutlet weak var slider: UISlider!
    @IBOutlet weak var label: UILabel!
    @IBOutlet weak var playButton: UIButton!
    @IBOutlet weak var timerLabel: UILabel!
    @IBOutlet weak var stepCountLabel: UILabel!
    @IBOutlet weak var avgLabel: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        setup()
    }

    func setup() {
        label.text = "110"
        audioEngine.attach(playerNode)
        audioEngine.attach(timeShift)
        audioEngine.connect(playerNode, to: timeShift, format: nil)
        audioEngine.connect(timeShift, to: audioEngine.mainMixerNode, format: nil)
        audioEngine.prepare()
        timerLabel.text = ""
        stepCountLabel.text = ""
        do {
            try audioEngine.start()
        } catch {
            print("Could not start audio engine")
        }
    }


    @IBAction func sliderValueChanged(_ sender: UISlider) {
        label.text = String(sender.value)



        self.label.text = String(format:"%.f", sender.value)

        adjustedBpm = sender.value
        timeShift.rate = adjustedBpm/bpm

    }

    @IBAction func playButtonTapped(_ sender: Any) {


        let url = Bundle.main.url(forResource: "25loop110", withExtension: ".wav")
              if let url = url {
                  do {
                      let audioFile = try AVAudioFile(forReading: url)


                    timeShift.rate = adjustedBpm/bpm
                      playerNode.scheduleFile(audioFile, at: nil, completionHandler: nil)

                  } catch {
                      print("could not load audio file")
                  }
              } else {
                  print("could not load audio file")
              }
              playerNode.play()

    }

Answer 1

问题是这几条线：

let audioFile = try AVAudioFile(forReading: url)
playerNode.scheduleFile(audioFile, at: nil, completionHandler: nil)

环路在哪里？无处可去。这段代码只播放一次文件。

不能用AVAudioEngine中的文件循环。你用缓冲区循环。将文件读入缓冲区并调用scheduleBuffer(buffer, at: nil, options: .loops)。