在读AVAudioFile缓冲区上崩溃会快速创建波形

Question

我一直在AVAudioPlayer工作，并掀起了波澜。我正在使用AudioArmada Github在AudioArmada Pods的帮助下绘制波浪。但在某些情况下，AVAudioFile会在读取缓冲时间时崩溃。

代码如下：

public func openFile(_ file: URL) {
    let audioFile = try! AVAudioFile(forReading: file)
    // specify the format we WANT for the buffer
    let format = AVAudioFormat(commonFormat: .pcmFormatFloat32, sampleRate: audioFile.fileFormat.sampleRate, channels: audioFile.fileFormat.channelCount, interleaved: false)
    // initialize and fill the buffer
    let buffer = AVAudioPCMBuffer(pcmFormat: format!, frameCapacity: UInt32(audioFile.length))
    try! audioFile.read(into: buffer!)
    // copy buffer to readFile struct
    readFile.floatValuesLeft = Array(UnsafeBufferPointer(start: buffer?.floatChannelData?[0], count:Int(buffer!.frameLength)))
    readFile.populated = true
    reload(zoomFactor: zoomFactor)
}

public func reload(zoomFactor: Float = 1.0) {
    self.zoomFactor = zoomFactor
    setNeedsDisplay()
}

func drawSoundcloudWaveform(_ rect: CGRect) {
  let path = UIBezierPath()
  path.move(to: CGPoint(x: 0.0, y: rect.height/2))
  var index = 0
  while index < readFile.leftPoints.count {
  let point = readFile.leftPoints[index]
  let drawFrom = CGPoint(x: point.x, y: path.currentPoint.y)
  path.move(to: drawFrom)
  let drawPointBottom = CGPoint(x: point.x, y: path.currentPoint.y + (point.y))
   path.addLine(to: drawPointBottom)
   path.addLine(to: CGPoint(x: drawPointBottom.x + pixelWidth, y: drawPointBottom.y))
   path.addLine(to: CGPoint(x: drawFrom.x + pixelWidth, y: drawFrom.y))
   path.close()
   path.move(to: drawFrom)
   let drawPointTop = CGPoint(x: point.x, y: path.currentPoint.y - (point.y))
   path.addLine(to: drawPointTop)
   path.addLine(to: CGPoint(x: drawPointTop.x + pixelWidth, y: drawPointTop.y))
   path.addLine(to: CGPoint(x: drawFrom.x + pixelWidth, y: drawFrom.y))
   path.close()
   index = index + Int(pixelWidth) + Int(pixelSpacing)
   }
    UIColor(red:0.21, green:0.77, blue:0.78, alpha:1.0).set()
    path.stroke()
    path.fill()
}

以下病例：

1. 运行案例： 保护让文件= Bundle.main.url(forResource："Beat9"，withExtension：".mp3")或{返回}openFile(文件) AVAudioPCMBuffer输出: AVAudioPCMBuffer@0x6000005c9300: 0/35864064字节

波屏截图：

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1. 坠机案： Bundle.main.url(forResource："IshqMubarak"，withExtension：".mp3") withExtension{返回}openFile(文件) AVAudioPCMBuffer输出: AVAudioPCMBuffer@0x600003eb1180: 0/0字节/i，为什么要显示零字节缓冲区？

错误：致命错误：“尝试！”表达式意外引发一个错误: Foundation._GenericObjCError.nilError: file Foundation._GenericObjCError.nilError第63行

问题：如何解决这个问题，为什么有时会崩溃？

任何帮助都将不胜感激。

提前谢谢。

Answer 1

看到这个错误，它会在WaveformZoomable.swift of AudioArmada的第63行崩溃，在该行中，try!被用于零对象。

AVAudioFile抛出(第56行相同)：

func read(into buffer: AVAudioPCMBuffer) throws

您可以使用

• try?暂时摆脱崩溃
• 或者try catch找出它无法阅读的原因
• 并在AudioArmada上提交一个问题