swift - 从 url 下载时如何播放音频？

Question

我需要创建音频播放器。我从 url 获取音频，然后从 url 下载音频然后播放。但是我需要在下载音频时播放音频，我该怎么做？

这是我的代码，如何从 url 播放:

 func URLSession(session: NSURLSession,
                downloadTask: NSURLSessionDownloadTask,
                didFinishDownloadingToURL location: NSURL){
    do {
        loadingView.hidden=true
        actInd.stopAnimating()
        UIApplication.sharedApplication().networkActivityIndicatorVisible = false
        player=try AVAudioPlayer(contentsOfURL: location)
        player?.delegate=self
        selectedAudio.status=true
        selectedAudio.isDownload=true
        player?.enableRate=true
        switch speedType_Index {
        case 0:
            appDelegate.player?.rate=Float(1)
            break
        case 1:
            appDelegate.player?.rate=Float(1.5)
            break
        case 2:
            appDelegate.player?.rate=Float(2)
            break
        case 3:
            appDelegate.player?.rate=Float(0.5)
            break
        default:
            break
        }
        switch playingType_Index {
        case 0:
            appDelegate.player?.numberOfLoops = 0
            break
        case 1:
            appDelegate.player?.numberOfLoops = -1
            break
        default:
            break
        }
        player?.volume=Float(volume)
        player?.play()
        self.tableView.reloadData()

    }catch let error as NSError{
        print(error.localizedDescription)
    }
}

func URLSession(session: NSURLSession,
                downloadTask: NSURLSessionDownloadTask,
                didWriteData bytesWritten: Int64,
                             totalBytesWritten: Int64,
                             totalBytesExpectedToWrite: Int64){
    let progress=Float(totalBytesWritten) / Float(totalBytesExpectedToWrite);
    bite.text=String(format: "%.1f%%",progress * 100)
}

Answer 1

AVAudioPlayer 无法直接从远程 URL 流式传输内容。

正如 documentation for AVAudioPlayer 中所说的那样

Apple recommends that you use this class for audio playback unless you are playing audio captured from a network stream or require very low I/O latency.

例如，另请参阅 this thread 或 this answer。

如果您想从远程 URL 进行流式传输，您可以使用 AVPlayer 而不是 AVAudioPlayer。可以找到文档 here

要创建一个能够流式传输的播放器，您需要按照这些思路做一些事情。

var player = AVPlayer() //declared as a property on your class

if let url = NSURL(string: "https://archive.org/download/testmp3testfile/mpthreetest.mp3") {
    player = AVPlayer(URL: url)
    player.volume = 1.0
    player.play()
}

希望对你有帮助。