Question

该应用程序运行正常，但只要我点击chipmunkButton应用程序崩溃并提供以下错误：

错误：AVAudioPlayerNode.mm:678： - [AVAudioPlayerNode scheduleFile：atTime：completionHandler：]：必需条件为false： file！= nil 2015-05-10 17：24：25.269 Pitch Perfect [50278：1897012] *** 由于未捕获的异常而终止应用程序 'com.apple.coreaudio.avfaudio'，原因：'所需条件为假： file！= nil'

import UIKit
import AVFoundation

class PlaySoundsViewController: UIViewController {

    var audioRecording = AVAudioPlayer()
    var receivedAudio:RecordedAudio!
    var audioEngine:AVAudioEngine!
    var audioFile:AVAudioFile!



    func setupAudioPlayerWithFile(file:NSString, type:NSString) -> AVAudioPlayer  {


        //1
        var path = NSBundle.mainBundle().pathForResource(file as String, ofType: type as String)
        var url = NSURL.fileURLWithPath(path!)

        //2
        var error: NSError?

        //3
        var audioPlayer:AVAudioPlayer?
        audioPlayer = AVAudioPlayer(contentsOfURL: url, error: &error)

        //4
        return audioPlayer!
    }


    override func viewDidLoad() {
        super.viewDidLoad()


        audioRecording = AVAudioPlayer(contentsOfURL: receivedAudio.filePathUrl, error: nil)
        audioRecording.enableRate = true

        audioEngine = AVAudioEngine()

            }

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

    @IBAction func slowButton(sender: UIButton) {

        playButtons()
        audioRecording.rate = 0.5

    }


    @IBAction func fastSound(sender: UIButton) {
        audioRecording.rate = 2.0
        playButtons()
    }


    @IBAction func chipmunkButton(sender: UIButton) {

        playAudioWithVariablePitch(1000)

    }

    func playAudioWithVariablePitch(pitch: Float) {
        audioRecording.stop()
        audioEngine.stop()
        audioEngine.reset()

        var audioPlayerNode = AVAudioPlayerNode()
        audioEngine.attachNode(audioPlayerNode)

        var changePitchEffect = AVAudioUnitTimePitch()
        changePitchEffect.pitch = pitch
        audioEngine.attachNode(changePitchEffect)

        audioEngine.connect(audioPlayerNode, to: changePitchEffect, format: nil)
        audioEngine.connect(changePitchEffect, to: audioEngine.outputNode, format: nil)

        audioPlayerNode.scheduleFile(audioFile, atTime: nil, completionHandler: nil)
        audioEngine.startAndReturnError(nil)

        audioPlayerNode.play()


    }


    @IBAction func stopButton(sender: UIButton) {
       audioRecording.stop()

    }

    func playButtons() {
        audioRecording.stop()
        audioRecording.currentTime = 0
        audioRecording.play()

    }


}

Answer 1

非常小学。只需阅读错误信息！你在说：

var audioFile:AVAudioFile!

这意味着audioFile为零。好吧，之后你永远不会触摸audioFile，所以它从零开始并保持为零。因此，当你到达这一行时，你崩溃了：

audioPlayerNode.scheduleFile(audioFile, atTime: nil, completionHandler: nil)

...完全是因为audioFile是零。

Answer 2

如亚特提到的，audioFile是零

所以要解决这个问题，你必须进行设置。查看代码，您应该使用

    audioFile = AVAudioFile(forReading: receivedAudio.filePathUrl, error: nil)

这将设置audioFile，代码不会崩溃！

Swift：必需条件为false：file！= nil

2 个答案: