swift - 如何修复 Xcode 错误 : Value of type 'AVAudioRecorder?' has no member 'URL'

Question

我是优达学城 iOS 开发人员的学生，正在开发用于录制和播放音频的应用程序 PitchPerfect。我正在使用 Xcode 10.2.1 以及模拟器和 Swift 4。我一直在密切关注类(class)说明，但我的 RecordSoundsViewController.swift 中的代码出现错误。我的构建一直失败。我收到以下错误:

“AVAudioRecorder?”类型的值？没有成员“URL”

我很乐意收到您关于如何推进并编译我的构建的建议。

我尝试更新我的 Xcode 版本(到我正在运行的当前版本 10.2.1)并切换到 Swift 4.2，但这似乎没有帮助。

//
//  RecordSoundsViewController.swift
//  PitchPerfect
//
//  Created by Shara Karasic on 6/1/19.
//  Copyright © 2019 Shara Karasic. All rights reserved.
//

import UIKit
import AVFoundation

class RecordSoundsViewController: UIViewController,       AVAudioRecorderDelegate {

    var audioRecorder: AVAudioRecorder!
    var recordedAudioURL:URL!

    @IBOutlet weak var recordingLabel: UILabel!
    @IBOutlet weak var recordButton: UIButton!
    @IBOutlet weak var stopRecordingButton: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        stopRecordingButton.isEnabled = false
        // Do any additional setup after loading the view, typically from a nib.
    }
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        print ("viewWillAppear called")
    }

    @IBAction func recordAudio(_ sender: AnyObject) {
        recordingLabel.text = "Recording in progress"
        stopRecordingButton.isEnabled = true
        recordButton.isEnabled = false

        let dirPath = NSSearchPathForDirectoriesInDomains(.documentDirectory,.userDomainMask, true)[0] as String
        let recordingName = "recordedVoice.wav"
        let pathArray = [dirPath, recordingName]
        let filePath = URL(string: pathArray.joined(separator: "/"))

        let session = AVAudioSession.sharedInstance()
        try! session.setCategory(AVAudioSessionCategoryPlayAndRecord, mode: AVAudioSessionModeDefault, options: AVAudioSession.CategoryOptions.defaultToSpeaker)

        try! audioRecorder = AVAudioRecorder(url: filePath!, settings: [:])
        audioRecorder.isMeteringEnabled = true
        audioRecorder.prepareToRecord()
        audioRecorder.record()
    }
    @IBAction func stopRecording(_ sender: Any) {
        recordButton.isEnabled = true
        stopRecordingButton.isEnabled = false
        recordingLabel.text = "Tap to Record"
        audioRecorder.stop()
        let audioSession = AVAudioSession.sharedInstance()
        try! audioSession.setActive(false)
    }
    func audioRecorderDidFinishRecording(_ recorder: AVAudioRecorder, successfully flag: Bool) {
        if flag {
            performSegue(withIdentifier: "stopRecording", sender: audioRecorder.URL)
        } else {
            print ("recording was not successful")
        }
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "stopRecording" {
            let playSoundsVC = segue.destination as! PlaySoundsViewController
            let recordedAudioURL  = audioRecorder.url
            playSoundsVC.recordedAudioURL = recordedAudioURL
        }
    }
}

我希望这段代码能够顺利运行，尤其是当我直接从 Udacity 类(class)中获得它时，但是我的构建失败了并且出现了错误:

“AVAudioRecorder?”类型的值？没有成员“URL”

Answer 1

您的代码似乎已过时，url 已小写，并使用传递的recorder 参数

performSegue(withIdentifier: "stopRecording", sender: recorder.url)

阅读 documentation 总是值得的

---

而且这四行根本行不通(URL(string is inappropriate)而且这是一种连接路径的可怕方式

let dirPath = NSSearchPathForDirectoriesInDomains(.documentDirectory,.userDomainMask, true)[0] as String
let recordingName = "recordedVoice.wav"
let pathArray = [dirPath, recordingName]
let filePath = URL(string: pathArray.joined(separator: "/"))

替换为

let dirURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
let fileURL = dirURL.appendingPathComponent("recordedVoice.wav")

...

try! audioRecorder = AVAudioRecorder(url: fileURL, settings: [:])

旁注:不鼓励尝试!，除非代码不会崩溃(比如在 FileManager 行中)