DispatchSource.makeTimerSource當按下後退按鈕時崩潰應用程序Swift

Question

我已經實現了使用DispatchSource和計時器工作的錄製音頻（錄製和播放工作正常）的計時器，但是當我按下我的導航控制器選項卡上的後退按鈕時，應用程序崩潰。我可以毫無問題地前進到下一個屏幕。 錯誤：線程1：EXC_BAD_INSTRUCTION（code = EXC_I386_INVOP，subcode = 0x0）

有人請給我一個暗示，爲什麼這是？

我的看法控制器代碼：

import Foundation 
import UIKit 
import AVFoundation 

class RecordGreetingController: UIViewController { 

@IBOutlet weak var timeLabel: UILabel! 
var audioPlayer: AVAudioPlayer! 
var updateTimer = DispatchSource.makeTimerSource(flags: [], queue: DispatchQueue.main) 

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

@IBAction func toggleRecordButton(_ sender: UIButton) { 
    if AudioRecorderManager.shared.recorder == nil { 
     if AudioRecorderManager.shared.recordAudio(fileName: "NewRecording") { 
      updateTimer.resume() 
     } 

     let formatter = DateComponentsFormatter() 
     formatter.zeroFormattingBehavior = .pad 
     formatter.includesApproximationPhrase = false 
     formatter.allowedUnits = [.minute, .second] 
     formatter.calendar = Calendar.current 

     updateTimer.schedule(deadline: DispatchTime.now(), repeating: DispatchTimeInterval.milliseconds(100)) 

     updateTimer.setEventHandler { [weak self] in 
      self?.timeLabel.text = formatter.string(from: AudioRecorderManager.shared.recorder!.currentTime) 
     } 
    } 
    else { 
     AudioRecorderManager.shared.finishRecording() 
     AudioRecorderManager.shared.recorder = nil 
     updateTimer.suspend() 
    } 
} 

}

我AudioRecorderManager類：

import Foundation 
import AVFoundation 

class AudioRecorderManager: NSObject, AVAudioRecorderDelegate { 


static let shared = AudioRecorderManager() 

var recordingSession: AVAudioSession! 
var recorder: AVAudioRecorder? 


func setup() { 

    recordingSession = AVAudioSession.sharedInstance() 

    do { 
     try recordingSession.setCategory(AVAudioSessionCategoryPlayAndRecord, with: .defaultToSpeaker) 
     try recordingSession.setActive(true) 

     // Request permission from user 
     recordingSession.requestRecordPermission{ (allowed) in 
      if allowed { 
       print("Mic authorised") 
      } 
      else { 
       print("Mic not authorised") 
       // TODO display alert to allow microphone access in settings to operate 
      } 
     } 
    } 
    catch { 
     print("Failed to set category", error.localizedDescription) 
    } 
} 

var meterTimer: Timer? 
var recorderApc0: Float? = 0 
var recorderPeak0: Float? = 0 

// Starts the recording session 
func recordAudio(fileName:String) -> Bool { 
    let url = getUserPath().appendingPathComponent(fileName+".m4a") 
    let audioURL = URL.init(fileURLWithPath: url.path) 
    let recordSettings: [String: Any] = [ 
     AVFormatIDKey: NSNumber(value: kAudioFormatAppleLossless), 
     AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue, 
     AVEncoderBitRateKey: 12000.0, 
     AVNumberOfChannelsKey: 1, 
     AVSampleRateKey: 44100.0 
    ] 

    do { 
     recorder = try AVAudioRecorder(url: audioURL, settings: recordSettings) 
     recorder?.delegate = self 
     recorder?.isMeteringEnabled = true 
     recorder?.prepareToRecord() 
     recorder?.record() 

     self.meterTimer = Timer.scheduledTimer(withTimeInterval: 0.1, repeats: true, block: { (timer: Timer) in 
      // Update recorder meter values 
      if let recorder = self.recorder { 
       recorder.updateMeters() 
       self.recorderApc0 = recorder.averagePower(forChannel: 0) 
       self.recorderPeak0 = recorder.peakPower(forChannel: 0) 
      } 
     }) 
     print("Recording") 
     return true 
    } 
    catch { 
     print("Error recording") 
     return false 
    } 
} 

// Stop recording 
func finishRecording() { 
    self.recorder?.stop() 
    self.meterTimer?.invalidate() 
} 

// Gets path for the folder the file is being saved to 
func getUserPath() -> URL { 
    return FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0] 
} 

func audioRecorderDidFinishRecording(_ recorder: AVAudioRecorder, successfully flag: Bool) { 
    print("Audio Manager did finish recording", flag) 
} 

func audioRecorderEncodeErrorDidOccur(_ recorder: AVAudioRecorder, error: Error?) { 
    print("Error encoding ", error?.localizedDescription ?? "") 
} 

}

Answer 1

這最終被解決我的問題。忽略來自上述兩個誰沒有解決這個問題的一個心懷不滿的向下投票：

var updateTimer: DispatchSourceTimer? 
@IBOutlet weak var timeLabel: UILabel! 

func startTimer() { 
    let formatter = DateComponentsFormatter() 
    formatter.zeroFormattingBehavior = .pad 
    formatter.includesApproximationPhrase = false 
    formatter.allowedUnits = [.minute, .second] 
    formatter.calendar = Calendar.current 
    let queue = DispatchQueue.main 
    updateTimer = DispatchSource.makeTimerSource(queue: queue) 
    updateTimer!.schedule(deadline: .now(), repeating: .milliseconds(100)) 
    updateTimer!.setEventHandler { [weak self] in 
     self?.timeLabel.text = formatter.string(from: AudioRecorderManager.shared.recorder!.currentTime) 
    } 
    updateTimer!.resume() 
} 

func stopTimer() { 
    updateTimer?.cancel() 
    updateTimer = nil 
} 

deinit { 
    self.stopTimer() 
} 

@IBAction func toggleRecordButton(_ sender: UIButton) { 
    if AudioRecorderManager.shared.recorder == nil { 
     if AudioRecorderManager.shared.recordAudio(fileName: "NewRecording") { 
       startTimer() 
     } 
    } 
    else { 
     stopTimer() 
     AudioRecorderManager.shared.finishRecording() 
     AudioRecorderManager.shared.recorder = nil 
    } 
}