封闭 Catch 并非详尽无遗（录音）

Posted 2023-02-25

【中文标题】封闭 Catch 并非详尽无遗（录音）

【英文标题】：Enclosing Catch is not Exhaustive (Audio Recording)

【发布时间】：2016-08-03 14:47:15

【问题描述】：

我正在设置录音机，但在 soundRecorder = try AVAudioRecorder(URL: getFileURL(), settings: recordSettings as! [String : AnyObject]) 上出现错误，并出现以下错误 Errors thrown from here are not handled because the enclosing catch is not exhaustive

func setUpRecorder() 

    let recordSettings = [AVFormatIDKey : Int(kAudioFormatAppleLossless), AVEncoderAudioQualityKey : AVAudioQuality.Max.rawValue, AVEncoderBitRateKey : 320000, AVNumberOfChannelsKey : 2, AVSampleRateKey : 44100.0 ]

    var error: NSError?

    do 
        //  soundRecorder = try AVAudioRecorder(URL: getFileURL(), settings: recordSettings as [NSObject : AnyObject])
        soundRecorder =  try AVAudioRecorder(URL: getFileURL(), settings: recordSettings as! [String : AnyObject])
     catch let error1 as NSError 
        error = error1
        soundRecorder = nil
    

    if let err = error 
        print("AVAudioRecorder error: \(err.localizedDescription)")
     else 
        soundRecorder.delegate = self
        soundRecorder.prepareToRecord()
    

【参考方案1】：

错误信息具有误导性。一个

catch let error1 as NSError

是详尽的，因为所有错误都被桥接到NSError 自动地。

看来编译器被强制转换弄糊涂了

recordSettings as! [String : AnyObject]

这会导致错误的错误消息。解决方案是创建 首先设置正确类型的字典：

let recordSettings: [String: AnyObject] = [
    AVFormatIDKey : Int(kAudioFormatAppleLossless),
    AVEncoderAudioQualityKey : AVAudioQuality.Max.rawValue,
    AVEncoderBitRateKey : 320000,
    AVNumberOfChannelsKey : 2,
    AVSampleRateKey : 44100.0 ]

var error: NSError?
do 
    soundRecorder = try AVAudioRecorder(URL: getFileURL(), settings: recordSettings)
 catch let error1 as NSError  
    error = error1
    soundRecorder = nil

【参考方案2】：

您可以做几件事。

do 
    //  soundRecorder = try AVAudioRecorder(URL: getFileURL(), settings: recordSettings as [NSObject : AnyObject])
        soundRecorder =  try AVAudioRecorder(URL: getFileURL(), settings:     recordSettings as! [String : AnyObject])
     catch let error1 as NSError 
        error = error1
        soundRecorder = nil
     catch 
      //Exhaustive catch all.
    

或者你可以这样写

do 
    //  soundRecorder = try AVAudioRecorder(URL: getFileURL(), settings: recordSettings as [NSObject : AnyObject])
    soundRecorder =  try AVAudioRecorder(URL: getFileURL(), settings: recordSettings as! [String : AnyObject])
 catch 
  self.error = error as NSError
  soundRecorder = nil

这应该可行。