如何将AVAudioRecorder声明为全局变量

Question

我正在努力理解为什么我不能将这里看到的记录器变量声明为可用于该类中的任何操作。

编辑以完整显示一个新的测试项目，但仍显示相同的行为。 我只是似乎无法全局声明记录器var。 看评论 ：

import Cocoa
import AVFoundation

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate, AVAudioRecorderDelegate {

    var recorder : AVAudioRecorder = AVAudioRecorder() // remove this and clean up un-declared recorder vars, and it appears to record as expected

    @IBOutlet weak var window: NSWindow!


    func applicationDidFinishLaunching(aNotification: NSNotification) {
        // Insert code here to initialize your application
    }

    func applicationWillTerminate(aNotification: NSNotification) {
        // Insert code here to tear down your application
    }


    @IBAction func startRecording(sender: AnyObject) {
        var recordSettings = [
            AVFormatIDKey: kAudioFormatAppleLossless,
            AVEncoderAudioQualityKey : AVAudioQuality.Medium.rawValue,
            AVEncoderBitRateKey : 16,
            AVNumberOfChannelsKey: 2,
            AVSampleRateKey : 44100.0
        ]

        var theRecordingUrl = "/Users/myMbp/Desktop/test.wav" // !!! #### ammend the url for testing #### !!!
        var theRecordingUrlAsUrl = NSURL(string: theRecordingUrl)!
        println(theRecordingUrlAsUrl) // still looks good before crash

        var recorderError: NSError?
        recorder = AVAudioRecorder(URL: theRecordingUrlAsUrl, settings: recordSettings, error: &recorderError) // with the global recorder var it crashes here
        if let e = recorderError {
            println(e.localizedDescription)
        } else {
            recorder.delegate = self
            recorder.meteringEnabled = true
            if recorder.prepareToRecord() {
                println("recording prepared")
            }else{
                println("fialed to prepare recordeing")
            }
            if recorder.record() {
                println("started recording")
            }else{
                println("fialed to start recordeing")
            }
        }

    }


    @IBAction func stopRecording(sender: AnyObject) {
        recorder.stop()
    }



}

Answer 1

经过大量实验，发现答案是，我必须这样声明全局记录器变量：

var recorder:AVAudioRecorder!