         }
     }
 
-    var audioPlayedDuration: NSTimeInterval = 0 {
+    private var audioPlayedDuration: NSTimeInterval = 0 {
         willSet {
 
             guard newValue != audioPlayedDuration else {

        }
    }

    @IBAction func playOrPauseAudio(sender: UIButton) {

        guard let voiceFileURL = voiceFileURL else {
            return


        nextButton.title = NSLocalizedString("Next", comment: "")

        displayLink = CADisplayLink(target: self, selector: "checkVoiceRecordValue:")
        displayLink.frameInterval = 6 // 频率为每秒 10 次
        displayLink.addToRunLoop(NSRunLoop.currentRunLoop(), forMode: NSRunLoopCommonModes)

