为什么我的时间UILabels从暂停状态恢复播放时跳过2秒？

我有一个奇怪的问题使用MPMoviePlayerController 。 我有一个currentTimeLabel表示当前的播放时间， endTimeLabel表示剩余的播放时间。 使用NSTimer每1秒就会触发更新标签的function。

这与video播放时UISlider增加的UISlider一致。 但是，问题是，随着video播放，我点击暂停button，当我再次点击播放button时，我的currentTimeLabel和endTimeLabel从上次停止的地方跳过2秒。

以下是提供的代码：

 override func viewDidLoad() { super.viewDidLoad() print("viewDidLoad") NSNotificationCenter.defaultCenter().addObserver( self, selector: "moviePlayerPlaybackStateDidChangeNotification:", name: MPMoviePlayerPlaybackStateDidChangeNotification, object: nil) NSNotificationCenter.defaultCenter().addObserver( self, selector: "moviePlayerLoadStateDidChangeNotification:", name: MPMoviePlayerLoadStateDidChangeNotification, object: nil) setUpVideoPlayer() isPlaybackSliderTouched = false isPauseButtonTouched = false } override func viewDidAppear(animated: Bool) { super.viewDidAppear(true) print("viewDidAppear") timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "updatePlaybackSlider", userInfo: nil, repeats: true) playPauseButton.addTarget(self, action: "onClick:", forControlEvents: .TouchUpInside) } func convertSecondsToHHMMSS(seconds: Double) -> String { let time: Int = Int( floor(seconds) ) print("time = \(time)") // Convert to hours let hh: Int = time / 3600 // Convert to minutes let mm: Int = (time / 60) % 60 // Convert to seconds let ss: Int = time % 60 print("seconds = \(ss)") if hh > 0 { return String(format: "%02d:%02d:%02d", hh, mm, ss) } else { return String(format: "%02d:%02d", mm, ss ) } } func updatePlaybackSlider() { if isPlaybackSliderTouched == false { print("PLAYBACKSLIDER IS NOT TOUCHED!") print("youtubeVideoPlayer.moviePlayer.currentPlaybackTime = \(youtubeVideoPlayer.moviePlayer.currentPlaybackTime)") print("youtubeVideoPlayer.moviePlayer.duration = \(youtubeVideoPlayer.moviePlayer.duration)") let sliderValue: Float = Float(youtubeVideoPlayer.moviePlayer.currentPlaybackTime / youtubeVideoPlayer.moviePlayer.duration) print("sliderValue = \(sliderValue)") if !sliderValue.isNaN { self.playbackSlider.setValue(sliderValue, animated: true) self.currentTimeLabel.text = self.convertSecondsToHHMMSS(self.youtubeVideoPlayer.moviePlayer.currentPlaybackTime) self.endTimeLabel.text = "-" + self.convertSecondsToHHMMSS(self.youtubeVideoPlayer.moviePlayer.duration - self.youtubeVideoPlayer.moviePlayer.currentPlaybackTime) print("currentTimeLabel.text = \(currentTimeLabel.text)") print("endTimeLabel.text = \(endTimeLabel.text)") } } } func onClick(sender: UIButton) { print("onClick") if sender == playPauseButton { print("playPauseButton touched") if sender.selected { print("player play") timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "updatePlaybackSlider", userInfo: nil, repeats: true) isPauseButtonTouched = false youtubeVideoPlayer.moviePlayer.play() sender.selected = false } else { print("player paused") isPauseButtonTouched = true timer.invalidate() timer = nil youtubeVideoPlayer.moviePlayer.pause() sender.selected = true } } } func moviePlayerPlaybackStateDidChangeNotification(notification: NSNotification) { print("moviePlayerPlaybackStateDidChangeNotification") let state: MPMoviePlaybackState = youtubeVideoPlayer.moviePlayer.playbackState switch state { case MPMoviePlaybackState.Stopped: print("stopped") break case MPMoviePlaybackState.Interrupted: print("interrupted") break case MPMoviePlaybackState.SeekingForward: print("forward") break case MPMoviePlaybackState.SeekingBackward: print("backward") break case MPMoviePlaybackState.Paused: print("paused") break case MPMoviePlaybackState.Playing: print("playing") break } } func moviePlayerLoadStateDidChangeNotification(notification: NSNotification) { print("moviePlayerLoadStateDidChangeNotification") let state: MPMovieLoadState = youtubeVideoPlayer.moviePlayer.loadState switch state { case MPMovieLoadState.Playable: print("playing") break case MPMovieLoadState.PlaythroughOK: print("PlaythroughOK") break case MPMovieLoadState.Stalled: print("stalled") break case MPMovieLoadState.Unknown: print("unknown") break default: break } } 

这是几秒钟video播放的输出：

 viewDidLoad setUpVideoPlayer viewDidAppear moviePlayerLoadStateDidChangeNotification time = 0 seconds = 0 time = 29 seconds = 29 playing moviePlayerLoadStateDidChangeNotification moviePlayerPlaybackStateDidChangeNotification playing PLAYBACKSLIDER IS NOT TOUCHED! youtubeVideoPlayer.moviePlayer.currentPlaybackTime = 0.0 youtubeVideoPlayer.moviePlayer.duration = 29.8833333333333 sliderValue = 0.0 time = 0 seconds = 0 time = 29 seconds = 29 currentTimeLabel.text = Optional("00:00") endTimeLabel.text = Optional("-00:29") PLAYBACKSLIDER IS NOT TOUCHED! youtubeVideoPlayer.moviePlayer.currentPlaybackTime = 0.484628237 youtubeVideoPlayer.moviePlayer.duration = 29.8833333333333 sliderValue = 0.016255 time = 0 seconds = 0 time = 29 seconds = 29 currentTimeLabel.text = Optional("00:00") endTimeLabel.text = Optional("-00:29") PLAYBACKSLIDER IS NOT TOUCHED! youtubeVideoPlayer.moviePlayer.currentPlaybackTime = 1.484112736 youtubeVideoPlayer.moviePlayer.duration = 29.8833333333333 sliderValue = 0.0496863 time = 1 seconds = 1 time = 28 seconds = 28 currentTimeLabel.text = Optional("00:01") endTimeLabel.text = Optional("-00:28") onClick playPauseButton touched player paused moviePlayerPlaybackStateDidChangeNotification paused isPauseButtonTouched = true onClick playPauseButton touched player play moviePlayerPlaybackStateDidChangeNotification playing PLAYBACKSLIDER IS NOT TOUCHED! youtubeVideoPlayer.moviePlayer.currentPlaybackTime = 3.34555252 youtubeVideoPlayer.moviePlayer.duration = 29.8833333333333 sliderValue = 0.111982 time = 3 seconds = 3 time = 26 seconds = 26 currentTimeLabel.text = Optional("00:03") endTimeLabel.text = Optional("-00:26") moviePlayerPlaybackStateDidChangeNotification paused 

正如你在输出中看到的， currentTimeLabel.text = Optional("00:01")是我点击暂停的时间。 当我点击播放，输出应该是currentTimeLabel.text = Optional("00:02") ，但它显示currentTimeLabel.text = Optional("00:03") 。 我的endTimeLabel也跳过了2秒。

为什么会发生这种情况，我该如何解决？

谢谢

Answer 1

恢复播放状态下的定时器。 可能解决这个问题。

 case MPMoviePlaybackState.Playing:{ print("playing") timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "updatePlaybackSlider", userInfo: nil, repeats: true) break }