Swift2 从AVPlayer设置MPNowPlayingFoCenter持续时间？

我正在尝试设置MPNowPlayingFocenter，大多数键值对工作正常，但播放时间存在某种问题

let mpic = MPNowPlayingInfoCenter.defaultCenter()    

mpic.nowPlayingInfo = [
    MPMediaItemPropertyArtwork:albumArtWork,
    MPMediaItemPropertyTitle:titleString,
    MPMediaItemPropertyArtist:artistName,
    MPMediaItemPropertyPlaybackDuration:99,
    MPNowPlayingInfoPropertyElapsedPlaybackTime:String(stringInterpolationSegment:self.myPlayer.currentItem?.currentTime()),
    MPNowPlayingInfoPropertyPlaybackRate:1.0
]

这会起作用，信息中心将正确开始计数

只要我尝试一下

MPMediaItemPropertyPlaybackDuration:String(stringInterpolationSegment:self.myPlayer.currentItem?.duration())

它将失败。我应该把时间转换成双倍吗？还有其他我应该访问的属性吗？

试试这个

    let elapsedTime = NSNumber(double : CMTimeGetSeconds(AudioAvPlayer.currentItem!.currentTime()))
    let keys = NSArray(objects:
        MPMediaItemPropertyTitle,
        MPMediaItemPropertyArtist,
        MPMediaItemPropertyPlaybackDuration,
        MPNowPlayingInfoPropertyPlaybackRate,
        MPNowPlayingInfoPropertyElapsedPlaybackTime)
    let values = NSArray (objects:
        m_PlayContent.Title,
        m_PlayContent.Artist,
        m_PlayContent.Duration,
        NSNumber(integer: 1),
        elapsedTime)
    let mediaInfo = NSDictionary(objects: values as [AnyObject], forKeys: keys as! [NSCopying])
    MPNowPlayingInfoCenter.defaultCenter().nowPlayingInfo = mediaInfo as [NSObject : AnyObject]

持续时间应为String/like:02:24

    let elapsedTime = NSNumber(double : CMTimeGetSeconds(AudioAvPlayer.currentItem!.currentTime()))
    let keys = NSArray(objects:
        MPMediaItemPropertyTitle,
        MPMediaItemPropertyArtist,
        MPMediaItemPropertyPlaybackDuration,
        MPNowPlayingInfoPropertyPlaybackRate,
        MPNowPlayingInfoPropertyElapsedPlaybackTime)
    let values = NSArray (objects:
        m_PlayContent.Title,
        m_PlayContent.Artist,
        m_PlayContent.Duration,
        NSNumber(integer: 1),
        elapsedTime)
    let mediaInfo = NSDictionary(objects: values as [AnyObject], forKeys: keys as! [NSCopying])
    MPNowPlayingInfoCenter.defaultCenter().nowPlayingInfo = mediaInfo as [NSObject : AnyObject]

持续时间应为String/like:02:24