快速锁定屏幕上的命令中心洗涤器答案

【问题标题】：command center Scrubber on lock screen swift快速锁定屏幕上的命令中心洗涤器
【发布时间】：2018-07-11 14:55:14
【问题描述】：

我正在尝试向命令中心锁定屏幕添加洗涤器，我收到此错误无法分配给值：函数调用返回不可变值我不知道这是什么意思。任何帮助将不胜感激。

这就是我试图改变位置的方式

commandCenter.changePlaybackPositionCommand.addTarget(handler: {
        (event) in
        let event = event as! MPChangePlaybackPositionCommandEvent
        self.player.currentTime() = event.positionTime  // ERROR
        return MPRemoteCommandHandlerStatus.success
    })

【问题讨论】：

标签： swift xcode mpremotecommandcenter

【解决方案1】：

我认为您的播放器属性是 AVPlayer (???)，如果是这样，您想使用 seek 函数设置 currentTime，而不是设置函数的返回值...

self.player.seek(to: CMTimeMakeWithSeconds(event.positionTime, 1000000))

【讨论】：

【解决方案2】：

首先，您必须设置 nowPlaying 元数据，并在您更改任何内容时调用它。

//MARK: setupNowPlaying----------------------------------
func setupNowPlaying() {
    // Define Now Playing Info
    var nowPlayingInfo = [String : Any]()
    nowPlayingInfo[MPMediaItemPropertyTitle] = self.nowPlayingString
    let image = UIImage(named: "Somni-lockLogo")! // this is the image you want to see on the lock screen
    let artwork = MPMediaItemArtwork.init(boundsSize: image.size,
                                          requestHandler: { (size) -> UIImage in
        return image
    })
    nowPlayingInfo[MPNowPlayingInfoPropertyElapsedPlaybackTime] = self.player.currentTime
    nowPlayingInfo[MPMediaItemPropertyPlaybackDuration] = self.player.duration
    nowPlayingInfo[MPNowPlayingInfoPropertyPlaybackRate] = player.rate
    //MARK: now playing
    nowPlayingInfo[MPMediaItemPropertyArtwork] = artwork
    nowPlayingInfo[MPMediaItemPropertyArtist ] = self.nowPlayingTitle
    // other metadata exists, check the documentation
  //  nowPlayingInfo[MPMediaItemPropertyArtist] = "David Bowie"
  //  nowPlayingInfo[MPMediaItemPropertyComposer] = "Bill Gates"
    
    // Set the metadata
    MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo
}

然后您需要设置远程传输控件以启用您需要的功能，例如播放暂停跳过等这是我的功能的开始，它启用东西并包含代码以使洗涤器工作

    func setupRemoteTransportControls() {
    // Get the shared MPRemoteCommandCenter
    let commandCenter = MPRemoteCommandCenter.shared()
    commandCenter.playCommand.isEnabled = true
    commandCenter.pauseCommand.isEnabled = true
     let skipBackwardIntervalCommand: MPSkipIntervalCommand? = commandCenter.skipBackwardCommand
    let skipForwardIntervalCommand: MPSkipIntervalCommand? = commandCenter.skipForwardCommand
    let seekForwardCommand: MPRemoteCommand? = commandCenter.seekForwardCommand
    let seekBackwardCommand: MPRemoteCommand? = commandCenter.seekBackwardCommand
    seekForwardCommand?.isEnabled = true
    seekBackwardCommand?.isEnabled = true
   
    skipBackwardIntervalCommand!.isEnabled = true
    skipForwardIntervalCommand!.preferredIntervals = [60]
    skipBackwardIntervalCommand!.preferredIntervals = [60]
    commandCenter.changePlaybackPositionCommand.isEnabled = true
    
    commandCenter.changePlaybackPositionCommand.addTarget
        { (event: MPRemoteCommandEvent) -> MPRemoteCommandHandlerStatus in
            let event = event as! MPChangePlaybackPositionCommandEvent
            print("change playback",event.positionTime)
            self.player.currentTime = event.positionTime
            self.setupNowPlaying()
            return .success
        }

// 等等，无论你想使用什么都需要一个处理程序，你需要在处理程序中将事件类型设置为正确的类型。

【讨论】：