问MPRemoteCommandCenter的问题
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Stack Overflow用户

提问于 2017-05-28 17:51:06

回答 1查看 725关注 0票数 1

我对MPRemoteCommandCenter有两个问题：

1)当我更改歌曲时，遥控器删除先前的歌曲图像，制作默认歌曲图像，制作下一首歌曲图像。我不想看到默认的图像。我花了几个时间想出解决办法。

( 2)当AVPlayer是实时流声音时，遥控器就会变成不活动的圆圈箭头(成圆周箭头为15，这意味着什么？)

下面是我播放声音的代码：

public func playAVSound(trackName : String) -> String {
    let path = _findPath(trackName: trackName);
    if (path == "") {
        return "getting url"
    }
    if (self.AVPlayerVC.player == nil) {
        print("Init remote control events...")
        UIApplication.shared.beginReceivingRemoteControlEvents()
        let commandCenter = MPRemoteCommandCenter.shared()
        commandCenter.nextTrackCommand.isEnabled = true
        commandCenter.nextTrackCommand.addTarget(self, action:#selector(self.next))
        commandCenter.previousTrackCommand.isEnabled = true
        commandCenter.previousTrackCommand.addTarget(self, action:#selector(self.previous))
    }
    if (self.AVPlayerVC.player != nil && self.play_info.trackName == trackName) {
        if (self.play_info.paused!) {
            self.AVPlayerVC.player?.play()
            self.updatePlayInfo(number: Global.PlayList.find_by_trackName(trackName: trackName), trackName: trackName, path: path, paused: false)
            return "continue"
        } else {
            self.AVPlayerVC.player?.pause()
            self.play_info.paused = true
            return "pause"
        }
    }
    let nsurl = NSURL(string: path)
    if let url = nsurl {
        print("Play AV from : \(url)")
        let item = AVPlayerItem(url: url as URL)
        if (self.AVPlayerVC.player?.currentItem == nil) {
            self.AvPlayer = AVPlayer(playerItem: item)
            self.AVPlayerVC.player = self.AvPlayer
            self.AVPlayerVC.player?.automaticallyWaitsToMinimizeStalling = false
        } else {
            self.AvPlayer?.replaceCurrentItem(with: item)
        }
        NotificationCenter.default.addObserver(self, selector: #selector(self.playerDidFinishPlaying), name: .AVPlayerItemDidPlayToEndTime, object: item)
        self.AVPlayerVC.player?.play()
        self.updatePlayInfo(number: Global.PlayList.find_by_trackName(trackName: trackName), trackName: trackName, path: path, paused: false)
        return "playing"
    } else {
        print ("Incorrect nsurl")
    }
    return "error"
}

private func _findPath (trackName: String) -> String {
    let n = Global.PlayList.find_by_trackName(trackName: trackName)
    var path = ""
    if (n >= 0) {
        let p_item = Global.PlayList.PlaylistItems[n];
        if (!p_item.fromData!) {
            if (p_item.playing_url == nil) {
                NetLib.makeTrackUrl(trackName: trackName, closure: self.playAVSound)
            } else {
                path = p_item.playing_url!
            }
        } else {
            path = NetLib.makePath(filename: p_item.filename!)
        }
    } else {
        print("Error find_path: \(trackName) was not found in playlist")
    }
    return path
}

这是代码，它改变了歌曲

    @objc private func previous() -> MPRemoteCommandHandlerStatus{
    var n = self.play_info.number! - 1;
    if (self.play_info.number == 0) {
        n = Global.PlayList.size() - 1;
    }
    NotificationCenter.default.post(name: NSNotification.Name(rawValue: "load"), object: nil)
    _ = self.playAVSound(trackName: Global.PlayList.PlaylistItems[n].trackName!)
    print("Previous song \(Global.PlayList.PlaylistItems[n].trackName!)")
    return .success
}