ios - MPMusicPlayerControllerNowPlayingItemDidChange 是不可预测的

Question

基本上 MPMusicPlayerControllerNowPlayingItemDidChange 是非常不可预测的。有时它会被调用一次，有时会被调用两次，有时它会在歌曲播放时随机调用。我需要找到一种方法来忽略虚假通知调用，只处理音乐项目实际上从一个项目更改为另一个项目的时间。

我尝试查看 currentPlaybackTime == 0 是否然后才处理通知，但有时歌曲更新并且它们的播放时间不是 0。我还尝试创建一个缓冲区，只允许新项目在旧项目之后更新某个时间项目已更新，但这确实不可靠，因为在极少数情况下，当我在音乐播放器队列中添加新歌曲时，通知会在歌曲中间发送。

@objc static func appleMusicItemDidUpdate() {
        let spController = AppDelegate.songPlayerController
        let item = AppDelegate.appleMusicPlayer.nowPlayingItem

        print("got new item:", item?.title ?? "no title")

        if let item = item, let title = item.title, title != "Loading...", AppDelegate.appleMusicPlayer.currentPlaybackTime == 0 {
            if item.isCloudItem && item.playbackStoreID != "0" && item.playbackStoreID != "" {
                print("test1")
                if /*other specific check (not important)*/ true {
                    print("handling notification")
                }
            } else {
                print("test5")
                spController.lastUpdate = Date().timeIntervalSince1970
                print("handling notification")
            }
        } else {
            print("item did not pass check:")
            if item == nil {
                print("item was nil")
            }

            if item?.title == nil {
                print("title was nil")
            }

            if item?.title == "Loading..." {
                print("item was loading")
            }

            if AppDelegate.appleMusicPlayer.currentPlaybackTime >= 0.0001 {
                print("current playback time was", AppDelegate.appleMusicPlayer.currentPlaybackTime)
            }

            if !spController.passesBufferCheck() {
                print("did not pass buffer check")
            }

            print("")
        }

The notification gets called randomly and sometimes gets called multiple times when a song is updated and I can't find a reliable way to check for an actual update.

标签： iosswiftmpmediaplayercontroller