MPRemoteCommandCenter play/pause Flashing when touched - swift

Question

i'm working on music player app that written in Swift, audio streams with AVPlayer and everything is fine
but when i tried to add MPRemoteCommandCenter to my app there was a lot of bug that i dont know even why this happend
link to video that describes my problem
AVPlayer Implemented like:
func setupPlayer() {
let item = AVPlayerItem(url: musicURL)
self.player = AVPlayer.init(playerItem: item)
self.player.play()
self.player.volume = 1
self.player.addPeriodicTimeObserver(forInterval: CMTimeMakeWithSeconds(1, preferredTimescale: 1), queue: DispatchQueue.main, using: { (time) in
if self.player.currentItem?.status == .readyToPlay {
self.reloadNowPlayingInfo()
let currentTime = self.player.currentTime().seconds
self.playingTime.text = currentTime.getTimeString()
self.playerSlider.value = currentTime/duration
}
})
}
func reloadNowPlayingInfo() {
var info = [String : Any]()
info[MPMediaItemPropertyTitle] = self.titleText
info[MPMediaItemPropertyArtwork] = MPMediaItemArtwork.init("some image")
info[MPMediaItemPropertyPlaybackDuration] = seconds
info[MPNowPlayingInfoPropertyElapsedPlaybackTime] = currentSecs
info[MPMediaItemPropertyArtist] = "Artist name"
MPNowPlayingInfoCenter.default().nowPlayingInfo = info
}
and for command center,
MPRemoteCommandCenter Implemented like:
func setupCommandCenter() {
let commandCenter = MPRemoteCommandCenter.shared()
commandCenter.playCommand.isEnabled = true
commandCenter.pauseCommand.isEnabled = true
commandCenter.playCommand.addTarget(self, action: #selector(self.playCommand(_:)))
commandCenter.pauseCommand.addTarget(self, action: #selector(self.pauseCommand(_:)))
}
#objc func playCenter(_ action: MPRemoteCommandEvent) {
self.state = .play
self.playBtn.setBackgroundImage("some image"), for: .normal)
self.player.play()
self.fetchTracks()
}
#objc func pauseCenter(_ action: MPRemoteCommandEvent) {
self.state = .pause
self.playBtn.setBackgroundImage("some image"), for: .normal)
self.player.pause()
self.fetchTracks()
}

Answer 1

In addition to the code you've presented you might also have called the following somewhere in your app delegate:
UIApplication.shared.beginReceivingRemoteControlEvents()
Doing this in addition to using MPRemoteCommandCenter.shared() seems to cause a race condition.
According to Apple's documentation:
In iOS 7.1 and later, use the shared MPRemoteCommandCenter object to register for remote control events. You do not need to call this method when using the shared command center object.
This method starts the delivery of remote control events using the responder chain.
Remove that method from your app delegate and you should be fine.

Answer 2

If you add 2 observer to your code to receive player notifications. you may see lag or jump in player lock screen.
avoid adding observer and once a target.
commandCenter.playCommand.addTarget(self, action: #selector(self.playCommand(_:)))
only once. and remove it when u dont wanted