exception can remove observer #116
Description
i got this error, please help:
code:
@objc fileprivate func startLoading() {
self.updateByContentOffset()
if self.presentedViewController != nil {
return
}
print("play : \(mmPlayerLayer.playUrl)")
// start loading video
mmPlayerLayer.resume()
}
fileprivate func updateByContentOffset() {
if let path = findFirstMediaCellVisible(), self.presentedViewController == nil {
self.updateCell(at: path)
}
}
private func findFirstMediaCellVisible() -> IndexPath? {
let visible = messagesCollectionView.indexPathsForVisibleItems
guard visible.count > 0 else { return nil }
return visible.first(where: { messagesCollectionView.cellForItem(at: $0) is MediaMessageCell} )
}
func updateCell(at indexPath: IndexPath) {
print("updateCell: \(NSStringFromClass(messagesCollectionView.cellForItem(at: indexPath)!.classForCoder))")
let message = messageList[indexPath.section]
guard case let .video(videoItem) = message.kind else { return }
if let cell = messagesCollectionView.cellForItem(at: indexPath) as? MediaMessageCell {
// this thumb use when transition start and your video dosent start
// mmPlayerLayer.thumbImageView.image = cell.im
// set video where to play
print("set mm for index: \(indexPath) - \(message.sender.displayName)")
mmPlayerLayer.playView = cell.imageView
mmPlayerLayer.set(url: videoItem.url)
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
offsetObservation = messagesCollectionView.observe(\.contentOffset, options: [.new]) { [weak self] (_, value) in
guard let self = self, self.presentedViewController == nil else {return}
NSObject.cancelPreviousPerformRequests(withTarget: self)
self.perform(#selector(self.startLoading), with: nil, afterDelay: 0.2)
}
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
NotificationCenter.default.removeObserver(self)
mmPlayerLayer.player?.pause()
}