iOS视频列表滚动自动播放的实现（Swift）_秋海一刀_ios 滑动播放

未知 02-07 6858

一、思路

首先，我们在视频列表中播放视频，并不一定需要给每个cell都添加上一个player，这样既要控制每个cell的player，同时还占用内存。我们只需用一个player就可以实现在列表中的某个区域播放视频，大致思路如下：

1.监听列表的滚动。

2.在列表设置一个最高点，一个最低点，从而确定一个播放范围。

3.当用户滑动列表使cell进入播放范围时，将player添加到要播放的控件中进行视频播放。

4.滑动到下一个要播放的cell时，移除当前正在播放或者离开屏幕的player，将player添加到新的播放控件中。

二、具体实现 1.协议VideoPlayable protocol VideoPlayable: UIView { ///播放器容器 var viewToContainVideo: UIView {get} ///设置播放url var urlToPlay: URL? {get} ///播放状态改变 func videoStatusChanged(changeTo isPlaying: Bool) ///播放时间改变 func videoPlayTimeChanged(changeTo playTime: Float64) }

继承VideoPlayable的控件即可在上面播放视频，同时可以根据需求去声明属性和方法，比如这里我需要去获取视频的播放进度，就声明了?videoPlayTimeChanged监听视频的播放

2.协议VideoListPlayable protocol VideoListPlayable: UIScrollView { var visibleViews: [VideoPlayable] {get} } extension UITableView: VideoListPlayable { var visibleViews: [VideoPlayable] { let views: [VideoPlayable] = visibleCells.compactMap({ $0 as? VideoPlayable }) return views } } extension UICollectionView: VideoListPlayable { var visibleViews: [VideoPlayable] { let views: [VideoPlayable] = visibleCells.compactMap({ $0 as? VideoPlayable }) return views } }

继承了VideoListPlayable的控件在监听列表滚动时，即可对视频播放进行处理。

3.创建Manager class GXRCWVideoListAutoPlayManager { static let shared = GXRCWVideoListAutoPlayManager() private var playerVC: AVPlayerViewController = AVPlayerViewController() private var preOffsetY: CGFloat = 0 private var currentPlayingView: VideoPlayable? private init() { playerVC.player = AVPlayer() // playerVC.showsPlaybackControls = false playerVC.view.backgroundColor = .clear //暂停播放器 _ = NotificationCenter.default.rx .notification(Notification.Name(NotificationNameInfo.kPuseVideoPlayer)) // .take(until: self.rx.deallocated) .subscribe(onNext: { _ in self.playerVC.player?.pause() }) } func scrollViewDidScroll(_ scrollView: VideoListPlayable) { let currentOffsetY = scrollView.contentOffset.y //设置播放范围 let minY = scrollView.frame.height * 0.2 let maxY = scrollView.frame.height * 0.75 // 获取在 scrollView 自动播放区域内的视频 let autoPlayableViews = scrollView.visibleViews.filter { view in guard let relativeRect = relativeRect(view: view.viewToContainVideo, relativeTo: scrollView), view.urlToPlay != nil else {return false} let containerCenterY = relativeRect.minY + relativeRect.height / 2 return (containerCenterY > minY && containerCenterY < maxY) } guard let first = autoPlayableViews.first else { // 没有需要自动播放的视频 // 移除当前正在离开/已经离开屏幕的视频 removeCurrentVideoIfLeavingScreen(scrollView: scrollView) preOffsetY = currentOffsetY return } // 取出需要自动播放的视频 let viewToPlay: VideoPlayable = autoPlayableViews.reduce(first) { (result, view) in let isScrollToUpper = currentOffsetY < preOffsetY return result.frame.maxY > view.frame.maxY ? (isScrollToUpper ? view : result) : (isScrollToUpper ? result : view) } if let currentPlayingView = currentPlayingView, viewToPlay as UIView == currentPlayingView { // 满足条件的视频正在播放中 preOffsetY = currentOffsetY return } removeCurrentVideo(on: scrollView) addPlayerView(to: viewToPlay, on: scrollView) preOffsetY = currentOffsetY } func play(at videoView: VideoPlayable, on scrollView: VideoListPlayable) { removeCurrentVideo(on: scrollView) addPlayerView(to: videoView, on: scrollView) } }

manager是连通列表和cell实现播放的中间者，也是实现列表视频播放的核心，如需修改播放的范围修改minY和maxY的值即可。

4.私有方法 private extension GXRCWVideoListAutoPlayManager { func relativeRect(view: UIView, relativeTo scrollView: VideoListPlayable) -> CGRect? { // 计算 view 相对于 scrollView 的位置 guard let scrollViewSuperView = scrollView.superview, let containerSuperview = view.superview else {return nil} let containerViewRect = containerSuperview.convert(view.frame, to: scrollViewSuperView) let relativeRect = CGRect(origin: CGPoint(x: containerViewRect.minX - scrollView.frame.minX, y: containerViewRect.minY - scrollView.frame.minY), size: containerViewRect.size) return relativeRect } func addPlayerView(to view: VideoPlayable, on scrollView: VideoListPlayable) { guard let url = view.urlToPlay else { return } let avItem = AVPlayerItem(url: url) let avPlayer = AVPlayer(playerItem: avItem) playerVC.player = avPlayer avPlayer.isMuted = true//默认开启静音 avPlayer.play() avPlayer.addPeriodicTimeObserver(forInterval: CMTime(value: CMTimeValue(1.0), timescale: CMTimeScale(1.0)), queue: .main) { time in //监听视频播放进度 view.videoPlayTimeChanged(changeTo: CMTimeGetSeconds(time)) } view.videoStatusChanged(changeTo: true) let containerView = view.viewToContainVideo containerView.addSubview(playerVC.view) playerVC.view.translatesAutoresizingMaskIntoConstraints = false playerVC.view.topAnchor.constraint(equalTo: containerView.topAnchor).isActive = true playerVC.view.bottomAnchor.constraint(equalTo: containerView.bottomAnchor).isActive = true playerVC.view.leftAnchor.constraint(equalTo: containerView.leftAnchor).isActive = true playerVC.view.rightAnchor.constraint(equalTo: containerView.rightAnchor).isActive = true currentPlayingView = view playerVC.showsPlaybackControls = true } func removeCurrentVideoIfLeavingScreen(scrollView: VideoListPlayable) { playerVC.showsPlaybackControls = false guard let view = currentPlayingView, let relativeRect = relativeRect(view: view, relativeTo: scrollView) else { return } let currentOffsetY = scrollView.contentOffset.y let containerCenterY = relativeRect.minY + relativeRect.height / 2 if (currentOffsetY > preOffsetY && containerCenterY <= 0) || (currentOffsetY < preOffsetY && containerCenterY >= scrollView.frame.height) { removeCurrentVideo(on: scrollView) } } func removeCurrentVideo(on scrollView: VideoListPlayable) { playerVC.player = nil playerVC.view.removeFromSuperview() currentPlayingView?.videoStatusChanged(changeTo: false) currentPlayingView = nil } }

三、使用示例 1.列表监听滚动 extension DiscoverSearchDynamicsListView: UIScrollViewDelegate{ func scrollViewDidScroll(_ scrollView: UIScrollView) { GXRCWVideoListAutoPlayManager.shared.scrollViewDidScroll(self) } }

2.cell实现VideoPlayable extension DiscoverSearchDynamicsListVideoCell: VideoPlayable{ var viewToContainVideo: UIView{ return contentView } var urlToPlay: URL? { return URL(string: getM.videoUrl) } func videoStatusChanged(changeTo isPlaying: Bool) { backIV.isHidden = isPlaying } func videoPlayTimeChanged(changeTo playTime: Float64) { getM.videoCurrentTime = playTime } } 3.效果图?

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