Android 列表视频滑动自动播放(实现思路)

1、列表（RecyclerView）中内容包含视频，列表在快速滑动时候，如果每个视频自动播放，会导致页面卡顿。我们优化思路，通过监听RecyclerView滑动状态，来实现当停止滑动时候，来播放视频

滑动监听：recyclerView.addOnScrollListener(this)

实现具体方法：onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState)

newState：

RecyclerView.SCROLL_STATE_IDLE: //滑动停止

RecyclerView.SCROLL_STATE_DRAGGING: //手指拖动

RecyclerView.SCROLL_STATE_SETTLING: //惯性滚动

这里只介绍SCROLL_STATE_IDLE来处理滑动停止，自动播放相关思路和逻辑

 public void startVideo() {//第一步：获取LinearLayoutManagerLinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();if (layoutManager != null) {//第二步：获取当前第一个显示itemView的position，并得到这条数据是否有视频int findFirstVisibleItemPosition = layoutManager.findFirstVisibleItemPosition();//第三步：获取当前itemView的 ViewHolder,并通过获取视频播放控件ViewHolder viewHolder = (ViewHolder) recyclerView.findViewHolderForAdapterPosition(findFirstVisibleItemPosition);VideoView videoView = viewHolder.itemView.findViewById(R.id.videoView);//计算视频播放控件，显示比例，当>=50%，则播放当前，否则寻找下一条显示item，播放Rect itemRect = new Rect();videoView.getLocalVisibleRect(itemRect);int visibleHeight = itemRect.bottom - itemRect.top;int totalHeight = videoView.getHeight();float visibleRatio = (float) visibleHeight / totalHeight;if (visibleRatio >= 0.5f) {//播放视频} else {//第二个显示视频//获取已显示最后一条数据positionint lastVisibleItemPosition = layoutManager.findLastVisibleItemPosition();int firstPosition = findFirstVisibleItemPosition + 1;if (firstPosition <= lastVisibleItemPosition) {//遍历,找到有视频的positionfor (int i = firstPosition; i < lastVisibleItemPosition; i++) {//当前有视频播放//计算视频播放控件，显示比例，当>=50%，则播放当前，否则寻找下一条显示item，播放viewHolder = (ViewHolder) recyclerView.findViewHolderForAdapterPosition(i);videoView = viewHolder.itemView.findViewById(R.id.videoView);itemRect = new Rect();videoView.getLocalVisibleRect(itemRect);visibleHeight = itemRect.bottom - itemRect.top;totalHeight = videoView.getHeight();visibleRatio = (float) visibleHeight / totalHeight;if (visibleRatio >= 0.5f) {//播放视频，结束循环return;}}}}}}

当

SCROLL_STATE_DRAGGING（SCROLL_STATE_DRAGGING）我们需要暂停已经在播放的视频，我已经知道播放的是哪个position

  public void stopVideo() {//当前播放视频角标，是否在播放，if (startPosition >= 0) {ViewHolder viewHolder = (ViewHolder) recyclerView.findViewHolderForAdapterPosition(startPosition);if (viewHolder != null) {VideoView videoView = viewHolder.itemView.findViewById(R.id.videoView);if (videoView != null) {videoView.pause();}//停止播放，设置再播放未-1，表示未有播放视频startPosition = -1;}}}