private void setTopView() {recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {@Overridepublic void onScrolled(RecyclerView t, int dx, int dy) {//标题栏底部的Y坐标int[] titleLocation = new int[2];rootLayout.getLocationOnScreen(titleLocation);int titleY = titleLocation[1] + rootLayout.getMeasuredHeight();//最顶部可见的位置int position = layoutManager.findFirstVisibleItemPosition();//第二个布局的顶部Y坐标BaseViewHolder viewHolder = (BaseViewHolder) recyclerView.findViewHolderForAdapterPosition(position + 1);View layout = viewHolder.getConvertView();int[] location = new int[2];layout.getLocationOnScreen(location);int y = location[1];//悬浮章的底部坐标int topBottom = titleY + topChapterLayout.getMeasuredHeight();RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, topChapterLayout.getMeasuredHeight());if (list.get(position) instanceof CourseDetail) {CourseDetail courseDetail = (CourseDetail) list.get(position);CourseDetail courseDetailAfter = (CourseDetail) list.get(position + 1);if (!TextUtils.isEmpty(courseDetail.getChapterTitle())) {params.topMargin = 0;topChapterLayout.setLayoutParams(params);topChapterLayout.setVisibility(View.VISIBLE);chapter.setText(courseDetail.getChapterTitle());switch (courseDetail.getChapterStatus()) {case 0:noComplete.setVisibility(View.VISIBLE);complete.setVisibility(View.GONE);break;case 1:complete.setVisibility(View.VISIBLE);noComplete.setVisibility(View.GONE);break;}if (null == courseDetailAfter) {return;}if (courseDetail.getChapterId() != courseDetailAfter.getChapterId()) {if (y <= topBottom) {int scrollY = y - topBottom;params.topMargin = scrollY;topChapterLayout.setLayoutParams(params);}}}} else {topChapterLayout.setVisibility(View.INVISIBLE);}}});
}