Android 设置GridLayoutManager的完整跨度

我必须创建一个异构的

RecyclerView

。默认列数为2，但有些项目需要全宽。我在使用StaggedGridLayoutManager时使用它，如下所示：

    @Override
    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
        int viewType = getItemViewType(position);
        FeedItems currentItem = getItem(position);
        StaggeredGridLayoutManager.LayoutParams layoutParams = (StaggeredGridLayoutManager.LayoutParams) holder.itemView.getLayoutParams();
        switch (viewType) {
            case ITEM_TYPE_HEADER:
                final HeaderItem headerItem = currentItem.getHeaderItem();
                layoutParams.setFullSpan(true);
        }
    }

mLayoutManager = new GridLayoutManager(getActivity(), 2);
mLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
        @Override
        public int getSpanSize(int position) {
            switch(mAdapter.getItemViewType(position)){
                case 1:
                    return 1;
                case 2:
                    return 2;
                default:
                    return -1;
            }
        }
    });

mRecyclerView.setLayoutManager(mLayoutManager);

如何对GridLayoutManager执行相同的操作，在GridLayoutManager中，我可以轻松切换基于不同视图类型的跨度？

有一种方法。像这样使用它：

    @Override
    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
        int viewType = getItemViewType(position);
        FeedItems currentItem = getItem(position);
        StaggeredGridLayoutManager.LayoutParams layoutParams = (StaggeredGridLayoutManager.LayoutParams) holder.itemView.getLayoutParams();
        switch (viewType) {
            case ITEM_TYPE_HEADER:
                final HeaderItem headerItem = currentItem.getHeaderItem();
                layoutParams.setFullSpan(true);
        }
    }

mLayoutManager = new GridLayoutManager(getActivity(), 2);
mLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
        @Override
        public int getSpanSize(int position) {
            switch(mAdapter.getItemViewType(position)){
                case 1:
                    return 1;
                case 2:
                    return 2;
                default:
                    return -1;
            }
        }
    });

mRecyclerView.setLayoutManager(mLayoutManager);

---

这必须在将适配器设置为recyclerView之前或之后完成？通常，应在设置

recyclerView.adapter

之前设置

LayoutManager

。