android – 带有GridLayoutManager的RecyclerView和带有不同viewHolder的第一个元素

我需要在两行上创建一个带有GridLayoutManager的recyclerView,并且第一个元素要比其余元素大.结果应如下所示：

我设法实现了这个目标,但是以一种非传统的方式.在我的recyclerView适配器中,我使用不同的viewHolder作为第一个元素,一个更大的元素.那将是一个很好的解决方案,但第二个元素将低于第一个元素.所以我做了一个技巧,给予recyclerView一个与第一个元素相同的固定高度,这样第一个元素和第二个元素重叠,我只是让第二个元素的可见性消失了.

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    switch (viewType) {
        case 0:
            final View view = inflater.inflate(R.layout.big_item, parent, false);
            return new BigViewHolder(view);
        case 2:
            final View view2 = inflater.inflate(R.layout.normal_item, parent, false);
            return new NormalViewHolder(view2);
        default:
            return null;
    }
}

@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
    if (position == 1) {
        holder.itemView.setVisibility(View.GONE);
    }}

@Override
public int getItemViewType(int position) {
    if (position == 0) {
        return 0;
    } else return 2;
}

但我并不特别喜欢这种方法.有人对此有更好的想法吗？

解决方法:

经过一番挖掘和咨询,我得到了一个非常好的结果.我将在下面发布：

首先,适配器看起来应该像我在问题中提到的那样,没有隐藏第二个元素：

 public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    public static final int TYPE_FIRST_ITEM = 0;
    public static final int TYPE_ITEM = 1;

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        switch (viewType) {
            case TYPE_FIRST_ITEM:
                final View view = inflater.inflate(R.layout.big_item, parent, false);
                return new BigViewHolder(view);
            case TYPE_ITEM:
                final View view2 = inflater.inflate(R.layout.normal_item, parent, false);
                return new NormalViewHolder(view2);
            default:
                return null;
        }
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        switch (holder.getItemViewType()) {
            case TYPE_FIRST_ITEM:
                BigViewHolder bigViewHolder = (BigViewHolder) holder;
                // Do what you need for the first item
                break;
            case TYPE_ITEM:
                NormalViewHolder normalViewHolder = (NormalViewHolder) holder;
                // Do what you for the other items
                break;
        }
    }

    @Override
    public int getItemViewType(int position) {
        if (position == 0) {
            return TYPE_FIRST_ITEM;
        } else return TYPE_ITEM;
    }

    final class NormalViewHolder extends RecyclerView.ViewHolder {
        public NormalViewHolder(View itemView) {
            super(itemView);
        }
        // find your views here
    }

    final class BigViewHolder extends RecyclerView.ViewHolder {
        public BigViewHolder(View itemView) {
            super(itemView);
        }
        // find your views here
    }
}

其次,布局管理器应该实现一个监听器来指定在特定位置应该有多少跨度(行)：

RecyclerView mRecyclerView = view.findViewById(R.id.my_recycler_view);
        MyAdapter mAdapter = new MyAdapter();
        GridLayoutManager mLayoutManager = new GridLayoutManager(getActivity(), 2, LinearLayoutManager.HORIZONTAL, false);
        mLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
            @Override
            public int getSpanSize(int position) {
                switch(mAdapter.getItemViewType(position)){
                    case MyAdapter.TYPE_FIRST_ITEM:
                        return 2;
                    case MyAdapter.TYPE_ITEM:
                        return 1;
                    default:
                        return -1;
                }
            }
        });
        mRecyclerView.setAdapter(mAdapter);
        mRecyclerView.setLayoutManager(mLayoutManager);

希望它也能帮助别人.感谢Mike M.的支持.

标签：android,android-recyclerview,gridlayoutmanager,android-layout
来源： https://codeday.me/bug/20190727/1550793.html