RecyclerView 添加多个头布局和脚布局:

test.jpg 昨天把recyclerview的基本封装写完了,如果还不知道链接的地址可以点这个,点这个重头开始,RecyclerView的起步封装,写的不好的地方还是希望大家纠正,如果有更好的提议希望大家随时@我,在此谢过各位大神了:话不多好正题开始了,恩恩,先平复下心情:

添加头布局和脚步:

只要是用过RecyclerView的估计大家都知道,这个东西不像ListView那样直接可以

• addHeaderView()或addFooterView(),removeHeaderView(),removeFooterView()
  所以今天就进入我们的正题,一千人就有一千个哈姆雷特,给RecyclerView添加头的方式各有各的方式:就我目前所见:基本类似就是三种:
• 上边用一个垂直的LinearLayout 里面动态的添加或者移除l
• 模仿ListView的添加头的方法,如果是这种就要去看ListView的源码了,不过我觉得这种添加方式不是特别好,只是个人建议,因为你还得去重写recyclerview,感觉还是稍稍的的有嗲麻烦
• 第三种,也是我接下我要写的这一种装饰者模式添加头,给这个对象额外的增加功能:
  一不开心就上代码:

/**
 * Created by fx on 2017/6/29.
 * 采用装饰着模式进行封装头部和尾部:
 */

public class HeaderAndFooterWrapper<k> extends RecyclerView.Adapter<BaseViewHolder> {
    private static final int BASE_ITEM_TYPE_HEADER = 100000;
    private static final int BASE_ITEM_TYPE_FOOTER = 200000;

    private SparseArray<View> mHeaderViews = new SparseArray<>();
    private SparseArray<View> mFootViews = new SparseArray<>();
    private BaseAdapter<k> mInnerAdapter;
    private static final int M_DEFAULT_NUMBER = -1;
    private static final String TAG = "HeaderAndFooterWrapper";

    //将我们自己的adapter 传进去:
    public HeaderAndFooterWrapper(BaseAdapter<k> adapter) {
        mInnerAdapter = adapter;
    }

    @Override
    public BaseViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        BaseViewHolder holder;
        if (mHeaderViews.get(viewType) != null) {
            holder = BaseViewHolder.creatBaseViewHolder(mHeaderViews.get(viewType));
            return holder;

        } else if (mFootViews.get(viewType) != null) {
            holder = BaseViewHolder.creatBaseViewHolder(mFootViews.get(viewType));
            return holder;
        }
        return mInnerAdapter.onCreateViewHolder(parent, viewType);
    }

    @Override
    public void onBindViewHolder(BaseViewHolder viewHolder, int position) {
        if (isHeaderViewPos(position)) {
            return;
        }
        if (isFooterViewPos(position)) {
            return;
        }
        mInnerAdapter.onBindViewHolder(viewHolder, position - getHeadersCount());
    }

    @Override
    public int getItemViewType(int position) {
        if (isHeaderViewPos(position)) {
            return mHeaderViews.keyAt(position);
        } else if (isFooterViewPos(position)) {
            return mFootViews.keyAt(position - getHeadersCount() - getRealItemCount());
        }
        return mInnerAdapter.getItemViewType(position - getHeadersCount());
    }

    private int getRealItemCount() {
        return mInnerAdapter.getItemCount();
    }

    @Override
    public int getItemCount() {
        return getHeadersCount() + getFootersCount() + getRealItemCount();
    }


    private boolean isHeaderViewPos(int position) {
        return position < getHeadersCount();
    }

    private boolean isFooterViewPos(int position) {
        return position >= getHeadersCount() + getRealItemCount();
    }

    //add Headers 不重复添加头布局:
    public void addHeaderView(View view) {
        int i = mHeaderViews.indexOfValue(view);
        if (M_DEFAULT_NUMBER == i) {
            mHeaderViews.put(mHeaderViews.size() + BASE_ITEM_TYPE_HEADER, view);
        }
    }

    public void addFootView(View view) {
        int i = mFootViews.indexOfValue(view);
        if (M_DEFAULT_NUMBER == i) {
            mFootViews.put(mFootViews.size() + BASE_ITEM_TYPE_FOOTER, view);
        }
    }

    public int getHeadersCount() {
        return mHeaderViews.size();
    }

    public int getFootersCount() {
        return mFootViews.size();
    }

    //针对网格布局:
    @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
        mInnerAdapter.onAttachedToRecyclerView(recyclerView);
        final RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
        if (manager instanceof GridLayoutManager) {
            ((GridLayoutManager) manager).setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
                @Override
                public int getSpanSize(int position) {
                    //如果是头布局或者是脚布局返回为1;
                    int itemViewType = getItemViewType(position);
                    if (mHeaderViews.get(itemViewType) != null || mFootViews.get(itemViewType) != null) {
                        return ((GridLayoutManager) manager).getSpanCount();
                    }
                    return 1;
                }
            });
        }
    }

    //针对流式布局
    @Override
    public void onViewAttachedToWindow(BaseViewHolder holder) {
        mInnerAdapter.onViewAttachedToWindow(holder);
        int layoutPosition = holder.getLayoutPosition();
        if (isHeaderViewPos(layoutPosition) || isFooterViewPos(layoutPosition)) {
            ViewGroup.LayoutParams layoutParams = holder.itemView.getLayoutParams();
            if (layoutParams != null) {
                if (layoutParams instanceof StaggeredGridLayoutManager.LayoutParams) {
                    StaggeredGridLayoutManager.LayoutParams params = (StaggeredGridLayoutManager.LayoutParams) layoutParams;
                    //占领全部空间;
                    params.setFullSpan(true);
                }
            }
        }
    }

    //remover header;
    public boolean removedHeader(View view) {
        int i = mHeaderViews.indexOfValue(view);
        if (i == M_DEFAULT_NUMBER ) {
            return false;
        }
        mHeaderViews.removeAt(i);
        notifyItemRemoved(i);
        return true;
    }

    //remover footer
    public boolean removedFooter(View view) {
        int i = mFootViews.indexOfValue(view);
        if (i == M_DEFAULT_NUMBER ) {
            return false;
        }
        mFootViews.removeAt(i);
        notifyItemRemoved(i);
        return true;
    }

    //remover all footerview;
    public boolean removerAllFooterView() {
        if (mFootViews.size() > 0) {
            mFootViews.clear();
            notifyDataSetChanged();
            return true;
        }
        return false;
    }

    //remover all footerview;
    public boolean removerAllHeaderView() {
        if (mHeaderViews.size() > 0) {
            mHeaderViews.clear();
            notifyDataSetChanged();
            return true;
        }
        return false;
    }


}

在Activity里面直接这样使用

• 添加头

ComAdapter   comAdapter = new ComAdapter(C.getList());
        View view = mInflate.inflate(R.layout.header_view, (ViewGroup) mRecyView.getParent(), false);
        HeaderAndFooterWrapper<String> emptyViewAdapter = new HeaderAndFooterWrapper<String>(comAdapter);
        emptyViewAdapter.addHeaderView(view);
        emptyViewAdapter.addFootView(view);
        mRecyView.setAdapter(emptyViewAdapter);
///new HeaderAndFooterWrapper() 将当前的comAdapter 传入进去, 可以添加多个头布局和脚布局: 

• 移移除单个头布局和单个脚布局
• removedHeader
• removedFooter
• 移除所有的头布局和脚布局
• removerAllHeaderView
• removerAllFooterView

总结:

终于写完了,是不是感觉用起来很简单,像之前的ListView 一样的 直接可以添加头,移除头 添加脚布局,移除脚布局;由于时间有限没有录gif视屏,后期一定补上, 废话也就不多说了,如果大家觉得我写的还不错,就抬起手给点个赞呗,如果有更好的或者觉得写的有问题的欢迎提问和骚扰
谢谢大家;