Android开发笔记（二十六）底部加载更多

用viewType的方法做区分

1. 制作加载条layout，改progressbar颜色如下，需要API21以上
1. adpater重写区分viewtype

    static final int VIEW_TIPE_NORMAL = 0;
    static final int VIEW_TIPE_BOTTOM = 1;
    @Override
    public int getItemCount() {
        return super.getItemCount() + 1;
    }

    @Override
    public int getItemViewType(int position) {
        return position == getItemCount() - 1 ? VIEW_TIPE_BOTTOM : VIEW_TIPE_NORMAL;
    }

3 adpater中修改onCreateViewHolder

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull final ViewGroup parent, int viewType) {
        final MyViewHolder myViewHolder;
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        if (viewType == VIEW_TIPE_NORMAL){
            // 原来的myViewHolder创建方法
        }else {
            final View itemView = inflater.inflate(R.layout.footer, parent, false);
            myViewHolder = new MyViewHolder(itemView);
        }
        return myViewHolder;
    }

4 onBindViewHolder添加：

    @Override
    public void onBindViewHolder(@NonNull final MyViewHolder holder, int position) {
        if (getItemCount() - 1 == position) {
            return;
        }
}

1. 监听加载：（还有很多相似方法，这里就列举一个）

        recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
                super.onScrollStateChanged(recyclerView, newState);
            }

            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                super.onScrolled(recyclerView, dx, dy);
                if (dy < 0 ){return;}
                GridLayoutManager layoutManager = (GridLayoutManager) recyclerView.getLayoutManager();
                int p = layoutManager.findLastVisibleItemPosition();
                if (p == myAdapter.getItemCount() - 1){
                    Log.i("test","到底了");
                  //加载功能性代码
                }
            }
        });

加载记得做判断防止多次连续请求