Android RecyclerView 添加分页

Question

我为我的应用程序创建了一个 RecyclerView 并试图找到一种方法来停止大量请求，我想获得 10 x 10 的结果并带有进度条。我的服务器将在每次向下滚动到最后一项时发送 10 x 10 的结果。

    public class ProfileActivityFriendsList extends AppCompatActivity {
        String[] names={"Ander Herera","David De Gea","Michael Carrick","Juan Mata","Diego Costa","Oscar"};
        String[] positions={"Midfielder","GoalKeeper", "Midfielder","Playmaker","Striker","Playmaker"};
        String[] urls={"Midfielder","GoalKeeper", "Midfielder","Playmaker","Striker","Playmaker"};
        int[] images = {R.mipmap.ic_launcher,R.mipmap.ic_launcher, R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher,R.mipmap.ic_launcher};

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_profile_friends_list);

            Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
            setSupportActionBar(toolbar);

            //GET RECYCLER
            RecyclerView rv = (RecyclerView) findViewById(R.id.myRecycler);
            //SET LAYOUT
            rv.setLayoutManager(new LinearLayoutManager(this));
            rv.setItemAnimator(new DefaultItemAnimator());
            //ADAPTER
            MyAdapter adapter = new MyAdapter(this, names, positions, urls, images);
            rv.setAdapter(adapter);
        }
} 

这是我的适配器类。

public class MyAdapter extends RecyclerView.Adapter<MyHolder> {
    Context c;
    String[] names;
    String[] positions;
    String[] urls;
    int[] img;

    public MyAdapter(Context ctx, String[] names, String[] positions,String[] urls, int[] images){
        this.c=ctx;
        this.names = names;
        this.positions = positions;
        this.img = images;
        this.urls = urls;
    }
    @Override
    public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.friend_list_model,null);

        MyHolder holder = new MyHolder(v);
        return holder;
    }

    @Override
    public void onBindViewHolder(MyHolder holder, final int position) {
        holder.imageView.setImageResource(img[position]);
        holder.name.setText(names[position]);
        holder.desc.setText(positions[position]);

        holder.serItemClickListener(new ItemClickListener() {
            @Override
            public void onItemClick(View v, int pos) {
                Snackbar.make(v,positions[position]+" "+positions[position],Snackbar.LENGTH_LONG).show();
            }
        });
    }

    @Override
    public int getItemCount() {
        return names.length;
    }
}

这是持有人。

public class MyHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
    CircleImageView imageView;
    TextView name;
    TextView desc;
    ItemClickListener itemClickListener;
    public MyHolder(View itemView) {
        super(itemView);

        imageView = (CircleImageView) itemView.findViewById(R.id.circleImageView1);
        name = (TextView) itemView.findViewById(R.id.textName);
        desc = (TextView) itemView.findViewById(R.id.textDesc);
        itemView.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        this.itemClickListener.onItemClick(v,getLayoutPosition());
    }
    public void serItemClickListener(ItemClickListener ic){
        this.itemClickListener = ic;
    }
}

我看了很多教程，但找不到明确的解决方案，我认为有一些方法可以做到，但我不知道我的代码是否可以添加它？

Answer 1

我们所做的是使用 ReyclerView.OnScrollListener .假设您使用的是 LinearLayoutManager，您可以检查当前显示的项目与总数以确定何时到达最后一个项目，然后请求下一页。您还需要进行一些额外的逻辑检查以提前结束以防止“垃圾邮件”，因为滚动甚至会发生很多次。

例如:

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
        if (!hasMoreContent()) {
            return;
        }

        if (currentlyLoadingInitialRequest()) {
            return;
        }

        if (alreadyLoadingNextPage()) {
            return;
        }

        if (isInErrorState()) {
            return;
        }

        LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
        int total = layoutManager.getItemCount();
        int currentLastItem = layoutManger.findLastVisibleItemPosition();
        if (currentLastItem == total - 1) {
            requestNextPage();
        }
    });