Question

我想使用Marvel API和Retrofit制作一个应用程序。收到响应后，它只会向我显示前10或20个结果，这是API的基本限制。如何滚动到屏幕底部，以便加载更多数据？

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private MyAdapter myAdapter;
    private RecyclerView myRecyclerView;

    private RequestManager glide;

    Date today = new Date();
    int ts = 1;

    private static final String API_KEY = "c05b97de2b2e597428a65451d0df12a7";
    private static final String HASH = "9e36e240cadffa03ecaa206887b23335";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        this.glide = glide;

//Create a handler for the RetrofitInstance interface//

        GetData service = RetrofitClient.getRetrofitInstance().create(GetData.class);

        Call<MarvelResponse> call = service.getAllCharacters(Long.valueOf(ts), API_KEY, HASH);

        call.enqueue(new Callback<MarvelResponse>() {

            @Override

//Handle a successful response//

            public void onResponse(Call<MarvelResponse> call, Response<MarvelResponse> response) {
                loadDataList(response.body());
            }

            @Override

//Handle execution failures//

            public void onFailure(Call<MarvelResponse> call, Throwable throwable) {

//If the request fails, then display the following toast//

                Toast.makeText(MainActivity.this, "Unable to load users", Toast.LENGTH_SHORT).show();
            }
        });

    }

//Display the retrieved data as a list//

    private void loadDataList(MarvelResponse usersList) {

//Get a reference to the RecyclerView//

        myRecyclerView = findViewById(R.id.myRecyclerView);
        myAdapter = new MyAdapter(usersList.getData().getResults());

//Use a LinearLayoutManager with default vertical orientation//

        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
        myRecyclerView.setLayoutManager(layoutManager);

//Set the Adapter to the RecyclerView//

        myRecyclerView.setAdapter(myAdapter);
    }

}

MyAdapter.java

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.CustomViewHolder> {

    private static final String TAG = MyAdapter.class.getSimpleName();
    private List<MarvelResults> dataList;

    public MyAdapter(List<MarvelResults> dataList){
        this.dataList=dataList;
    }

    class CustomViewHolder extends RecyclerView.ViewHolder{
        //get a reference to the Views in our layout
        public final View myView;

        TextView textCharacter;
        TextView textDescription;
        ImageView imageView;
        LinearLayout linearLayout;

        CustomViewHolder(View itemView){
            super(itemView);
            myView = itemView;

            textCharacter = myView.findViewById(R.id.character);
            textDescription = myView.findViewById(R.id.description);
            imageView = myView.findViewById(R.id.imageView);

        }
    }

    //construct a RecyclerView.ViewHolder
    public CustomViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
        View view = layoutInflater.inflate(R.layout.row_layout, parent, false);
        return new CustomViewHolder(view);
    }

    @Override

    //set the data

    public void onBindViewHolder(CustomViewHolder holder, int position) {

        holder.textCharacter.setText(dataList.get(position).getName());
        holder.textDescription.setText(dataList.get(position).getDescription());

        Uri uri = Uri.parse(dataList.get(position).getThumbnail());
        Glide.with(holder.imageView.getContext()).load(uri).into(holder.imageView);
        Log.d(TAG, "onBindViewHolder() called with: holder = [" + uri + "], position = [" + position + "]");

    }

    //calculate the item count for the RecylerView//

    @Override
    public int getItemCount() {
        return dataList.size();
    }

}

对不起，我是初学者。

谢谢！

这是Marvel Api文档的link。

Answer 1

我认为您需要在请求中使用offset和limit参数。例如，您可以在每个请求中将offset增加20，并在limit 0处设置offset在20上，并在每次到达底部时将其增加。因此，每个请求都应返回下20个项目。在这里看看：https://developer.marvel.com/documentation/apiresults

要检测何时RecyclerView到达底部，可以使用addOnScrollListener这样的东西：

private int firstVisibleItem, visibleItemCount, totalItemCount;
private boolean loading = true;
private int offset = 0;

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);

            visibleItemCount = recyclerView.getChildCount();
            totalItemCount = layoutManager.getItemCount();
            firstVisibleItem = layoutManager.findFirstVisibleItemPosition();

             if (loading) {
                if (totalItemCount > previousTotal) {
                    loading = false;
                    previousTotal = totalItemCount;
                }
            }
            if (!loading && (visibleItemCount + firstVisibleItem)
                    >= totalItemCount) {
                // End has been reached

                offset += 20;
                // send request to load more videos here

                loading = true;
            }
        }

    });

（Android）在我滚动到屏幕底部时将数据加载到RecyclerView

1 个答案: