我收到了来自 api 的单件商品

Question

我试图在 RecyclerView 中显示来自 API 响应的温度值。事情是我的程序不断地只显示一个，第一个项目。我不确定问题出在哪里，我觉得有点迷茫。

我要显示的 api 响应的一部分

"hourly": [
{
  "dt": 1607184000,
  "temp": x,
  "feels_like": x,
  "pressure": x,
  "humidity": x,
  "dew_point": x,
  "uvi": x,
  "clouds": x,
  "visibility": x,
  "wind_speed": x,
  "wind_deg": x,
  "pop": x
},
and so on...

型号class

public class ForecastModel {
@SerializedName("hourly")
private List<HourlyForecast> hourlyForecast = null;

public List<HourlyForecast> getHourlyForecast() {
    return hourlyForecast;
}
public class HourlyForecast{
    @SerializedName("dt")
    private int dt;

    public int getDt() {
        return dt;
    }
}

}

Activity class

    public class HourlyForecastActivity extends AppCompatActivity {
    private static final String TAG = "HourlyForecastActivity";
    private List<ForecastModel> mData = new ArrayList<>();
    RecyclerView recyclerView;
    HourlyForecastAdapter adapter;

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

        recyclerView = findViewById(R.id.hourly_recycler_view);
        adapter = new HourlyForecastAdapter();

        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setHasFixedSize(true);
        recyclerView.setAdapter(adapter);
        prepareConnection();
    }
   private void prepareConnection(){
        ForecastViewModel viewModel = new ViewModelProvider(this).get(ForecastViewModel.class);
        viewModel.getData().observe(this, new Observer<ForecastModel>() {
            @Override
            public void onChanged(ForecastModel forecast) {
                if (mData.size() > 0){
                    mData.clear();
                }
                if (forecast != null){
                    mData.addAll(Collections.singleton(forecast));
                    adapter.setData(mData);
                }
            }
        });
   }
}

适配器class

    public class HourlyForecastAdapter extends RecyclerView.Adapter<HourlyForecastAdapter.HourlyViewHolder> {
    private List<ForecastModel> mHourlyData = new ArrayList<>();

    public void setData(List<ForecastModel> mHourlyData){
        this.mHourlyData = mHourlyData;
        notifyDataSetChanged();
    }

    @NonNull
    @Override
    public HourlyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.hourly_items, parent, false);
        return new HourlyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull HourlyViewHolder holder, int position) {
        ForecastModel model = mHourlyData.get(position);
        holder.mTemperature.setText(String.valueOf(model.getHourlyForecast().get(position).getDt()));

    }

    @Override
    public int getItemCount() {
        return mHourlyData.size();
    }

    public class HourlyViewHolder extends RecyclerView.ViewHolder {
        private TextView mTemperature, mPressure, mHumidity, mWindSpeed, mDescription;
        private ImageView mIcon;

        public HourlyViewHolder(@NonNull View itemView) {
            super(itemView);

            mTemperature = itemView.findViewById(R.id.hourly_temperature);
            mPressure = itemView.findViewById(R.id.hourly_pressure);
            mHumidity = itemView.findViewById(R.id.hourly_humidity);
            mWindSpeed = itemView.findViewById(R.id.hourly_wind_speed);
            mDescription = itemView.findViewById(R.id.hourly_description);
        }
    }
}

Answer 1

适配器中的 setData 方法有点误导（命名和变量方面）。查看 Activity 中的 onChanged 方法：您正在使用的是单个 ForecastModel 对象。将该对象作为名为 mHourlyData 的 List 传递给 setData 中的适配器是导致最初混淆的原因。 List 的大小将始终为 1，从而导致您面临的问题。

我建议更改 onChanged 方法调用以简单地执行此操作：

adapter.setData(forecast)

并重命名 setData 中的适配器变量以反映您实际接收（想要接收）的内容：

private List<HourlyForecast> mHourlyForecast = new ArrayList<>();

public void setData(ForecastModel forecast){
    this.mHourlyForecast = forecast.hourlyForecast;
    notifyDataSetChanged();
}

在那之后，唯一剩下要做的就是相应地更新您的 getItemCount 和 onBindViewHolder 方法。

我收到了来自 api 的单件商品

I've received single item from api

java

android

mvvm

retrofit