【发布时间】：2021-03-14 17:44:50
【问题描述】：
我已经实现了 recyclerview 并且工作正常，我在 BikeAdapter 中使用了回调来能够单击此回收器视图的每一行但是当我将这些行放在 OnCreateView 中时，回收器视图回收器会抛出 null 回调错误，并且当我删除 mAdapter.setCallback(this);回收站视图变空了
recyclerView.setAdapter(mAdapter); fillData();
mAdapter = new BikesAdapter(getActivity(), (ArrayList<Bike>) bikes);
mAdapter.setCallback(this);
当我将这些行放在 filldata() OnResponse 方法中时：无法识别 mAdapter.setCallback(this)
mAdapter.setCallback(this);
如果我想毫无问题地显示我的回收站视图，我必须删除 mAdapter.setCallback(this); mAdapter = new BikesAdapter(getActivity(), (ArrayList) 自行车); recyclerView.setAdapter(mAdapter); 在 fillData 内部以在正确的时间获得响应
//我的适配器代码
package com.example.miniprojetandroid.adapters;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.example.miniprojetandroid.R;
import com.example.miniprojetandroid.models.Bike;
public class BikesAdapter extends RecyclerView.Adapter<BikesAdapter.BikesViewHolder> {
private final ArrayList<Bike> bikes;
private Context mContext;
private Callback mCallback;
public BikesAdapter(Context mContext, ArrayList<Bike> bikes) {
this.mContext = mContext ;
this.bikes = bikes;
}
@NonNull
@Override
public BikesAdapter.BikesViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View mItemView = LayoutInflater.from(mContext).inflate(R.layout.bike_list_item, parent, false);
return new BikesViewHolder(mItemView, this);
}
@Override
public void onBindViewHolder(@NonNull BikesAdapter.BikesViewHolder holder, int position) {
final Bike singleItem = bikes.get(position);
holder.BikeName.setText(singleItem.getModel());
holder.BikeImage.setBackgroundResource(singleItem.getImage());
holder.bikeView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mCallback.onItemClicked(singleItem);
}
});
holder.BikeImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext,singleItem.getModel(),Toast.LENGTH_SHORT).show();
}
});
}
@Override
public int getItemCount() {
return bikes.size();
}
public class BikesViewHolder extends RecyclerView.ViewHolder {
public final TextView BikeName;
public final ImageView BikeImage;
public final Button bikeView;
final BikesAdapter mAdapter;
public BikesViewHolder(@NonNull View itemView, BikesAdapter mAdapter) {
super(itemView);
this.BikeName = itemView.findViewById(R.id.bikeName);
this.BikeImage = itemView.findViewById(R.id.bikeImage);
this.bikeView = itemView.findViewById(R.id.btn_view);
this.mAdapter = mAdapter;
}
}
public void setCallback(Callback callback) {
mCallback = callback;
}
public interface Callback {
void onItemClicked(Bike bike);
}
}
//包含recyclerview的我的片段
package com.example.miniprojetandroid.ui.fragments;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.miniprojetandroid.R;
import java.util.ArrayList;
import java.util.List;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import com.example.miniprojetandroid.Retrofit.BikeService;
import com.example.miniprojetandroid.Retrofit.RetrofitClient;
import com.example.miniprojetandroid.Retrofit.UserService;
import com.example.miniprojetandroid.adapters.BikesAdapter;
import com.example.miniprojetandroid.models.Bike;
import com.example.miniprojetandroid.models.User;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
public class FragmentOne extends Fragment implements BikesAdapter.Callback{
private BikeService apiService;
private RecyclerView recyclerView;
private List<Bike> bikes = new ArrayList<Bike>();
private BikesAdapter mAdapter;
List<Bike> result = new ArrayList<Bike>();
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_one, container,false);
recyclerView = rootView.findViewById(R.id.recycler_bikes);
recyclerView.setHasFixedSize(true);
recyclerView.setNestedScrollingEnabled(true);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity(),
LinearLayoutManager.VERTICAL, false));
apiService = RetrofitClient.getClient().create(BikeService.class);
fillData();
mAdapter.setCallback(this);
return rootView;
}
public void fillData(){
Call<List<Bike>> call = apiService.getBikes();
call.enqueue(new Callback<List<Bike>>() {
@Override
public void onResponse(Call<List<Bike>> call, Response<List<Bike>> response) {
if(response.isSuccessful()){
bikes.addAll(response.body());
for(Bike bike: bikes){
bike.setImage(R.drawable.ruebike);
}
Log.e("Bike LIST", bikes.toString());
mAdapter = new BikesAdapter(getActivity(), (ArrayList<Bike>) bikes);
recyclerView.setAdapter(mAdapter);
//listView.setAdapter(new UserAdapter(MainActivity.this, R.layout.list_user, list));
}
}
@Override
public void onFailure(Call<List<Bike>> call, Throwable t) {
Log.e("ERROR: ", t.getMessage());
}
});
/*bikes.add(new Bike(1,"ECO", "RTT" , "44", R.drawable.ruebike ));
bikes.add(new Bike(2,"AAA", "RTT" , "33", R.drawable.ruebike ));
bikes.add(new Bike(3,"BBB", "RUE" , "11", R.drawable.ruebike ));
bikes.add(new Bike(4,"EEE", "SPORT" , "25", R.drawable.ruebike ));
bikes.add(new Bike(5,"CCC", "SPORT" , "77", R.drawable.ruebike ));
Log.e("USERS LIST", bikes.toString());*/
}
@Override
public void onItemClicked(Bike bike) {
Bundle bundle = new Bundle();
bundle.putInt("bike_id",bike.getId());
bundle.putString("model", bike.getModel());
bundle.putString("type", bike.getType());
bundle.putString("price", bike.getPrice());
bundle.putInt("image", bike.getImage());
DetailsFragment f = new DetailsFragment();
f.setArguments(bundle);
getActivity().getSupportFragmentManager()
.beginTransaction()
.replace(R.id.fragmentsContainer, f )
.commit();
}
}
我想做的是两件事： 1/使用回调方法使我的片段recyclerview与filldata一起使用（对于idea Log.e表明该方法工作正常） 2/ 确保当我点击回收站视图的一个项目时，我将选定的自行车传递给一个 hired fragmend (DetailsFragment)
错误：当我删除回调时回收器视图是空的，当我使用它时它会抛出空异常
请帮帮我
【问题讨论】：
标签： android android-recyclerview retrofit android-adapter