Android recyclerview 将参数传递给同一活动中的另一个片段

Question

我已经实现了 recyclerview 并且工作正常，但是当我想通过 Bundle 将 recyclerview 的单击行上的参数传递给同一活动中的另一个片段时 此行有语法错误：

 getActivity().getSupportFragmentManager().beginTransaction().replace(R.id.fragmentsContainer, f ).commit();

getActivity 显示语法错误

//适配器的完整代码：

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;
import com.example.miniprojetandroid.ui.fragments.DetailsFragment;


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);
    }

}

//我的目标片段

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 android.widget.Button;
import android.widget.TextView;

import com.example.miniprojetandroid.R;
import com.example.miniprojetandroid.models.Bike;


public class DetailsFragment extends Fragment {

    Button btnRent, btnFav;
    TextView bike_id,model,type,price;

    public DetailsFragment() {
        // Required empty public constructor
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {

        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_details, container, false);
        btnRent = v.findViewById(R.id.btnRent);
        btnFav = v.findViewById(R.id.btnFav);
        bike_id = v.findViewById(R.id.bike_id);
        model = v.findViewById(R.id.model);
        type = v.findViewById(R.id.type);
        price = v.findViewById(R.id.price);

        int id = getArguments().getInt("id");
        String model = getArguments().getString("model");
        String type = getArguments().getString("type");
        String price = getArguments().getString("price");
        int image = getArguments().getInt("image");
        Bike bike = new Bike(id,model,type,price,image);
        Log.e("ddddddddd",bike.toString());

        return v;
    }


}

在DetailsFragment中编辑什么来获取选中项的数据？

//我的回收站查看Fragment

    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 = new BikesAdapter(getActivity(), (ArrayList<Bike>) bikes);
        recyclerView.setAdapter(mAdapter);
        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());


                    //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) {
        // your codes implementation goes here
        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();
    }




}

在所有的 sugests 之后我像这样编辑了所有内容，但现在 recyclerview 变空了，很明显，使用 Log.e 方法 fillData() 方法显示数据较晚，而 recyclerview 没有足够早地捕获它

Answer 1

（选项 1）您可以在像这样实例化时在适配器中传递您的活动：

public BikesAdapter(Activity mActivity, Context mContext, ArrayList<Bike> bikes) {
        this.mActivity = mActivity ;
        this.mContext = mContext ;
        this.bikes = bikes;
        }

你甚至可以这样做（你可以从你的活动中获取你的上下文）：

public BikesAdapter(Activity mActivity, ArrayList<Bike> bikes) {
        this.mActivity = mActivity ;
        this.mContext = mActivity ;
        this.bikes = bikes;
        }

（选项 2）或简单地为您的适配器内的 onClickListeners 编写接口回调，并在活动内调用它们以实现适配器。效果更好，更完美。下面是一个示例：

public class BikesAdapter  extends RecyclerView.Adapter<BikesAdapter.BikesViewHolder> {
    private Callback mCallback;
    private final ArrayList<Bike> bikes;
    private Context mContext;
    public BikesAdapter(Context mContext, ArrayList<Bike> bikes) {
        this.mContext = mContext ;
        this.bikes = bikes;
    }

    @Override
    public void onBindViewHolder(@NonNull BikesAdapter.BikesViewHolder holder, int position) {
    final Bike singleItem = bikes.get(position);
    holder.bikeView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {   
         mCallback.onItemClicked(singleItem));
    });
    ...

    public void setCallback(Callback callback) {
        mCallback = callback;
    }

    public interface Callback {
        void onItemClicked(Bike bike);
    }
}

在您实现适配器的活动（片段）中，您实现接口并设置回调，就像这样并覆盖方法：

public class FragmentOne extends Fragment implements BikesAdapter.Callback {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.fragment_one, container,false);
        mAdapter = new BikesAdapter(getActivity(), (ArrayList<Bike>) bikes);
        mAdapter.setCallback(this);
    }

    @Override
    public void onItemClicked(Bike bike) {
        // your codes implementation goes here
    getActivity().getSupportFragmentManager()
        .beginTransaction()
        .replace(R.id.fragmentsContainer, f )
        .commit();
    }

}

-------------------以下更新-------------- ------------------

对您的片段进行这些更改。 更新：

• 在适配器定义下采用fillData();方法并
• 在 API 响应中添加 adapter.notifyDataSetChanged();，以便您的适配器收到从 API 获取的新项目中的数据更改的通知。

@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);
        
        mAdapter = new BikesAdapter(getActivity(), (ArrayList<Bike>) bikes);
        recyclerView.setAdapter(mAdapter);
        mAdapter.setCallback(this);
        fillData();


        return rootView;
    }

（选项 1）在 API 响应中添加 adapter.notifyDataSetChanged();。

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());

                    adapter.notifyDataSetChanged();
                   
                }
            }
            @Override
            public void onFailure(Call<List<Bike>> call, Throwable t) {
                Log.e("ERROR: ", t.getMessage());
            }
        });
    }

（选项 2）在适配器中定义一个方法

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;
import com.example.miniprojetandroid.ui.fragments.DetailsFragment;


public class BikesAdapter  extends RecyclerView.Adapter<BikesAdapter.BikesViewHolder> {
    
   .......

   public void addItems(ArrayList<Bike> bikeList) {
        this.bikes = bikeList;
        notifyDataSetChanged();        
    }

     
}

然后只需在您的 API 响应中调用此方法，而不是像这样调用 notifyDataSetChanged();

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());

                    adapter.addItems(bikes);
                   
                }
            }
            @Override
            public void onFailure(Call<List<Bike>> call, Throwable t) {
                Log.e("ERROR: ", t.getMessage());
            }
        });
    }

无论哪种方式，您都可以通过 API 通知适配器新项目。并且您可以再次显示您的列表。

问题

在DetailsFragment中编辑什么来获取选中项的数据？

有两种方法。

（选项1）根据您的实现，只需在DetailsFragment 的onCreate 内的新片段中提取参数，如下所示。

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            Bundle args = getArguments();
            args.getInt("bike_id", null);
            args.getString("model", null);
            args.getString("type", null);
            args.getString("price", null);
            args.getInt("image", null);
        }
    }

（选项 2）或简单地定义一个静态方法，通过简单地传递数据来实例化您的片段，如下所示。简单定义here

private static Bike bike;

public static DetailsFragment newInstance(Bike bikeArg) {
    bike = bikeArg;
    return new DetailsFragment();
}

添加片段实例时，您可以这样操作

@Override
    public void onItemClicked(Bike bike) {
        getActivity().getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.fragmentsContainer, 
                  DetailsFragment.newInstance(Bike bike))
                .commit();
    }

然后您可以从新的DetailFragment 上的bike 变量中获取所有数据。希望一切顺利。

Answer 2

您不能在回收器视图适配器中使用 getSupportFragmentManager。

像这样编辑您的适配器类和容器活动

适配器类

public class BikesAdapter extends RecyclerView.Adapter<BikesAdapter.BikesViewHolder> {
private final ArrayList<Bike> bikes;
private Context mContext;
private OnItemClickListener listener;

public BikesAdapter(ArrayList<Bike> bikes, Context mContext, OnItemClickListener listener) {
    this.bikes = bikes;
    this.mContext = mContext;
    this.listener = listener;
}

@NonNull
@Override
public BikesViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View mItemView = LayoutInflater.from(mContext).inflate(R.layout.bike_list_item, parent, false);
    return new BikesViewHolder(mItemView);
}


@Override
public void onBindViewHolder(@NonNull BikesViewHolder holder, int position) {
    final Bike singleItem = bikes.get(position);

    holder.BikeName.setText(singleItem.getModel());
    holder.BikeImage.setBackgroundResource(singleItem.getImage());
}

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


public class BikesViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
    TextView BikeName;
    ImageView BikeImage;
    Button bikeView;
    WeakReference<OnItemClickListener> listenerReference;

    public BikesViewHolder(@NonNull View itemView) {
        super(itemView);
        BikeName = itemView.findViewById(R.id.bikeName);
        BikeImage = itemView.findViewById(R.id.bikeImage);
        bikeView = itemView.findViewById(R.id.btn_view);

        listenerReference = new WeakReference<>(listener);

        bikeView.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        if (v == bikeView){
            listenerReference.get().onClick(bikes.get(getAdapterPosition()));
        }
    }
}

public interface OnItemClickListener {
    void onClick(Bike bike);
}

}

然后你应该在你的容器活动中调用这个适配器，如下所示

BikesAdapter adapter = new BikesAdapter(bikeArrayList, this, new BikesAdapter.OnItemClickListener() {
        @Override
        public void onClick(Bike bike) {
            Bundle bundle = new Bundle();
            bundle.putInt("bikeId", bike.getId());
            /*
            .
            .
            .
            Do your stuff here with getSupportFragmentManager()
             */
        }
    });

然后将此适配器对象设置为您的回收站视图