无法解析getcontext（）

Question

package fragment;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.myapplication.R;
import com.example.myapplication.UserAdapter;
import com.example.myapplication.Users;
import com.google.firebase.database.FirebaseDatabase;
import java.util.ArrayList;
public class Chat_frg extends Fragment {
public Chat_frg(){

}
ArrayList<Users> list=new ArrayList<>();
FirebaseDatabase database;
RecyclerView recyclerView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    database=FirebaseDatabase.getInstance();
    recyclerView.findViewById(R.id.chatRecyclerView);
    UserAdapter adapter = new UserAdapter(list.getContext());
    recyclerView.setAdapter(adapter);
    LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
    return inflater.inflate(R.layout.fragment_chat_frg, container, false);
    }
}

package com.example.myapplication;

public class Users {
    String ProfilePic,Name,phoneNumber,Email,password,userId,lastMessage,status;

    public Users(){

    }

    public Users(String profilePic, String name, String phoneNumber, String email, String password, String userId, String lastMessage, String status) {
        ProfilePic = profilePic;
        Name = name;
        this.phoneNumber = phoneNumber;
        Email = email;
        this.password = password;
        this.userId = userId;
        this.lastMessage = lastMessage;
        this.status = status;
    }

    public Users(String name, String email, String password) {
        Name = name;
        Email = email;
        this.password = password;
    }

    public String getProfilePic() {
        return ProfilePic;
    }

    public void setProfilePic(String profilePic) {
        ProfilePic = profilePic;
    }

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }

    public String getEmail() {
        return Email;
    }

    public void setEmail(String email) {
        Email = email;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    public String getLastMessage() {
        return lastMessage;
    }

    public void setLastMessage(String lastMessage) {
        this.lastMessage = lastMessage;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}

Answer 1

老实说，我对这段代码很困惑：

ArrayList<Users> list=new ArrayList<>();
...
UserAdapter adapter = new UserAdapter(list.getContext());

list是ArrayList的一个实例，一般来说，它与上下文无关，但是仍然调用list.getcontext()，似乎是要将上下文传递给类UserAdapter。

如果希望在UserAdpater类中使用上下文，可以传递getactivity()或getcontext()，当然，首先应该在UserAdapter中使用Context Context属性。

class UserAdapter{
    private Context context;
    UserAdapter(Context context) {
        this.context = context;
    }
}

UserAdapter adapter = new UserAdapter(getActivity() or getContext());