java - 设置空适配器-FirestoreRecyclerAdapter
问题描述
E/RecyclerView: No adapter attached; skipping layout在片段内使用 FirestoreRecylerAdapter 时出现错误。在阅读了类似问题的所有答案后，我无法找到解决方案，因为它们中的大多数都是针对 activiy 中的 recylerAdapter 的，即他们有一个 onCreate 方法，可以在其中首先设置他们的适配器。如您所知，在片段中，onCreate 方法中没有视图，因此我在那里找不到我的 recyclerView。一些答案建议设置一个空适配器，然后通知数据更改。我无法在 onCreateView 中设置一个空适配器。这是我的代码：
我的适配器：
package com.example.XX;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.firebase.ui.firestore.FirestoreRecyclerAdapter;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;
public class ProfileRecyclerAdapter extends FirestoreRecyclerAdapter<Profile,ProfileRecyclerAdapter.ProfileViewHolder> {
public ProfileRecyclerAdapter(@NonNull FirestoreRecyclerOptions<Profile> options) {
super(options);
}
@Override
protected void onBindViewHolder(@NonNull ProfileViewHolder holder, int position, @NonNull Profile profile) {
holder.Name_textView.setText(profile.getName());
holder.Sector_textView.setText(profile.getSector());
holder.Pincode_textView.setText(profile.getPincode());
}
@NonNull
@Override
public ProfileViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
LayoutInflater layoutInflater=LayoutInflater.from(parent.getContext());
View view=layoutInflater.inflate(R.layout.profile_row_item,parent,false);
return new ProfileViewHolder(view);
}
class ProfileViewHolder extends RecyclerView.ViewHolder{
TextView Name_textView;
TextView Sector_textView;
TextView Pincode_textView;
public ProfileViewHolder(@NonNull View itemView) {
super(itemView);
Name_textView=itemView.findViewById(R.id.Name_textView);
Sector_textView=itemView.findViewById(R.id.Sector_textView);
Pincode_textView=itemView.findViewById(R.id.Pincode_textView);
}
}
}
我希望显示数据的片段：
package com.example.XX;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
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.firebase.ui.firestore.FirestoreRecyclerOptions;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.android.gms.tasks.Tasks;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.firestore.DocumentReference;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;
import com.google.firebase.firestore.QueryDocumentSnapshot;
import com.google.firebase.firestore.QuerySnapshot;
import java.util.List;
public class MainQueryFragment extends Fragment {
RecyclerView recyclerView;
ProfileRecyclerAdapter profileRecyclerAdapter;
TextView yourSector;
TextView yourPincode;
FirebaseFirestore db = FirebaseFirestore.getInstance();
String tuserID = FirebaseAuth.getInstance().getCurrentUser().getUid();
String customerPincode;
String customerSector;
String sectorText;
String pincodeText;
String[] testArray;
String name;
String pincode;
String address;
String mobileNumber;
String sector;
String avgDeliveryTime;
String avgDeliveryTimeUrg;
Boolean item1;
Boolean item2;
Boolean item3;
Boolean item4;
Boolean item5;
Boolean item6;
Boolean item7;
Boolean item8;
Boolean item9;
Boolean item10;
String speciality;
String avgNumOrders;
String shopType;
String userID;
String avgPriceRange;
String education;
Button button;
public MainQueryFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_main_query, container, false);
yourSector = view.findViewById(R.id.Sector_tv);
yourPincode = view.findViewById(R.id.Pincode_tv);
recyclerView = view.findViewById(R.id.recyclerView_Profile);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(profileRecyclerAdapter);
{ DocumentReference docRef = db.collection("customerUsers").document(tuserID);
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
customerPincode = document.getString("pincode");
customerSector = document.getString("sector");
sectorText = "Sector : " + customerSector;
pincodeText = "Pincode : " + customerPincode;
yourSector.setText(sectorText);
yourPincode.setText(pincodeText);
Log.d("work", "onComplete: " + customerPincode);
} else {
Log.d("docref", "No such document");
}
} else {
Log.d("docref", "get failed with ", task.getException());
}
}
});
}//doc for sector,pincode loading
if (getArguments() != null) {
MainQueryFragmentArgs args = MainQueryFragmentArgs.fromBundle(getArguments());
testArray = args.getArrayCheckboxData();
}
return view;
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
button=view.findViewById(R.id.startQuery_button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Query query = FirebaseFirestore.getInstance()
.collection("tUsers")
.whereEqualTo("pincode", customerPincode)
.whereEqualTo("sector", customerSector)
.whereEqualTo(testArray[0], true)
.whereEqualTo(testArray[1], true)
.whereEqualTo(testArray[2], true)
.whereEqualTo(testArray[3], true);
FirestoreRecyclerOptions<Profile> options = new FirestoreRecyclerOptions.Builder<Profile>()
.setQuery(query,Profile.class)
.build();
profileRecyclerAdapter = new ProfileRecyclerAdapter(options);
recyclerView.setAdapter(profileRecyclerAdapter);
profileRecyclerAdapter.startListening();
}
});
}
}
即使我注释掉我的按钮和 onclicklistener 然后运行应用程序，我应该在技术上运行一个空适配器。我仍然遇到同样的错误。请建议我应该做什么，记住我不能使用 onCreate
编辑这是我编辑的代码。现在我得到空指针异常并且我的应用程序崩溃了：
package com.example.XX;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
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.firebase.ui.firestore.FirestoreRecyclerOptions;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import com.google.android.gms.tasks.Tasks;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.firestore.DocumentReference;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;
import com.google.firebase.firestore.QueryDocumentSnapshot;
import com.google.firebase.firestore.QuerySnapshot;
import java.util.List;
public class MainQueryFragment extends Fragment {
RecyclerView recyclerView;
ProfileRecyclerAdapter profileRecyclerAdapter;
TextView yourSector;
TextView yourPincode;
FirebaseFirestore db = FirebaseFirestore.getInstance();
String tuserID = FirebaseAuth.getInstance().getCurrentUser().getUid();
String customerPincode;
String customerSector;
String sectorText;
String pincodeText;
String[] testArray;
String name;
String pincode;
String address;
String mobileNumber;
String sector;
String avgDeliveryTime;
String avgDeliveryTimeUrg;
Boolean item1;
Boolean item2;
Boolean item3;
Boolean item4;
Boolean item5;
Boolean item6;
Boolean item7;
Boolean item8;
Boolean item9;
Boolean item10;
String speciality;
String avgNumOrders;
String shopType;
String userID;
String avgPriceRange;
String education;
Button button;
public MainQueryFragment() {
// Required empty public constructor
}
@Override
public void onStart() {
super.onStart();
profileRecyclerAdapter.startListening();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_main_query, container, false);
yourSector = view.findViewById(R.id.Sector_tv);
yourPincode = view.findViewById(R.id.Pincode_tv);
{ DocumentReference docRef = db.collection("customerUsers").document(tuserID);
docRef.get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
@Override
public void onComplete(@NonNull Task<DocumentSnapshot> task) {
if (task.isSuccessful()) {
DocumentSnapshot document = task.getResult();
if (document.exists()) {
customerPincode = document.getString("pincode");
customerSector = document.getString("sector");
sectorText = "Sector : " + customerSector;
pincodeText = "Pincode : " + customerPincode;
yourSector.setText(sectorText);
yourPincode.setText(pincodeText);
Log.d("work", "onComplete: " + customerPincode);
} else {
Log.d("docref", "No such document");
}
} else {
Log.d("docref", "get failed with ", task.getException());
}
}
});
}//doc for sector,pincode loading
if (getArguments() != null) {
MainQueryFragmentArgs args = MainQueryFragmentArgs.fromBundle(getArguments());
testArray = args.getArrayCheckboxData();
}
return view;
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
button=view.findViewById(R.id.startQuery_button);
recyclerView = view.findViewById(R.id.recyclerView_Profile);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Query query = FirebaseFirestore.getInstance()
.collection("tUsers")
.whereEqualTo("pincode", customerPincode)
.whereEqualTo("sector", customerSector)
.whereEqualTo(testArray[0], true)
.whereEqualTo(testArray[1], true)
.whereEqualTo(testArray[2], true)
.whereEqualTo(testArray[3], true);
FirestoreRecyclerOptions<Profile> options = new FirestoreRecyclerOptions.Builder<Profile>()
.setQuery(query,Profile.class)
.build();
profileRecyclerAdapter = new ProfileRecyclerAdapter(options);
recyclerView.setAdapter(profileRecyclerAdapter);
pailorProfileRecyclerAdapter.notifyDataSetChanged();
}
});
}
@Override
public void onStop() {
super.onStop();
profileRecyclerAdapter.stopListening();
}
}
解决方案
当您第一次在 中创建适配器时onCreateView()，您并没有初始化该适配器，而是直接从属性设置适配器：
ProfileRecyclerAdapter profileRecyclerAdapter;
recyclerView.setAdapter(profileRecyclerAdapter);
您需要初始化您的适配器以将该适配器设置为您的 RecyclerView。
其次，你不应该在你的内部有那个异步调用onCreateView()，而是onViewCreated()在你的视图被创建之后用来处理你的异步调用。
然后，您还将在您的适配器中创建适配器实例onViewCreated()：
FirestoreRecyclerOptions<Profile> options = new FirestoreRecyclerOptions.Builder<Profile>()
.setQuery(query,Profile.class)
.build();
profileRecyclerAdapter = new ProfileRecyclerAdapter(options);
recyclerView.setAdapter(profileRecyclerAdapter);
profileRecyclerAdapter.startListening();
你应该这样做：
profileRecyclerAdapter.startListening();
在你的onStart()和profileRecyclerAdapter.stopListening();你的onStop()
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