不得附加 ViewHolder 视图

Question

我是android编程的新手。我有一个可以插入到云 Firestore 中的应用程序，它还需要读取 Cloud Firestore 中的数据。当我尝试打开读取数据的活动时，它一直崩溃。logcat 给出了这个错误

2021-01-12 21:20:56.733 25524-25524/com.example.ppw1 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.ppw1, PID: 25524
java.lang.IllegalStateException: ViewHolder views must not be attached when created. Ensure that you are not passing 'true' to the attachToRoot parameter of LayoutInflater.inflate(..., boolean attachToRoot)
    at androidx.recyclerview.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:7080)
    at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6235)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
    at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
    at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
    at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
    at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
    at androidx.recyclerview.widget.RecyclerView.consumePendingUpdateOperations(RecyclerView.java:1897)
    at androidx.recyclerview.widget.RecyclerView$1.run(RecyclerView.java:414)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
    at android.view.Choreographer.doCallbacks(Choreographer.java:683)
    at android.view.Choreographer.doFrame(Choreographer.java:616)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6077)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

我的代码是：

2021-01-12 21:20:56.733 25524-25524/com.example.ppw1 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.ppw1, PID: 25524
java.lang.IllegalStateException: ViewHolder views must not be attached when created. Ensure that you are not passing 'true' to the attachToRoot parameter of LayoutInflater.inflate(..., boolean attachToRoot)
    at androidx.recyclerview.widget.RecyclerView$Adapter.createViewHolder(RecyclerView.java:7080)
    at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6235)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
    at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
    at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
    at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
    at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
    at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
    at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
    at androidx.recyclerview.widget.RecyclerView.consumePendingUpdateOperations(RecyclerView.java:1897)
    at androidx.recyclerview.widget.RecyclerView$1.run(RecyclerView.java:414)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
    at android.view.Choreographer.doCallbacks(Choreographer.java:683)
    at android.view.Choreographer.doFrame(Choreographer.java:616)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
    at android.os.Handler.handleCallback(Handler.java:751)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:154)
    at android.app.ActivityThread.main(ActivityThread.java:6077)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

我的 DoToAdapter 代码正在处理大部分查询，我认为错误必须是这些类之一，但我不确定。

package com.example.ppw1;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.firebase.ui.firestore.FirestoreRecyclerAdapter;
import com.firebase.ui.firestore.FirestoreRecyclerOptions;

import android.os.Bundle;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.firestore.CollectionReference;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.Query;

public class ListActivities extends AppCompatActivity {

    private FirebaseAuth mAuth;
    private FirebaseFirestore db = FirebaseFirestore.getInstance();
    private CollectionReference todoRef = db.collection("users");
    private ToDoAdapter adapter;
    private RecyclerView mFirestoreList;

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

        this.setTitle("List Activity");

        mAuth = FirebaseAuth.getInstance();

        setUpRecyclerView();

        mFirestoreList = findViewById(R.id.firestore_list);
    }

    private void setUpRecyclerView()
    {
        Query query = todoRef.whereEqualTo("Email", mAuth.getCurrentUser().getEmail());

        FirestoreRecyclerOptions<ToDoItem> options = new FirestoreRecyclerOptions.Builder<ToDoItem>().setQuery(query,ToDoItem.class).build();


        adapter = new ToDoAdapter(options);

        RecyclerView recyclerView = findViewById(R.id.firestore_list);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);
    }

    @Override
    protected void onStart()
    {
        super.onStart();
        adapter.startListening();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        adapter.stopListening();
    }
}

Answer 1

java.lang.IllegalStateException：创建时不得附加 ViewHolder 视图。确保您没有将“true”传递给 LayoutInflater.inflate(..., boolean attachToRoot) 的 attachToRoot 参数

attachToRoot如果ViewGroup参数不是，则默认值为真，null请参见2-arg inflate 方法：

public View inflate(@LayoutRes int resource, @Nullable ViewGroup root) {
    return inflate(resource, root, root != null);
}

因此，当您在其中膨胀项目布局时，您需要使用3-arginflate()方法将第三个attachToRoot参数设置为falseonCreateViewHolder()

@NonNull
@Override
public ToDoHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_to_do_item, parent, false);

    return new ToDoHolder(v);
}

attachToRoot膨胀的层次结构是否应该附加到根参数？如果为 false，则 root 仅用于为 XML 中的根视图创建正确的 LayoutParams 子类。