我的 Android 应用程序无法识别我的适配器。没有连接适配器跳过布局

Question

我正在制作一个日记应用程序，每当我尝试使用工具栏上的菜单时，它都会说没有适配器附加跳过布局，并且不允许我将其他日记添加到我的日记列表（回收器视图）中。

package com.example.self;

import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

import androidx.activity.EdgeToEdge;
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.firestore.CollectionReference;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.QueryDocumentSnapshot;
import com.google.firebase.firestore.QuerySnapshot;
import com.google.firebase.storage.StorageReference;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import model.Journal;
import ui.JournalRecyclerAdapter;
import util.JournalApi;

public class JournalListActivity extends AppCompatActivity {
    private FirebaseAuth firebaseAuth;
    private FirebaseAuth.AuthStateListener authStateListener;
    private FirebaseUser user;
    private FirebaseFirestore db = FirebaseFirestore.getInstance();
    private StorageReference storageReference;
    private List<Journal> journalList;
    private RecyclerView recyclerView;
    private JournalRecyclerAdapter journalRecyclerAdapter;

    private CollectionReference collectionReference = db.collection("Journal");
    private TextView noJournalEntry;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_journal_list);
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
            Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
            return insets;
        });

        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        }

        firebaseAuth = FirebaseAuth.getInstance();
        user = firebaseAuth.getCurrentUser();

        noJournalEntry = findViewById(R.id.list_no_thoughts);
        journalList = new ArrayList<>();
        recyclerView = findViewById(R.id.recycleView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(@NonNull MenuItem item) {
        if (item.getItemId() == R.id.action_add) {
            if (user != null && firebaseAuth != null) {
                startActivity(new Intent(JournalListActivity.this, PostJournalActivity.class));
                finish();
            }
        } else if (item.getItemId() == R.id.action_signout) {
            if (user != null && firebaseAuth != null) {
                firebaseAuth.signOut();
                startActivity(new Intent(JournalListActivity.this, MainActivity.class));
                finish();
            }
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onStart() {
        super.onStart();

        collectionReference.whereEqualTo("userId", JournalApi.getInstance()
                        .getUserId())
                .get()
                .addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
                    @Override
                    public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
                        if (!queryDocumentSnapshots.isEmpty()) {
                            for (QueryDocumentSnapshot journals : queryDocumentSnapshots) {
                                Journal journal = journals.toObject(Journal.class);
                                journalList.add(journal);
                            }
                            // Povikuvanje na RECYCLERVIEW
                            journalRecyclerAdapter = new JournalRecyclerAdapter(JournalListActivity.this, journalList);
                            recyclerView.setAdapter(journalRecyclerAdapter);
                            journalRecyclerAdapter.notifyDataSetChanged();

                        }else {
                            noJournalEntry.setVisibility(View.VISIBLE);
                        }
                    }
                })
                .addOnFailureListener(new OnFailureListener() {
                    @Override
                    public void onFailure(@NonNull Exception e) {

                    }
                });
    }
}

当我在 RecyclerView 上调用 setAdapter() 时，收到错误“未连接适配器；正在跳过布局”。即使我在从 Firestore 获取数据后在 onStart() 方法中设置适配器，也会发生这种情况

我已确保在添加新日记条目后调用notifyDataSetChanged()，并尝试在onCreate()中使用空列表设置适配器，但问题仍然存在。

关于如何解决这个问题有什么建议吗？

Answer 1

您收到以下消息，这是警告而不是错误：

E/RecyclerView：未连接适配器；跳过布局

因为您正在后台线程中的 Firebase

journalRecyclerAdapter

请求的回调中设置

get()

。

要解决此问题，您必须在回调的外部设置适配器并在其中设置适配器，只需通知它有关更改即可。所以请移动以下代码行：

journalRecyclerAdapter = new JournalRecyclerAdapter(JournalListActivity.this, journalList);
recyclerView.setAdapter(journalRecyclerAdapter);

之后：

journalList = new ArrayList<>();

并且在回调内部只保留以下代码行：

journalRecyclerAdapter.notifyDataSetChanged();

除此之外，也请不要再忽视错误。请至少添加：

Log.d("TAG", e.getMessage());

在你的

onFailure

里面。这样，您就可以随时知道读取数据的操作失败了。