要解决Android RecyclerView无法从数据库获取数据的问题，你需要执行以下步骤：

1. 确保你已经设置好了数据库，并正确地插入了数据。可以使用以下代码示例来创建数据库和插入数据：

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "your_database_name";
    private static final int DATABASE_VERSION = 1;
    private static final String TABLE_NAME = "your_table_name";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_NAME = "name";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String createTableQuery = "CREATE TABLE " + TABLE_NAME + " (" +
                COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                COLUMN_NAME + " TEXT)";
        db.execSQL(createTableQuery);
    }

    public void insertData(String name) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COLUMN_NAME, name);
        db.insert(TABLE_NAME, null, contentValues);
        db.close();
    }
}

2. 确保在你的RecyclerView的适配器中正确地从数据库获取数据。可以使用以下代码示例来实现适配器：

public class MyAdapter extends RecyclerView.Adapter {
    private List dataList;
    private DatabaseHelper databaseHelper;

    public MyAdapter(Context context) {
        databaseHelper = new DatabaseHelper(context);
        dataList = databaseHelper.getData();
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        String data = dataList.get(position);
        holder.textView.setText(data);
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {
        TextView textView;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.text_view);
        }
    }
}

3. 在你的MainActivity中初始化RecyclerView并设置适配器。可以使用以下代码示例：

public class MainActivity extends AppCompatActivity {
    private RecyclerView recyclerView;
    private MyAdapter adapter;

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

        recyclerView = findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));

        adapter = new MyAdapter(this);
        recyclerView.setAdapter(adapter);
    }
}

通过以上步骤，你的Android RecyclerView应该能够从数据库获取数据并正确地显示在列表中。请确保你的数据库中已经插入了数据，并检查适配器中从数据库获取数据的代码是否正确。