Android读取SQLite数据存入List时RecyclerView不显示且Cursor报错

尝试读取SQLite数据库中的全部数据并展示到RecyclerView时，列表无任何内容，同时应用抛出如下异常：

E/CursorWindow: Failed to read row 0, column 3 from a CursorWindow which has 4 rows, 3 columns.
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.uspherejda, PID: 7434
    java.lang.IllegalStateException: Couldn't read row 0, col 3 from CursorWindow.  Make sure the Cursor is initialized correctly before accessing data from it.

代码存在三处明显问题：

• Cursor列索引取值错误：SQL查询返回的游标列索引从0开始计数，你查询的三个字段name、country、category对应的索引分别为0、1、2，但是代码中使用getString(1)、getString(2)、getString(3)取值，尝试读取不存在的第3列，直接触发越界崩溃。
• Cursor遍历逻辑错误：先调用c.moveToFirst()将游标定位到第一条数据，循环条件又直接执行c.moveToNext()，会直接跳过第一条数据，如果库中只有1条数据，循环根本不会执行，返回的列表为空。
• 插入数据参数顺序错误：SatelliteForm有参构造的参数顺序为(name, country, category)，但插入数据时你传入的参数是(卫星名, 分类名, 国家名)，导致国家和分类字段的存储值完全颠倒。

1. 修复数据库查询逻辑 #

public ArrayList<SatelliteForm> getAllData(SQLiteDatabase sqLiteDatabase){
    ArrayList<SatelliteForm> arraySatelite = new ArrayList<>();
    sqLiteDatabase = this.getWritableDatabase();
    String SELECT_QUERY = "select name, country, category from " + SatFormContracts.ContactsEntry.TABLE_NAME + ";";
    Cursor c = sqLiteDatabase.rawQuery(SELECT_QUERY, null);
    // 移除多余的moveToFirst，直接用moveToNext遍历所有数据
    while(c.moveToNext()){
        SatelliteForm form = new SatelliteForm();
        // 索引改为从0开始
        form.setName(c.getString(0));
        form.setCountry(c.getString(1));
        form.setCategory(c.getString(2));
        arraySatelite.add(form);
        Log.i("nameSQL", c.getString(0) + "" + c.getString(1) + "" + c.getString(2));
    }
    c.close();
    return arraySatelite;
}

2. 修复插入数据参数顺序 #

public void onClick(View view) {
    if(!(satName.getText().toString().isEmpty() || countryName.getText().toString().isEmpty() || categoryName.getText().toString().isEmpty())){
        // 调整参数顺序为(name, country, category)
        SatelliteForm addForm = new SatelliteForm(satName.getText().toString(),
                                                  countryName.getText().toString(),
                                                  categoryName.getText().toString());
        dbHelper.insertContact(db, addForm);
        saveState.setText("保存成功!");
    }else{
        saveState.setText("存在未填写的字段");
        Log.i("Campos", "Unos de los campos esta vacio");
    }
}

为了避免手动写列索引出错，推荐通过字段名获取索引：

int nameIndex = c.getColumnIndexOrThrow("name");
int countryIndex = c.getColumnIndexOrThrow("country");
int categoryIndex = c.getColumnIndexOrThrow("category");
form.setName(c.getString(nameIndex));
form.setCountry(c.getString(countryIndex));
form.setCategory(c.getString(categoryIndex));

内容的提问来源于stack exchange，提问作者noobieCoder