flutter - 创建表语句中的SQLite语法错误-Flutter/Dart

Question

我不断收到此语法错误:E / SQLiteLog(4514):(1)靠近“空”:“创建表消费表(id整数主键自动增加，空文本，空文本)”中的语法错误
我对此很陌生，并且一直在网上使用示例将这些代码放在一起，但我似乎找不到导致此问题的原因。
任何帮助将不胜感激!
'''

import 'dart:io';
import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';
import 'dart:async';
import 'expense_list.dart';

class ExpensesDatabase {
  static ExpensesDatabase _expensesDatabase;
  static Database _database;

  String expensesTable = 'expenses_table';

  String id = 'id';
  String name;
  String amount;

  ExpensesDatabase._createInstance();

  factory ExpensesDatabase() {
    if (_expensesDatabase == null) {
      _expensesDatabase = ExpensesDatabase._createInstance();
    }
    return _expensesDatabase;
  }

  Future<Database> get database async {
    if (_database == null) {
      _database = await initializeDatabase();
    }
    return _database;
  }

  Future<Database> initializeDatabase() async {
    Directory directory = await getApplicationDocumentsDirectory();
    String path = directory.path + 'expenses.db';

    var expensesDatabase =
        await openDatabase(path, version: 1, onCreate: _createDb);
    return expensesDatabase;
  }

  void _createDb(Database db, int newVersion) async {
    await db.execute(
        'CREATE TABLE $expensesTable($id INTEGER PRIMARY KEY AUTOINCREMENT,'
        '$name TEXT,'
        '$amount TEXT)');
  }

'''

Answer 1

初始化您的名称和数量变量，由于字符串名称和数量尚未初始化，因此该变量为null。

String name = 'name';
String amount = 'amount';