错误：flutter/runtime/dart_vm_initializer.cc(41) 未处理的异常：类型“String”不是“index”的“int”类型的子类型

Question

我运行时遇到此错误：

[错误：flutter/runtime/dart_vm_initializer.cc(41)] 未处理的异常：类型“String”不是“index”#0 的“int”类型的子类型

Products.fetchAndSetProducts（包：my_shop/providers/products.dart：60：7）

我认为 Firebase 数据库一定有问题。

这是我的 products.dart 代码

import 'dart:io';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
import 'package:my_shop/providers/product.dart';

class Products with ChangeNotifier {
  List<Product> _items = [];

  final String authToken;
  final String userId;
  Products(this.authToken, this.userId, this._items);

  //var _showFavoritesOnly = false;
  List<Product> get items {
    // if (_showFavoritesOnly) {
    //   return _items.where((prodItem) => prodItem.isFavorite).toList();
    // }
    return [..._items];
  }

  List<Product> get favoriteItems {
    return _items.where((prodItem) => prodItem.isFavorite).toList();
  }

  Product findById(String id) {
    return _items.firstWhere((prod) => prod.id == id);
  }

  Future<void> fetchAndSetProducts([bool filterByUser = false]) async {
    final filterString =
        filterByUser ? 'orderBy="creatorId"&equalTo="userId"' : '';
    var url = Uri.parse(
        'https://flutter-update-ced0c-default-rtdb.europe-west1.firebasedatabase.app/products.json?auth=$authToken&$filterString');
    try {
      final response = await http.get(url);
      final extractedData = json.decode(response.body) as Map<String, dynamic>;
      if (extractedData == null) {
        return;
      }
      url = Uri.parse(
          'https://flutter-update-ced0c-default-rtdb.europe-west1.firebasedatabase.app/userFavorites/$userId.json?auth=$authToken');
      final favoriteResponse = await http.get(url);
      final favoriteData = json.decode(favoriteResponse.body);

      final List<Product> loadedProducts = [];
      extractedData.forEach((prodId, prodData) {
        loadedProducts.add(Product(
            id: prodId,
            title: prodData['title'],
            description: prodData['description'],
            price: prodData['price'],
            isFavorite:
                favoriteData == null ? false : favoriteData[prodId] ?? false,
            imageUrl: prodData['imageUrl']));
      });
      _items = loadedProducts;
      notifyListeners();
    } catch (error) {
      throw (error);
    }
  }

  Future<void> addProduct(Product product) async {
    var url = Uri.parse(
        'https://flutter-update-ced0c-default-rtdb.europe-west1.firebasedatabase.app/products.json?auth=$authToken');
    try {
      final response = await http.post(
        url,
        body: json.encode({
          'title': product.title,
          'description': product.description,
          'price': product.price,
          'creatorId': userId,
          'imageUrl': product.imageUrl,
        }),
      );

      final newProduct = Product(
          id: json.decode(response.body)['name'],
          title: product.title,
          description: product.description,
          price: product.price,
          imageUrl: product.imageUrl);
      _items.add(newProduct);
      //_items.insert(0,newProduct);
      notifyListeners();
    } catch (error) {
      throw (error);
    }
  }

  Future<void> updateProduct(String id, Product newProduct) async {
    final prodcutIndex = _items.indexWhere((prod) => prod.id == id);
    if (prodcutIndex >= 0) {
      var url = Uri.parse(
          'https://flutter-update-ced0c-default-rtdb.europe-west1.firebasedatabase.app/products/$id.json?auth=$authToken');
      await http.patch(
        url,
        body: json.encode({
          'title': newProduct.title,
          'description': newProduct.description,
          'price': newProduct.price,
          'imageUrl': newProduct.imageUrl,
        }),
      );
      _items[prodcutIndex] = newProduct;
      notifyListeners();
    } else {
      print('...');
    }
  }

  Future<void> deleteProduct(String id) async {
    var url = Uri.parse(
        'https://flutter-update-ced0c-default-rtdb.europe-west1.firebasedatabase.app/products/$id.json?auth=$authToken');
    final existingProductIndex = _items.indexWhere((prod) => prod.id == id);
    Product? existingProduct = _items[existingProductIndex];
    _items.removeAt(existingProductIndex);
    notifyListeners();
    final response = await http.delete(url);
    if (response.statusCode >= 400) {
      _items.insert(existingProductIndex, existingProduct);
      notifyListeners();
      throw const HttpException('Could not delete the product!');
    }
    existingProduct = null;
  }
}

Answer 1

您提供的代码片段似乎正在将产品添加到名为

loadedProducts

的列表中。该错误可能与您处理价格数据的方式有关

(prodData['price'])

。确保

prodData['price']

确实返回一个整数值，因为它似乎在代码中的某处被视为字符串。

以下是处理此问题的方法：

1. 确保

   price

   地图中的

   prodData

   字段存储为整数。
2. 如果

   price

   存储为字符串，则需要先将其转换为整数，然后再将其分配给

   price

   的

   Product

   属性。

以下是如何将价格转换为整数的示例：

price: int.parse(prodData['price']),

此行会将

prodData['price']

的字符串值解析为整数。确保

prodData['price']

始终包含有效的整数表示形式，否则，您可能会遇到解析错误。