TypeError (type 'int' is not a subtype of type 'double') flutter

Question

我正在尝试执行 http.get 请求以获取我已经发布（完美运行）到 firebase（实时存储）的数据，但是当我从未调用获取数据的方法时，它会抛出错误_TypeError（类型'int'不是类型'double'的子类型）请注意，我正在使用提供者状态管理

下面是用来fecth我的数据的方法

Future<void> getAndSetProducts() async {
    const url = 'https://shop-12901-default-rtdb.firebaseio.com/products.json';
    try {
      final response = await http.get(Uri.parse(url));
      var extractedResponse =
          json.decode(response.body) as Map<String, dynamic>;
      List<Product> loadedProducts = [];
      extractedResponse.forEach((prodId, product) {
        loadedProducts.add(
          Product(
            id: prodId,
            title: product['title'],
            price: product['price'], //-Sure the error is from here but not sure of how to resolve it-
            imageUrl: product['imageUrl'],
            description: product['description'],
            isFavorite: product['isFavorite'],
          ),
        );
      });
      _items = loadedProducts;
      notifyListeners();
    } catch (error) {
      throw error; //--------TypeError (type 'int' is not a subtype of type 'double')-------
    }
  }

下面也是我调用上面的方法来执行其任务的方法

@override
  void didChangeDependencies() {
    if (_isInit) {
      setState(() {
      isLoading = true;
    });
      try {
        Provider.of<Products>(context).getAndSetProducts().then((_) {
          setState(() {
            isLoading = false;
          });
        });
      } catch (error) {
        print(error);
      }
    }
    _isInit = false;
    super.didChangeDependencies();
  }

Answer 1

您可以在代码后使用 .toDouble() 函数（示例：-> product['price'].toDouble）或者您可以在代码后使用 double.parse(value) 函数（示例：-> double.parse(product['price']))

Answer 2

尝试以 num 形式获取价格，然后将其解析为 double。

Future<void> getAndSetProducts() async {
    const url = 'https://shop-12901-default-rtdb.firebaseio.com/products.json';
    try {
      final response = await http.get(Uri.parse(url));
      var extractedResponse =
          json.decode(response.body) as Map<String, dynamic>;
      List<Product> loadedProducts = [];
      extractedResponse.forEach((prodId, product) {
        loadedProducts.add(
          Product(
            id: prodId,
            title: product['title'],
            price: (product['price'] as num).toDouble(), //Try this
            imageUrl: product['imageUrl'],
            description: product['description'],
            isFavorite: product['isFavorite'],
          ),
        );
      });
      _items = loadedProducts;
      notifyListeners();
    } catch (error) {
      throw error; //--------TypeError (type 'int' is not a subtype of type 'double')-------
    }
  }

TypeError (type 'int' is not a subtype of type 'double') flutter

TypeError (type 'int' is not a subtype of type 'double') flutter

dart

firebase

firebase-realtime-database

flutter