flutter 有状态组件传值方式

最新推荐文章于 2024-08-20 11:25:13 发布

原创

最新推荐文章于 2024-08-20 11:25:13 发布 · 1.2k 阅读

2 ·

CC 4.0 BY-SA版权

文章标签：

#flutter #StatefulWidget #有状态传值

这篇博客展示了如何在Flutter中创建一个购物应用。应用包含一个`ShoppingList`类，它扩展了`StatefulWidget`，并维护了一个产品列表。`_ShoppingListState`类处理购物车状态，当用户更改购物车中的商品时，通过`_handleCartChanged`方法更新 `_shoppingCart` 并触发视图重建。应用的主要组件包括`AppBar`、`ListView`，用于显示每个产品的`ShoppingListItem`。

class ShoppingList extends StatefulWidget {
  ShoppingList({Key key, this.products}) : super(key: key);

  final List<Product> products;

  // The framework calls createState the first time a widget
  // appears at a given location in the tree.
  // If the parent rebuilds and uses the same type of
  // widget (with the same key), the framework re-uses the State object
  // instead of creating a new State object.

  @override
  _ShoppingListState createState() => _ShoppingListState();
}

class _ShoppingListState extends State<ShoppingList> {
  Set<Product> _shoppingCart = Set<Product>();

  void _handleCartChanged(Product product, bool inCart) {
    setState(() {
      // When a user changes what's in the cart, you need to change
      // _shoppingCart inside a setState call to trigger a rebuild.
      // The framework then calls build, below,
      // which updates the visual appearance of the app.

      if (!inCart)