我可以正常创建并显示ExpansionPanelList.radio。它的children属性包含ExpansionPanelRadio个项目的列表。它可以正常工作-除了一件事：

当我导航至其他标签，然后返回包含我的ExpansionPanelList.radio的标签时，先前展开的ExpansionPanelRadio项现在被折叠。

我希望能够保留最后一个扩展的ExpansionPanelRadio的扩展名，但是它的isExpanded属性是只读的。与ExpansionPanel不同，ExpansionPanelRadio并未在其构造函数中定义isExpanded。

关于如何实现此目标的任何想法？ 谢谢！

编辑：为清楚起见，这是显示EpxpansionPalnelList.radio的代码：

class ProductsByApplicationWidget extends StatelessWidget {
  final ProductsByApplication productsByApplication;
  final int indexOfExpandedFieldOfApplication;

  const ProductsByApplicationWidget(
      {Key key,@required this.productsByApplication,@required this.indexOfExpandedFieldOfApplication})
      : assert(productsByApplication != null),assert(indexOfExpandedFieldOfApplication != null),super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      child: _buildPanel(),);
  }

  Widget _buildPanel() {
    return ExpansionPanelList.radio(
      animationDuration: Duration(milliseconds: 300),children:
      productsByApplication.productsForApplicationList
          .map<ExpansionPanel>((ProductsForApplication productsForApplication) {
        return ExpansionPanelRadio(
          canTapOnHeader: true,headerBuilder: (BuildContext context,bool isExpanded) {
            return FieldOfApplicationHeaderCellWidget(application: productsForApplication.application,);
          },body: Container(
            child: Padding(
              padding: const EdgeInsets.symmetric(horizontal: 8.0),child: Column(
                children:
                productsForApplication.products.map<ProductCellWidget>((Product product) {
                  return ProductCellWidget(product: product);
                }).toList(),),value: productsForApplication.application.id,);
      }).toList(),);
  }
}