如何向ExpansionPanelList - ListView.Builder添加子项？

List<ItemData> itemList = [
  ItemData(title: 'Item 1', content: 'Content 1'),
  ItemData(title: 'Item 2', content: 'Content 2'),
  ItemData(title: 'Item 3', content: 'Content 3'),
];

ExpansionPanelList(
  children: [
    ListView.builder(
      shrinkWrap: true,
      physics: NeverScrollableScrollPhysics(),
      itemCount: itemList.length,
      itemBuilder: (context, index) {
        return ExpansionPanel(
          headerBuilder: (context, isExpanded) {
            return ListTile(
              title: Text(itemList[index].title),
            );
          },
          body: ListTile(
            title: Text(itemList[index].content),
          ),
          isExpanded: itemList[index].isExpanded,
        );
      },
    ),
  ],
  expansionCallback: (index, isExpanded) {
    setState(() {
      itemList[index].isExpanded = !isExpanded;
    });
  },
);