相关疑难解决方法(0)

我想DraggableScrollableSheet在我的应用程序上使用小部件，当我使用下面的代码时，可以毫无问题地显示：

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('DraggableScrollableSheet'),
      ),
      body: SizedBox.expand(
        child: DraggableScrollableSheet(
          builder: (BuildContext context, ScrollController scrollController) {
            return Container(
              color: Colors.blue[100],
              child: ListView.builder(
                controller: scrollController,
                itemCount: 25,
                itemBuilder: (BuildContext context, int index) {
                  return ListTile(title: Text('Item $index'));
                },
              ),
            );
          },
        ),
      ),
    );
  }
}

但是当我想通过按例如floatingActionButton不显示来显示时

floatingActionButton: GestureDetector(
  child: FloatingActionButton(
    child: Icon(
      Icons.add,
      size: 35.0,
    ),
    elevation: 5,
    backgroundColor: Colors.deepOrange,
    foregroundColor: Colors.white,
    onPressed: …