我在使用此代码时遇到错误 RenderFlex子级具有非零的弯曲，但传入的高度约束是无界的.
我的目标是将Listview显示为展开的列表视图，标题如"正在显示数据40".
Widget build(BuildContext context) {
return SafeArea(child: Scaffold(
body: Column(children: [
Container(
height: 40,
color: Colors.red,
child: Center(child: Text('A')),
),
Container(
height: 40,
color: Colors.green,
child: Center(child: Text('B')),
),
Container(
height: 40,
color: Colors.blue,
child: Center(child: Text('C')),
),
buildShowListView()
],),
));
}
Widget buildShowListView()
{
List<String> data=['1','2','3','4','5'];
return Column(children: [
Text('Showing Data ${data.length}'),
Expanded(
child: ListView.builder(
itemCount: 20,
itemBuilder: (context,index){
return Text('$index');
}),
)
],);
}