flutter child.hasSize 错误

当在listview中嵌套Griview组件的时候，千万别忘记给Griview外层的Container添加高度哦

···
body: ListView(
children: [
// 导航条
Container(
height: 180, //new line
padding: EdgeInsets.only(top:10 ),
child: GridView.count(
crossAxisCount: 4,
mainAxisSpacing: 10,
…
···