使用picker，当我选择之后，导航栏的背景就会变，本来是白色的导航栏，会变成默认的好像

[Clancecy]

Picker picker = Picker( adapter: NumberPickerAdapter(data: [ const NumberPickerColumn( begin: 14, end: 99, initValue: 18, suffix: Text(" 岁"), ), ]), headerDecoration: const BoxDecoration( border: Border(bottom: BorderSide(color: Colors.black12, width: 0.5)), ), hideHeader: true, );