小编use*_*983的帖子

When I try to set the border radius of the top two corners of my container that is nested inside a card, the whole content of the container goes disappears. Here is my code, if you uncomment the commented line your whole content inside the container will go away.

Widget build(BuildContext context) {
    return Card(
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(5.0),
      ),
      margin: new EdgeInsets.symmetric(horizontal: 10.0, vertical: 6.0),
      child: Container(
        decoration: BoxDecoration(
          border: new Border(
              top: BorderSide(
            color: Theme.of(context).primaryColor,
            width: 3.0,
          )), …

我是扑的新手。我正在尝试将 bottomappbar 小部件与主屏幕分开。问题是，我需要将索引发送回主屏幕文件，以便我可以切换屏幕主体。我最近一直在学习 BloC，但我认为这对于这种情况来说有点矫枉过正，即使我将在应用程序的其他部分使用它（希望这是正确的假设）。那么，如何将索引发送给父级？

家长

class HomeScreen extends StatefulWidget {
  @override
  _HomeScreenState createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  int _selectedIndex = 0;
  final _bottomNavigationPages = [
    Screen1(),
    Screen2(),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        iconTheme: IconThemeData(
          color: Colors.blueGrey,
        ),
        title:
            Text('xxx', style: new TextStyle(fontWeight: FontWeight.w400)),
      ),
      body: _bottomNavigationPages[_selectedIndex],
      bottomNavigationBar: HomeBottomAppBar(),
    );
  }
}

孩子

class HomeBottomAppBar extends StatefulWidget {
  @override
  _HomeBottomAppBarState createState() => _HomeBottomAppBarState();
}

class _HomeBottomAppBarState extends State<HomeBottomAppBar> {
  int _selectedIndex = …

我正在尝试在我的颤振主题上使用自定义颜色，如下所示：

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Onelog',
        theme: ThemeData(
          primarySwatch: MyColors.navy,
          primaryTextTheme: TextTheme(title: TextStyle(color: Colors.black)),
        ),
        //Code...
  }
}

class MyColors {
  static const Color navy = const Color(0xFF162A49);
}

但这说明 Color 不是 Material color 的子类型