尝试使用 Scaffold.of(context) 使用 openDrawer() 找到 2 而不是 0 时出现太多位置 arguments 错误

Question

class MyApp extends StatelessWidget {
  @override

  Widget build(BuildContext context) {

   return MaterialApp(

        home: SafeArea(

            child: Scaffold(

      Builder(

          builder: (context) => AppBar(

                leading: IconButton(

                  icon: Icon(Icons.accessible),

                  onPressed: () => Scaffold.of(context).openDrawer(),

                ),
                title: Text('Sorted.'),
                backgroundColor: Color(0xff0A3D62),
              )),

      Drawer(

          child: ListView(padding: EdgeInsets.zero, children: <Widget>[

        new UserAccountsDrawerHeader(

          accountName: new Text('XYZ'),
          accountEmail: new Text('XYZ@gmail.com'),
          currentAccountPicture: new CircleAvatar(),
        )
      ])),

      body: Center(child: Home()),)

    ));
  }
}` 

Error: Too many positional arguments: 0 expected, but 2 found. Try removing the extra positional arguments, or specifying the name for named arguments.

Please help me resolve this. Thanks in advance!

Answer 1

This is because you cannot pass AppBar and Drawer parameters to Scaffold like this..

Scaffold(
    AppBar(),
    Drawer(),
)

..because these are named parameters. Instead, you need to pass them with the corresponding parameter names like..

Scaffold(
    appBar: AppBar(),
    drawer: Drawer(),
)

Answer 2

return MaterialApp(
    home: SafeArea(
        child: Scaffold(
  appBar: AppBar(
    leading: IconButton(
      icon: Icon(Icons.accessible),
      onPressed: () => Scaffold.of(context).openDrawer(),
    ),
    title: Text('Sorted.'),
    backgroundColor: Color(0xff0A3D62),
  ),
  drawer: Drawer(
      child: ListView(padding: EdgeInsets.zero, children: <Widget>[
    new UserAccountsDrawerHeader(
      accountName: new Text('XYZ'),
      accountEmail: new Text('XYZ@gmail.com'),
      currentAccountPicture: new CircleAvatar(),
    )
  ])),
  body: Center(child: Home()),
)));