|  | 
| 6 | 6 | 
 | 
| 7 | 7 | import 'package:flutter/material.dart'; | 
| 8 | 8 | 
 | 
| 9 |  | -void main() => runApp(const MyApp()); | 
|  | 9 | +final List<int> _items = List<int>.generate(51, (int index) => index); | 
| 10 | 10 | 
 | 
| 11 |  | -class MyApp extends StatelessWidget { | 
| 12 |  | -  const MyApp({super.key}); | 
|  | 11 | +void main() => runApp(const AppBarApp()); | 
| 13 | 12 | 
 | 
| 14 |  | -  static const String _title = 'Flutter Code Sample'; | 
|  | 13 | +class AppBarApp extends StatelessWidget { | 
|  | 14 | +  const AppBarApp({super.key}); | 
| 15 | 15 | 
 | 
| 16 | 16 |   @override | 
| 17 | 17 |   Widget build(BuildContext context) { | 
| 18 |  | -    return const MaterialApp( | 
| 19 |  | -      title: _title, | 
| 20 |  | -      home: MyStatelessWidget(), | 
|  | 18 | +    return MaterialApp( | 
|  | 19 | +      theme: ThemeData( | 
|  | 20 | +        colorSchemeSeed: const Color(0xff6750a4), | 
|  | 21 | +        useMaterial3: true, | 
|  | 22 | +      ), | 
|  | 23 | +      home: const AppBarExample(), | 
| 21 | 24 |     ); | 
| 22 | 25 |   } | 
| 23 | 26 | } | 
| 24 | 27 | 
 | 
| 25 |  | -class MyStatelessWidget extends StatelessWidget { | 
| 26 |  | -  const MyStatelessWidget({super.key}); | 
|  | 28 | +class AppBarExample extends StatefulWidget { | 
|  | 29 | +  const AppBarExample({super.key}); | 
|  | 30 | + | 
|  | 31 | +  @override | 
|  | 32 | +  State<AppBarExample> createState() => _AppBarExampleState(); | 
|  | 33 | +} | 
|  | 34 | + | 
|  | 35 | +class _AppBarExampleState extends State<AppBarExample> { | 
|  | 36 | +  bool shadowColor = false; | 
|  | 37 | +  double? scrolledUnderElevation; | 
| 27 | 38 | 
 | 
| 28 | 39 |   @override | 
| 29 | 40 |   Widget build(BuildContext context) { | 
| 30 |  | -    final ButtonStyle style = | 
| 31 |  | -        TextButton.styleFrom(primary: Theme.of(context).colorScheme.onPrimary); | 
|  | 41 | +    final ColorScheme colorScheme = Theme.of(context).colorScheme; | 
|  | 42 | +    final Color oddItemColor = colorScheme.primary.withOpacity(0.05); | 
|  | 43 | +    final Color evenItemColor = colorScheme.primary.withOpacity(0.15); | 
|  | 44 | + | 
| 32 | 45 |     return Scaffold( | 
| 33 | 46 |       appBar: AppBar( | 
| 34 |  | -        actions: <Widget>[ | 
| 35 |  | -          TextButton( | 
| 36 |  | -            style: style, | 
| 37 |  | -            onPressed: () {}, | 
| 38 |  | -            child: const Text('Action 1'), | 
| 39 |  | -          ), | 
| 40 |  | -          TextButton( | 
| 41 |  | -            style: style, | 
| 42 |  | -            onPressed: () {}, | 
| 43 |  | -            child: const Text('Action 2'), | 
|  | 47 | +        title: const Text('AppBar Demo'), | 
|  | 48 | +        scrolledUnderElevation: scrolledUnderElevation, | 
|  | 49 | +        shadowColor: shadowColor ? Theme.of(context).colorScheme.shadow : null, | 
|  | 50 | +      ), | 
|  | 51 | +      body: GridView.builder( | 
|  | 52 | +        shrinkWrap: true, | 
|  | 53 | +        itemCount: _items.length, | 
|  | 54 | +        padding: const EdgeInsets.all(8.0), | 
|  | 55 | +        gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount( | 
|  | 56 | +          crossAxisCount: 3, | 
|  | 57 | +          childAspectRatio: 2.0, | 
|  | 58 | +          mainAxisSpacing: 10.0, | 
|  | 59 | +          crossAxisSpacing: 10.0, | 
|  | 60 | +        ), | 
|  | 61 | +        itemBuilder: (BuildContext context, int index) { | 
|  | 62 | +          if (index == 0) { | 
|  | 63 | +            return Center( | 
|  | 64 | +              child: Text( | 
|  | 65 | +                'Scroll to see the Appbar in effect.', | 
|  | 66 | +                style: Theme.of(context).textTheme.labelLarge, | 
|  | 67 | +                textAlign: TextAlign.center, | 
|  | 68 | +              ), | 
|  | 69 | +            ); | 
|  | 70 | +          } | 
|  | 71 | +          return Container( | 
|  | 72 | +            alignment: Alignment.center, | 
|  | 73 | +            // tileColor: _items[index].isOdd ? oddItemColor : evenItemColor, | 
|  | 74 | +            decoration: BoxDecoration( | 
|  | 75 | +              borderRadius: BorderRadius.circular(20.0), | 
|  | 76 | +              color: _items[index].isOdd ? oddItemColor : evenItemColor, | 
|  | 77 | +            ), | 
|  | 78 | +            child: Text('Item $index'), | 
|  | 79 | +          ); | 
|  | 80 | +        }, | 
|  | 81 | +      ), | 
|  | 82 | +      bottomNavigationBar: BottomAppBar( | 
|  | 83 | +        child: Padding( | 
|  | 84 | +          padding: const EdgeInsets.all(8), | 
|  | 85 | +          child: OverflowBar( | 
|  | 86 | +            overflowAlignment: OverflowBarAlignment.center, | 
|  | 87 | +            alignment: MainAxisAlignment.center, | 
|  | 88 | +            overflowSpacing: 5.0, | 
|  | 89 | +            children: <Widget>[ | 
|  | 90 | +              ElevatedButton.icon( | 
|  | 91 | +                onPressed: () { | 
|  | 92 | +                  setState(() { | 
|  | 93 | +                    shadowColor = !shadowColor; | 
|  | 94 | +                  }); | 
|  | 95 | +                }, | 
|  | 96 | +                icon: Icon( | 
|  | 97 | +                  shadowColor ? Icons.visibility_off : Icons.visibility, | 
|  | 98 | +                ), | 
|  | 99 | +                label: const Text('shadow color'), | 
|  | 100 | +              ), | 
|  | 101 | +              const SizedBox(width: 5), | 
|  | 102 | +              ElevatedButton.icon( | 
|  | 103 | +                onPressed: () { | 
|  | 104 | +                  if (scrolledUnderElevation == null) { | 
|  | 105 | +                    setState(() { | 
|  | 106 | +                      // Default elevation is 3.0, increment by 1.0. | 
|  | 107 | +                      scrolledUnderElevation = 4.0; | 
|  | 108 | +                    }); | 
|  | 109 | +                  } else { | 
|  | 110 | +                    setState(() { | 
|  | 111 | +                      scrolledUnderElevation = scrolledUnderElevation! + 1.0; | 
|  | 112 | +                    }); | 
|  | 113 | +                  } | 
|  | 114 | +                }, | 
|  | 115 | +                icon: const Icon(Icons.add), | 
|  | 116 | +                label: Text( | 
|  | 117 | +                  'scrolledUnderElevation: ${scrolledUnderElevation ?? 'default'}', | 
|  | 118 | +                ), | 
|  | 119 | +              ), | 
|  | 120 | +            ], | 
| 44 | 121 |           ), | 
| 45 |  | -        ], | 
|  | 122 | +        ), | 
| 46 | 123 |       ), | 
| 47 | 124 |     ); | 
| 48 | 125 |   } | 
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