# 基礎layout ### Scaffold 有默認的banner, background color, 提供API讓你新增 drawers, snack bars, 和 bottom sheets。 ```java void main() { runApp(MaterialApp( title: 'flutter_demo', home: Scaffold( appBar: AppBar( title: Text('Flutter layout demo'), ), body: Center(child:Text('name : jess')), )); } ``` ![](https://i.imgur.com/s7VSivC.png =50%x) --- #### 加入右下角的按鈕 ```java class Home extends StatelessWidget { @override Widget build(BuildContext context) { return Center(); } } void main() { runApp(MaterialApp( title: 'flutter_demo', home: Scaffold( appBar: AppBar( title: Text('Flutter layout demo'), ), body: Center(child:Text('name : jess')), floatingActionButton: FloatingActionButton( onPressed: null, child: const Icon(Icons.add))), )); } ``` ![](https://i.imgur.com/xVya2xT.png =50%x) --- ### 修改背景顏色 ```java void main() { runApp(MaterialApp( debugShowCheckedModeBanner: false, title: 'flutter_demo', home: Scaffold( appBar: AppBar( title: Text('Flutter layout demo'), ), body: Home(), backgroundColor: Colors.blueGrey.shade200, ), )); } ``` ![](https://i.imgur.com/DEeThXg.png =50%x) --- ### 修改app主題顏色 ```java return MaterialApp( //... theme: ThemeData( primaryColor: Colors.red, primaryColorDark: Colors.red, accentColor: Colors.red, )); ``` ![](https://i.imgur.com/tIzRKcd.png =50%x) --- ### 其他地方吃主色 ```java color: Theme.of(context).primaryColor, ```