main.dart:
import 'package:flutter/material.dart'; //import 'MyHomePage.dart'; import 'expansion_tile.dart'; void main()=>runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme:ThemeData.dark(), home: ExpansionTileDemo() ); } } expansion_tile.dart: import 'package:flutter/material.dart'; class ExpansionTileDemo extends StatefulWidget { @override _ExpansionTileDemoState createState() => _ExpansionTileDemoState(); } class _ExpansionTileDemoState extends State<ExpansionTileDemo> with SingleTickerProviderStateMixin { Animation animation; AnimationController animationController; @override void initState() { super.initState(); animationController = new AnimationController( vsync: this, duration: Duration(microseconds: 200)); animation = new Tween(begin: 0.0, end: 0.5).animate(animationController); } _changeOpacity(bool expand) { setState(() { if (expand) { animationController.forward(); } else { animationController.reverse(); } }); } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: Text('expansion title demo')), body: ListView( children: <Widget>[ ExpansionTile( title: const Text('更多精彩'), leading: Icon(Icons.ac_unit), trailing: RotationTransition(turns: animation,child: Icon(Icons.chevron_right)), backgroundColor: Colors.white12, onExpansionChanged: (bool){ _changeOpacity(bool); }, children: <Widget>[ Container( decoration: BoxDecoration( borderRadius: BorderRadius.circular(3.0), color: Colors.blueAccent, ), height: 100.0, margin: EdgeInsets.all(5.0), ), ]), ], ), ); } }
