Created
March 11, 2020 00:08
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AnimatedList example
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import 'package:flutter/material.dart'; | |
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final Color darkBlue = Color.fromARGB(255, 18, 32, 47); | |
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void main() { | |
runApp(MyApp()); | |
} | |
| |
class MyApp extends StatelessWidget { | |
@override | |
Widget build(BuildContext context) { | |
return MaterialApp( | |
theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue), | |
debugShowCheckedModeBanner: false, | |
home: Scaffold( | |
body: Center( | |
child: MyWidget(), | |
), | |
), | |
); | |
} | |
} | |
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class MyWidget extends StatelessWidget { | |
@override | |
Widget build(BuildContext context) { | |
return AnimatedListInfo(); | |
} | |
} | |
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| |
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class AnimatedListInfo extends StatefulWidget { | |
@override | |
_AnimatedListInfoState createState() => _AnimatedListInfoState(); | |
} | |
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class _AnimatedListInfoState extends State<AnimatedListInfo> { | |
List items = [0, 1, 2]; | |
bool isExpanded = true; | |
static const double containerHeight = 100; | |
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var duration = Duration(milliseconds: 200); | |
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@override | |
Widget build(BuildContext context) { | |
return AnimatedContainer( | |
duration: duration, | |
height: containerHeight * (isExpanded ? 3 : 1), | |
child: AnimatedList( | |
shrinkWrap: true, | |
initialItemCount: items.length, | |
itemBuilder: | |
(BuildContext context, int index, Animation<double> animation) { | |
return SlideTransition( | |
position: | |
animation.drive(Tween(begin: Offset(0, 1), end: Offset(0, 0))), | |
child: FlatButton( | |
child: AnimatedOpacity( | |
opacity: opacity(index), | |
duration: duration, | |
child: buildContainer(index), | |
), | |
onPressed: () { | |
if (isExpanded) { | |
AnimatedList.of(context) | |
..removeItem( | |
index, | |
(context, animation) => Opacity( | |
opacity: animation.value, | |
child: buildContainer(index), | |
)) | |
..insertItem(0); | |
setState(() { | |
var value = items.removeAt(index); | |
items.insert(0, value); | |
isExpanded = false; | |
}); | |
} else { | |
setState(() { | |
isExpanded = true; | |
}); | |
} | |
}, | |
), | |
); | |
}, | |
), | |
); | |
} | |
| |
Container buildContainer(int index) { | |
return Container( | |
width: 100, | |
height: 100, | |
decoration: BoxDecoration(color: Colors.red, border: Border.all()), | |
child: Text( | |
items[index].toString(), | |
style: TextStyle(fontSize: 30), | |
), | |
); | |
} | |
| |
double opacity(int index) { | |
if (isExpanded || index == 0) { | |
return 1.0; | |
} else { | |
return 0; | |
} | |
} | |
} | |
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