How to add widget on tree using slide animation on onpressed flutter - flutter

Question

I need to add widgets using slide animation into tree on an action done on onpressed
the parent widget will be a listview in which the childrens will be added in slide down animation

Answer 1

import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Home(),
);
}
}
class Home extends StatefulWidget {
#override
State<StatefulWidget> createState() => HomeState();
}
class HomeState extends State<Home> with SingleTickerProviderStateMixin {
AnimationController controller;
Animation<Offset> offset;
#override
void initState() {
super.initState();
controller =
AnimationController(vsync: this, duration: Duration(seconds: 1));
offset = Tween<Offset>(begin: Offset.zero, end: Offset(0.0, 1.0))
.animate(controller);
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: Stack(
children: <Widget>[
Center(
child: RaisedButton(
child: Text('Show / Hide'),
onPressed: () {
switch (controller.status) {
case AnimationStatus.completed:
controller.reverse();
break;
case AnimationStatus.dismissed:
controller.forward();
break;
default:
}
},
),
),
Align(
alignment: Alignment.bottomCenter,
child: SlideTransition(
position: offset,
child: Padding(
padding: EdgeInsets.all(50.0),
child: CircularProgressIndicator(),
),
),
)
],
),
);
}
}