How can I animate a Dialog in Flutter like this

Question

I'm trying to animate an alert dialog in flutter so that when it pop ups it shows an animation like this below.

How can I achieve following look and behaviour from Pokemon Go in an alertDialog?

I would really like to have this animation in my app.

Thanks for your Answers!

Answer 1

Try this, modify any variable to meet your requirement:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with TickerProviderStateMixin {
  AnimationController _controller;
  Animation<Offset> _animation;
  double _width = 20;
  double _height = 200;
  Color _color = Colors.transparent;

  @override
  void initState() {
    super.initState();

    _controller = AnimationController(
      duration: const Duration(seconds: 1),
      vsync: this,
    );
    _animation = Tween<Offset>(
      begin: const Offset(0.0, 1.0),
      end: const Offset(0.0, -2.0),
    ).animate(CurvedAnimation(
      parent: _controller,
      curve: Curves.easeInCubic,
    ));
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.black,
      appBar: AppBar(
        actions: [
          IconButton(
            icon: Icon(Icons.send),
            onPressed: () {
              setState(() {
                _color = Colors.white;
              });
              _controller.forward().then((_) {
                _width = 200;
                setState(() {});
              });
            },
          ),
        ],
      ),
      body: Stack(
        children: [
          Align(
            alignment: Alignment.bottomCenter,
            child: SlideTransition(
              position: _animation,
              child: AnimatedContainer(
                width: _width,
                height: _height,
                decoration: BoxDecoration(
                  color: _color,
                  borderRadius: BorderRadius.circular(10),
                ),
                duration: Duration(seconds: 1),
                curve: Curves.fastOutSlowIn,
              ),
            ),
          ),
        ],
      ),
    );
  }
}