flutter_semina_livecode.dart

import 'dart:math';

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String name = "hello";

  List<Color> colors = [Colors.red, Colors.black, Colors.blue, Colors.amber];

  Color color = Colors.red;
  double width = 100.0;
  double height = 100.0;
  Random random = Random();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text(widget.title),
        ),
        floatingActionButton: FloatingActionButton(
          child: Icon(Icons.cached),
          onPressed: () {
          setState(() {
            color = colors[random.nextInt(3)];
            width = 100.0 + random.nextInt(100);
            height = 100.0 + random.nextInt(300);
          });
        }),
        body: Center(
            child:
                AnimatedContainer(
                  curve: Curves.easeInOutBack,
                  duration: Duration(milliseconds: 500),
                  width: width, height: height, color: color)));
  }
}