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State

Flutter tutorial by examples

This is an animation example with SingleTickerProviderStateMixin.

//animation example
import 'package:flutter/material.dart';
import 'dart:math';

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

class AnimatedContainerApp extends StatefulWidget {
  _AnimatedContainerAppState createState() => _AnimatedContainerAppState();
}

class _AnimatedContainerAppState extends State
    with SingleTickerProviderStateMixin {
  double _width = 100;
  double _height = 100;
  Color _color = Colors.deepOrangeAccent;
  BorderRadiusGeometry _borderRadius = BorderRadius.circular(100.0);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Container(
            color: Colors.blueAccent,
            child: Center(
              child: AnimatedContainer(
                width: _width,
                height: _height,
                decoration: BoxDecoration(
                  borderRadius: _borderRadius,
                  color: _color,
                ),
                duration: const Duration(seconds: 1),
                curve: Curves.elasticOut,
              ),
            )),
        floatingActionButton: FloatingActionButton(
          child: const Icon(Icons.play_arrow),
          onPressed: () {
            setState(() {
              final random = Random();

              _width = random.nextInt(420).toDouble();
              _height = random.nextInt(420).toDouble();

              _color = Color.fromRGBO(random.nextInt(256), random.nextInt(256),
                  random.nextInt(256), 1);

              _borderRadius = BorderRadius.circular(
                random.nextInt(120).toDouble(),
              );
            });
          },
        ),
      ),
    );
  }
}

  

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