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,
      ),
      home: Home(),
    );
  }
}

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
  bool _withAnimation = true;
  bool _isExtended = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Switch Fab sample'),
      ),
      body: Center(
        child: Column(
          children: [
            SwitchListTile.adaptive(
              title: Text('With animation'),
              value: _withAnimation,
              onChanged: (bool value) {
                setState(() {
                  _withAnimation = value;
                });
              },
            ),
            ElevatedButton(
              child: Text('Change Fab style!'),
              onPressed: () {
                setState(() {
                  _isExtended = !_isExtended;
                });
              },
            ),
          ],
        ),
      ),
      floatingActionButton: _withAnimation
          ? _buildFabWithAnimation()
          : _buildFabWithoutAnimation(),
    );
  }

  Widget _buildFabWithAnimation() {
    return FloatingActionButton.extended(
      onPressed: () {},
      label: AnimatedSwitcher(
        duration: Duration(milliseconds: 200),
        transitionBuilder: (Widget child, Animation<double> animation) =>
            FadeTransition(
          opacity: animation,
          child: SizeTransition(
            child: child,
            sizeFactor: animation,
            axis: Axis.horizontal,
          ),
        ),
        child: !_isExtended
            ? Icon(Icons.add)
            : Row(
                children: [
                  Padding(
                    padding: const EdgeInsets.only(right: 4.0),
                    child: Icon(Icons.add),
                  ),
                  Text("Add")
                ],
              ),
      ),
    );
  }

  Widget _buildFabWithoutAnimation() {
    return FloatingActionButton.extended(
      onPressed: () {},
      label: Text('Add'),
      icon: Icon(Icons.add),
      isExtended: _isExtended,
    );
  }
}