flutter/examples/api/lib/widgets/transitions/default_text_style_transition.0.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/// Flutter code sample for [DefaultTextStyleTransition].

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: _title,
      home: MyStatefulWidget(),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({super.key});

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

/// [AnimationController]s can be created with `vsync: this` because of
/// [TickerProviderStateMixin].
class _MyStatefulWidgetState extends State<MyStatefulWidget>
    with TickerProviderStateMixin {
  late AnimationController _controller;
  late TextStyleTween _styleTween;
  late CurvedAnimation _curvedAnimation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(seconds: 2),
      vsync: this,
    )..repeat(reverse: true);
    _styleTween = TextStyleTween(
      begin: const TextStyle(
          fontSize: 50, color: Colors.blue, fontWeight: FontWeight.w900),
      end: const TextStyle(
          fontSize: 50, color: Colors.red, fontWeight: FontWeight.w100),
    );
    _curvedAnimation = CurvedAnimation(
      parent: _controller,
      curve: Curves.elasticInOut,
    );
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: DefaultTextStyleTransition(
        style: _styleTween.animate(_curvedAnimation),
        child: const Text('Flutter'),
      ),
    );
  }
}