examples/api/lib/widgets/transitions/decorated_box_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.

// Template: dev/snippets/config/templates/stateful_widget_material_ticker.tmpl
//
// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
// of samples, and may be ignored if you are just exploring the sample.

// Flutter code sample for DecoratedBoxTransition
//
//***************************************************************************
//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)

// The following code implements the [DecoratedBoxTransition] as seen in the video
// above:

//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
//***************************************************************************

import 'package:flutter/material.dart';

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

/// This is the main application widget.
class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

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

/// This is the stateful widget that the main application instantiates.
class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

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

/// This is the private State class that goes with MyStatefulWidget.
/// AnimationControllers can be created with `vsync: this` because of TickerProviderStateMixin.
class _MyStatefulWidgetState extends State<MyStatefulWidget>
    with TickerProviderStateMixin {
//********************************************************************
//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)

  final DecorationTween decorationTween = DecorationTween(
    begin: BoxDecoration(
      color: const Color(0xFFFFFFFF),
      border: Border.all(style: BorderStyle.none),
      borderRadius: BorderRadius.circular(60.0),
      shape: BoxShape.rectangle,
      boxShadow: const <BoxShadow>[
        BoxShadow(
          color: Color(0x66666666),
          blurRadius: 10.0,
          spreadRadius: 3.0,
          offset: Offset(0, 6.0),
        )
      ],
    ),
    end: BoxDecoration(
      color: const Color(0xFFFFFFFF),
      border: Border.all(
        style: BorderStyle.none,
      ),
      borderRadius: BorderRadius.zero,
      // No shadow.
    ),
  );

  late final AnimationController _controller = AnimationController(
    vsync: this,
    duration: const Duration(seconds: 3),
  )..repeat(reverse: true);

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

  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.white,
      child: Center(
        child: DecoratedBoxTransition(
          position: DecorationPosition.background,
          decoration: decorationTween.animate(_controller),
          child: Container(
            width: 200,
            height: 200,
            padding: const EdgeInsets.all(10),
            child: const FlutterLogo(),
          ),
        ),
      ),
    );
  }

//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
//********************************************************************

}