examples/api/lib/widgets/implicit_animations/animated_padding.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 AnimatedPadding

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

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

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

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

class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  double padValue = 0.0;
  void _updatePadding(double value) {
    setState(() {
      padValue = value;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        AnimatedPadding(
          padding: EdgeInsets.all(padValue),
          duration: const Duration(seconds: 2),
          curve: Curves.easeInOut,
          child: Container(
            width: MediaQuery.of(context).size.width,
            height: MediaQuery.of(context).size.height / 5,
            color: Colors.blue,
          ),
        ),
        Text('Padding: $padValue'),
        ElevatedButton(
            child: const Text('Change padding'),
            onPressed: () {
              _updatePadding(padValue == 0.0 ? 100.0 : 0.0);
            }),
      ],
    );
  }
}