gistfile1.txt

import 'package:flutter/material.dart';
import 'package:flutter_swiper/flutter_swiper.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  var _index = 1;
  SwiperController controller = SwiperController();

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
        body: Container(
      child: Carousel(
        height: 300,
      ),
    ) // This trailing comma makes auto-formatting nicer for build methods.
        );
  }
}

class Carousel extends StatefulWidget {
  final List<Widget> items;
  final double dividerIndent;
  final Function(BuildContext context, dynamic item) builderFunction;

  final double height;

  Carousel({
    Key key,
    @required this.items,
    @required this.builderFunction,
    @required this.height,
    this.dividerIndent = 10,
  }) : super(key: key);

  @override
  State<StatefulWidget> createState() {
    return _CarouselState();
  }
}

class _CarouselState extends State<Carousel> {
  static double fraction = 0.45;

  PageController _pageController =
      PageController(viewportFraction: fraction, initialPage: 0);

  double _selected = 0;

  @override
  void initState() {
    super.initState();
    _pageController.addListener(() {
      setState(() {
        _selected = _pageController.page;
      });
    });
  }

  double checkPadding(double actualPage, int page) {
    print('$actualPage $page');
    double r = actualPage - page;
    if (r == 0) {
      return 0;
    }

    if (r > 0 && r < 1) {
      return 50 * r;
    }

    if (r < 0 && r > -1) {
      return 50 * r.abs();
    }

    return 50;
  }

  @override
  Widget build(BuildContext context) {
    return Container(
        height: widget.height,
        child: ListView(
          controller: _pageController,
          physics: PageScrollPhysics(),
          scrollDirection: Axis.horizontal,
          children: [
            AnimatedContainer(
              margin: EdgeInsets.only(bottom: checkPadding(_selected, 0)),
              color: Colors.red,
              width: MediaQuery.of(context).size.width * fraction,
              duration: Duration(milliseconds: 100),
            ),
            AnimatedContainer(
                margin: EdgeInsets.only(bottom: checkPadding(_selected, 1)),
                color: Colors.brown,
                width: MediaQuery.of(context).size.width * fraction,
                duration: Duration(milliseconds: 100)),
            InkWell(
              onTap: () => setState(() {
                _pageController.animateToPage(2,
                    duration: Duration(seconds: 1), curve: Curves.ease);
              }),
              child: AnimatedContainer(
                  margin: EdgeInsets.only(bottom: checkPadding(_selected, 2)),
                  color: Colors.orange,
                  width: MediaQuery.of(context).size.width * fraction,
                  duration: Duration(milliseconds: 100)),
            ),
            Container(
              width: MediaQuery.of(context).size.width * 0.7,
            )
          ],
        ));
  }
}