/*
 * @Author: 一凨 
 * @Date: 2018-12-15 20:39:14 
 * @Last Modified by: 一凨
 * @Last Modified time: 2018-12-15 21:27:39
 */
import 'package:flutter/material.dart';

class ScrollPhysicsDemo extends StatefulWidget {
  _ScrollPhysicsDemoState createState() => _ScrollPhysicsDemoState();
}

class _ScrollPhysicsDemoState extends State<ScrollPhysicsDemo> {
  final PageController _pageController =  PageController();
  double _currentPage = 0.0;

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 300.0,
      width: MediaQuery.of(context).size.width,
      child: LayoutBuilder(
        builder: (context, constraints) => NotificationListener(
              onNotification: (ScrollNotification note) {
                setState(() {
                  _currentPage = _pageController.page;
                });
              },
              child: PageView.custom(
                physics: const PageScrollPhysics(
                    parent: const BouncingScrollPhysics()),
                controller: _pageController,
                childrenDelegate: SliverChildBuilderDelegate(
                  (context, index) => _SimplePage(
                        '$index',
                        parallaxOffset:
                            constraints.maxWidth / 2.0 * (index - _currentPage),
                        // 小字 Text 在页面滑动时要比整体移动速度快一倍，所以小字的 translate X 为 \tt{pageWidth / 2 * progress} 。
                      ),
                  childCount: 10,
                ),
              ),
            ),
      ),
    );
  }
}

class _SimplePage extends StatelessWidget {
  _SimplePage(this.data, {Key key, this.parallaxOffset = 0.0})
      : super(key: key);

  final String data;
  final double parallaxOffset;

  @override
  Widget build(BuildContext context) =>  Center(
        child: Container(
          color: Theme.of(context).primaryColor,
          child:  Center(
            child:  Column(
              mainAxisSize: MainAxisSize.min,
              children: <Widget>[
                 Text(
                  data,
                  style: const TextStyle(fontSize: 60.0,color: Colors.white),
                ),
                 SizedBox(height: 40.0),
                 Transform(
                  transform:
                       Matrix4.translationValues(parallaxOffset, 0.0, 0.0),
                  child: const Text('左右滑动，这是第二行滚动速度更快的小字',style: const TextStyle(fontSize: 16.0,color: Colors.white),),
                ),
              ],
            ),
          ),
        ),
      );
}