放到ListView中，swiper自动回到第一个！

[clong1995]

1、放到ListView中，把swiper滑动到非首个。
2、把ListView滑动到底部。
3、然后把ListView滑到顶部查看swiper。
现象：swiper自动回到第一个！
期望：保持swiper用户滑动的位置。

import 'package:flutter/material.dart';

import 'package:flutter_swiper/flutter_swiper.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

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

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body:  ListView(
        children: <Widget>[
          Container(
            width: double.infinity,
            height: 400,
            decoration: BoxDecoration(
              color: Colors.green,
            ),
            child: new Swiper(
              itemBuilder: (BuildContext context,int index){
                return new Image.network("http://via.placeholder.com/350x150",fit: BoxFit.fill,);
              },
              itemCount: 3,
              pagination: new SwiperPagination(),
              control: new SwiperControl(),
            ),
          ),
          Container(
            width: double.infinity,
            height: 1500,
            decoration: BoxDecoration(
              color: Colors.blue,
            ),
          ),
        ],
      )
    );
  }
}