Flutter -如何用按钮刷新PageView中的页面？

import 'package:flutter/material.dart';

class MyPage extends StatefulWidget {
  @override
  _MyPageState createState() => _MyPageState();
}

class _MyPageState extends State<MyPage> {
  int currentPage = 0;
  PageController _pageController;

  @override
  void initState() {
    super.initState();
    _pageController = PageController(initialPage: currentPage);
  }

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

  void refreshPage() {
    setState(() {
      currentPage += 1;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('PageView Refresh'),
      ),
      body: Column(
        children: [
          Expanded(
            child: PageView(
              controller: _pageController,
              children: [
                Container(
                  color: Colors.red,
                  child: Center(
                    child: Text('Page 1'),
                  ),
                ),
                Container(
                  color: Colors.blue,
                  child: Center(
                    child: Text('Page 2'),
                  ),
                ),
                Container(
                  color: Colors.green,
                  child: Center(
                    child: Text('Page 3'),
                  ),
                ),
              ],
            ),
          ),
          RaisedButton(
            child: Text('Refresh'),
            onPressed: refreshPage,
          ),
        ],
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: MyPage(),
  ));
}