如何在Flutter中维护TabBarView中的页面状态？

class TabBarViewPage extends StatefulWidget {
  @override
  _TabBarViewPageState createState() => _TabBarViewPageState();
}

class _TabBarViewPageState extends State<TabBarViewPage> {
  int _currentIndex = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('TabBarView Example'),
      ),
      body: Column(
        children: [
          TabBar(
            tabs: [
              Tab(text: 'Tab 1'),
              Tab(text: 'Tab 2'),
              Tab(text: 'Tab 3'),
            ],
            onTap: (index) {
              setState(() {
                _currentIndex = index;
              });
            },
          ),
          Expanded(
            child: TabBarView(
              children: [
                Page1(),
                Page2(),
                Page3(),
              ],
              controller: TabController(
                length: 3,
                initialIndex: _currentIndex,
                vsync: this,
              ),
            ),
          ),
        ],
      ),
    );
  }
}