最常见的情况是，如果您正在运行动画并且不想在后台消耗资源。在这种情况下，你应该延长您的State使用TickerProviderStateMixin，并使用你的State作为vsync的说法AnimationController。当您State可见时，Flutter 只会处理动画控制器的侦听器。

如果你想State住在你的S PageRoute当被置于PageRoute被其他内容遮挡，可以传递的参数，以您的构造函数。如果执行此操作，则隐藏时将重置自身（及其子代），并且必须使用作为 其构造函数参数传入的属性来 重新构造自身。如果您不希望 完全重置 ，则可以使用模型或控制器类或来保存用户的进度信息。
maintainState
falsePageRoute
State
initState
widget
PageStorage

这是一个演示这些概念的示例应用程序。

import 'package:flutter/material.dart';

void main() {
  runApp(new MaterialApp(
    onGenerateRoute: (RouteSettings settings) {
      if (settings.name == '/') {
        return new MaterialPageRoute<Null>(
          settings: settings,
          builder: (_) => new MyApp(),
          maintainState: false,
        );
      }
      return null;
    }
  ));
}

class MyApp extends StatefulWidget {
  MyAppState createState() => new MyAppState();
}

class MyAppState extends State<MyApp> with TickerProviderStateMixin {
  AnimationController _controller;

  @override
  void initState() {
    print("initState was called");
    _controller = new AnimationController(vsync: this)
      ..repeat(min: 0.0, max: 1.0, period: const Duration(seconds: 1))
      ..addListener(() {
        print('animation value ${_controller.value}');
      });
    super.initState();
  }

  @override
  void dispose() {
    print("dispose was called");
    _controller.dispose();
    super.dispose();
  }

  int _counter = 0;

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('home screen')
      ),
      body: new Center(
        child: new RaisedButton(
          onPressed: () {
            setState(() {
              _counter++;
            });
          },
          child: new Text('Button pressed $_counter times'),
        ),
      ),
      floatingActionButton: new FloatingActionButton(
        child: new Icon(Icons.remove_red_eye),
        onPressed: () {
          Navigator.push(context, new MaterialPageRoute(
            builder: (BuildContext context) {
              return new MySecondPage(counter: _counter);
            },
          ));
        },
      ),
    );
  }
}

class MySecondPage extends StatelessWidget {
  MySecondPage({ this.counter });

  final int counter;

  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Certificate of achievement'),
      ),
      body: new Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: [
          new Icon(Icons.developer_mode, size: 200.0),
          new Text(
            'Congrats, you clicked $counter times.',
            style: Theme.of(context).textTheme.title,
            textAlign: TextAlign.center,
          ),
          new Text(
            'All your progress has now been lost.',
            style: Theme.of(context).textTheme.subhead,
            textAlign: TextAlign.center,
          ),
        ],
      ),
    );
  }
}