dart - Flutter - 使用 pushReplacementNamed 在路由之间传递值

Question

我正在尝试使用 Navigator.pushReplacementNamed() 在路由之间传递值，但我没有得到它。

我无法弄清楚数据将退出 pushReplacementNamed 并获取 routes 键的正确语法和逻辑是什么。

你能帮帮我吗？

输入下面的代码，方便理解:

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(),
      routes: <String, WidgetBuilder> {
        '/form': (BuildContext context) => new FormPage(email: ???, header: {'auth': ???}),
      },
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      floatingActionButton: new FloatingActionButton(
        onPressed: () {
          Navigator.pushReplacementNamed(context, '/form', {email: 'myemail@flutter.com', header: {'auth': '1234'}});
        },
        child: new Icon(Icons.navigate_next),
      ),
    );
  }
}

class FormPage extends StatefulWidget {
  FormPage({Key key, this.email, this.header}) : super(key: key);
  String email;
  Map header;
  @override
  FormPageState createState() => new FormPageState();
}

class FormPageState extends State<FormPage> {
  @override
  Widget build(BuildContext context) {
    return new Container(
      child: new Column(
        children: <Widget>[
          new Text(widget.email),
          new Text(widget.header['auth'])
        ],
      ),
    );
  }
}

修正后:

尝试使用 pushReplacementNamed 的目的是删除路线历史记录，因此如果用户按下设备的后退按钮返回到较早的路线，则该路线将不再存在。 Reference

这个实现的原因是在登录页面上使用，如果用户已经通过 google sign 的身份验证，他将被重定向到下一个传递登录参数的页面，并且无法返回到通过设备的后退按钮登录页面。

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(),
      routes: <String, WidgetBuilder> {
        '/form': (BuildContext context) => new FormPage(), //new
      },
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      floatingActionButton: new FloatingActionButton(
        onPressed: () {
          Navigator.of(context).pushReplacement(                                                         //new
            new MaterialPageRoute(                                                                       //new
              settings: const RouteSettings(name: '/form'),                                              //new
              builder: (context) => new FormPage(email: 'myemail@flutter.com', header: {'auth': '1234'}) //new
            )                                                                                            //new
          );                                                                                             //new
        },
        child: new Icon(Icons.navigate_next),
      ),
    );
  }
}

class FormPage extends StatefulWidget {
  FormPage({Key key, this.email, this.header}) : super(key: key);
  String email;
  Map header;
  @override
  FormPageState createState() => new FormPageState();
}

class FormPageState extends State<FormPage> {
  @override
  Widget build(BuildContext context) {
    return new Container(
      child: new Column(
        children: <Widget>[
          new Text(widget.email),
          new Text(widget.header['auth'])
        ],
      ),
    );
  }
}

Answer 1

我认为您可能不了解 result 的工作原理。结果返回到推送最后一条路线的前一个小部件，并使用 await 作为 Future 的结果，该 Future 由之前调用 push。你只是想用参数开始一条路线吗？然后你可以这样做。

Navigator.of(context).pushReplacement(
  new MaterialPageRoute(
    settings: const RouteSettings(name: '/form'),
    builder: (context) => new FormPage(
      email: 'myemail@flutter.com',
      header: {'auth': '1234'},
    ),
  ),
);