android - 当条件成立时，Flutter 重定向到新屏幕

Question

我有一个像这样的 flutter 应用程序

main.dart

import 'package:flutter/material.dart';
import 'network.dart';

void main() => runApp(HomePage());

class HomePage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _MyAppState();
  }
}


class _MyAppState extends State<HomePage> {
  String _message = '';
  final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();

  _register() {
    _firebaseMessaging.getToken().then((token) => print(token));
  }

  @override
  void initState() {
    super.initState();
    getMessage();

    TestNetwork.checkNetwork().then((val){
          print(val);
    });
  }

  void getMessage(){
    _firebaseMessaging.configure(
        onMessage: (Map<String, dynamic> message) async {
      print('on message $message');
      setState(() => _message = message["notification"]["title"]);
    }, onResume: (Map<String, dynamic> message) async {
      print('on resume $message');
      setState(() => _message = message["notification"]["title"]);
    }, onLaunch: (Map<String, dynamic> message) async {
      print('on launch $message');
      setState(() => _message = message["notification"]["title"]);
    });
  }

  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return new MaterialApp(

        home: new Scaffold(
          body: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text("Message: $_message"),
            OutlineButton(
              child: Text("Register My Devices"),
              onPressed: () {
                _register();
              },
            )

          ]),
        ),
      );

  }
}

我正在从另一个 dart 文件调用网络检查功能，所以

网络.dart

import 'package:http/http.dart' as http;
import 'dart:async';

class TestNetwork {

static String mainWebServiceURL="http://mydmain.com/webservicepath/";

static Future<bool> checkNetwork() async {
  try{
      Map<String,String> _user = {};
      _user['name'] = "Username";
      final response= await http.post(mainWebServiceURL+'/index.php',
        body: _user,
      );
      if(response.statusCode==200)
        return Future.value(true);
        else
        // I want to redierct to another page in main.dart page
  }
  catch (_) {
    // I want to redierct to another page in main.dart page
  }

}

}

所以我的问题是，如果 checkNetwork() 函数失败或响应为“否定”，那么我想重定向/显示 main.dart 或另一个页面中的另一个页面。

Answer 1

(注意:将以下代码包装在零时间延迟的 future 中只是为了确保当我们使用它时上下文已准备好)

 @override
  void initState() {
    super.initState();
    getMessage();

   Future.delayed(Duration.zero,(){
     TestNetwork.checkNetwork().then((val){
       Navigator.of(context).push(MaterialPageRoute(builder: (ctx)=>MySuccessRoute()));
     },onError: (){
       Navigator.of(context).push(MaterialPageRoute(builder: (ctx)=>MyFailureRoute()));
     });
   });
  }