flutter - 在没有上下文的情况下导航

Question

我创建了一个服务文件夹并在其中创建了一个名为 request.txt 的文件。 dart，在这里我打算将我提出的所有请求放入一个名为 AuthService 的类中，下面的登录请求我希望能够在 response.statusCode == 200 或 201 后导航到主屏幕，但我无法这样做，因为导航需要上下文，我的类既不是有状态也不是无状态小部件，有什么方法可以在没有上下文的情况下导航？

import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
import 'package:flutter/material.dart';

class AuthService {

  login(email, password) async {
    SharedPreferences sharedPreferences = await SharedPreferences.getInstance();

    if (email == "" && password == "") {
      return;
    }

    try {
      Map data = {'email': email, 'password': password};

      var jsonResponse;
      var response = await http
          .post('https://imyLink.com/authenticate', body: data);
      if (response.statusCode == 200 || response.statusCode == 201) {

//I want to navigate to my home screen once the request made is successful

        jsonResponse = json.decode(response.body);
        if (jsonResponse != null) {
          await sharedPreferences.setString("userToken", jsonResponse["token"]);
          var token = sharedPreferences.getString("userToken");
          print('Token: $token');
          print(jsonResponse);
          print("Login successful");
        }
      } else {
        print(response.statusCode);
        print('Login Unsuccessful');
        print(response.body);
      }
    } catch (e) {
      print(e);
    }
}

Answer 1

首先，创建一个类

import 'package:flutter/material.dart';

class NavigationService{
  GlobalKey<NavigatorState> navigationKey;

  static NavigationService instance = NavigationService();

   NavigationService(){
     navigationKey = GlobalKey<NavigatorState>();
   }

  Future<dynamic> navigateToReplacement(String _rn){
return navigationKey.currentState.pushReplacementNamed(_rn);
  }
 Future<dynamic> navigateTo(String _rn){
   return navigationKey.currentState.pushNamed(_rn);
  }
 Future<dynamic> navigateToRoute(MaterialPageRoute _rn){
   return navigationKey.currentState.push(_rn);
  }

 goback(){
   return navigationKey.currentState.pop();

  }
  }

在您的 main.dart 文件中。

 MaterialApp(
  navigatorKey: NavigationService.instance.navigationKey,
  initialRoute: "login",
  routes: {
    "login":(BuildContext context) =>Login(),
    "register":(BuildContext context) =>Register(),
    "home":(BuildContext context) => Home(),

  },
);

然后您可以从项目中的任何位置调用该函数，例如...

 NavigationService.instance.navigateToReplacement("home");
 NavigationService.instance.navigateTo("home");