Question

我在我的android应用中使用firebase作为后端服务。如果用户未登录，我试图将用户导航到登录屏幕。我正在检查 main.dart 文件中的身份验证状态。应用启动时，我在logcat窗口中看到了一些东西，

E/FirebaseInstanceId(10239): Failed to resolve target intent service, skipping classname enforcement
E/FirebaseInstanceId(10239): Error while delivering the message: ServiceIntent not found.

下面是我的代码：

main.dart

import 'package:firebase_auth/firebase_auth.dart';
import 'package:flutter/material.dart';
import 'package:google_sign_in/google_sign_in.dart';
import './home.dart';
import './orders.dart';
import './account.dart';
import './login.dart';

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

class MyApp extends StatelessWidget {

@override
Widget build(BuildContext context) {
return MaterialApp(
  home: MyTabs(),
  debugShowCheckedModeBanner: false,
  routes: <String,WidgetBuilder>{
    '/login':(BuildContext context) => Login()
  },
  theme: ThemeData(
    primaryColor: Colors.white,
    primaryColorDark: Colors.grey,
    accentColor: Colors.green
   ),
  );
 }
}

class MyTabs extends StatefulWidget {

@override
_MyTabsState createState() => _MyTabsState();
}


class _MyTabsState extends State<MyTabs> {

FirebaseAuth auth = FirebaseAuth.instance;

int selectedIndex = 0;
final pages = [Home(),Orders(),Account()];

void choosePage(int index){

setState(() {

    selectedIndex = index;
  });
}

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

  if(auth.currentUser() == null){

     Navigator.of(context).pushReplacementNamed("/login");
  }
}

 @override
 Widget build(BuildContext context) {
 return Scaffold(
     appBar: AppBar(
       title: Text("Tiffino")
     ),
     body: pages[selectedIndex],
     bottomNavigationBar: BottomNavigationBar(
      currentIndex: selectedIndex,
      fixedColor: Colors.black,
      onTap: choosePage,
      items: [
        BottomNavigationBarItem(
           icon: Icon(Icons.home),
           title: Text("Home")
        ),
        BottomNavigationBarItem(
           icon: Icon(Icons.list),
           title: Text("Orders")
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.person),
          title: Text("Account")
         )
        ]
      )      
    );
  }
}

如果我在上面的代码中做错了什么，请纠正我。

谢谢

Answer 1

auth.currentUser()方法返回一个Future，这意味着您应该使用then()方法或异步方法中的await运算符来解析它，而不是立即检查它是否为null。 ##标题##

尝试使用异步调用，而不是使用then和catchError，这将导致调用更多方法：

@override
void initState() {
    super.initState();
    _getCurrentUser();
}

/// Checks if the user is logged in
_getCurrentUser() async {
    //Notice here the await operator, instead of using then() etc.
    FirebaseUser mCurrentUser = await auth.currentUser();
    if(mCurrentUser != null){
      authSuccess(mCurrentUser);
    } else {
      // not logged in
      Navigator.of(context).pushReplacementNamed("/login");
    }
}

void authSuccess(FirebaseUser user){
    // User is logged in, do something if needed
}

无法根据flutter-firebase中的auth状态进行导航

1 个答案: