Flutter中Firebase signInWithCredential社交登录返回phoneNumber为null问题

问题重现 #

Firebase返回的用户信息示例：

{"additionalUserInfo": {"isNewUser": true,"user": {"displayName":"i set it private","email":"i set it private","phoneNumber":null,"photoURL":"i set it private"}}

测试用Google登录代码：

void googleSingIn() async {
  emit(GoogleAuthLoadingState());
  if (await checkConnectivity() == AppConstants.connectivityWifi ||
      await checkConnectivity() == AppConstants.connectivitymobile) {
    try {
      // Trigger the authentication flow
      final GoogleSignIn googleSignIn = GoogleSignIn();
      final GoogleSignInAccount? googleSignInAccount =
          await googleSignIn.signIn();

      if (googleSignInAccount == null) {
        return;
      }

      // Obtain the auth details from the request
      final GoogleSignInAuthentication googleAuth =
          await googleSignInAccount.authentication;

      // Create a new credential
      final credential = GoogleAuthProvider.credential(
          accessToken: googleAuth.accessToken, idToken: googleAuth.idToken);

      // Once signed in, return the UserCredential
      final userCredential =
          await FirebaseAuth.instance.signInWithCredential(credential);

      final googleUser = userCredential.user;
      final additionalUserInfo = userCredential.additionalUserInfo;
      dev.log("$userCredential");

      if (additionalUserInfo!.isNewUser == false) {
        login(
          email: googleUser!.email!,
          password: googleUser.uid,
          method: AppConstants.googleMethod,
        );
      } else {
        RouteGenerator.registerCubit.register(
          google: googleUser!.email,
          googlePassword: googleUser.uid,
          firstName: additionalUserInfo.profile?["given_name"],
          lastName: additionalUserInfo.profile?["family_name"],
          image: googleUser.photoURL,
        );
      }
    } catch (e) {
      emit(GoogleAuthErrorState(error: e.toString()));
    }
  } else {
    emit(LogInConnectivity(
        connectivityMessage: StringsManager.connectionError));
  }
}

核心原因 #

Google、Facebook、Apple等平台默认不会将用户手机号共享给第三方应用，Firebase无法直接从登录凭证中获取该字段，必须主动请求对应权限并通过平台特定API获取。

分平台解决方案 #

Google登录

1. 请求手机号权限
   修改GoogleSignIn初始化代码，添加手机号相关scope：

   final GoogleSignIn googleSignIn = GoogleSignIn(
     scopes: [
       'email',
       'profile',
       'https://www.googleapis.com/auth/userinfo.phone' // 添加该scope请求手机号权限
     ],
   );
   

2. 通过People API获取手机号
   先在Google Cloud控制台启用People API，再用登录返回的accessToken调用API：

   // 获取googleAuth后执行
   final http.Response response = await http.get(
     Uri.parse('https://people.googleapis.com/v1/people/me?personFields=phoneNumbers'),
     headers: {'Authorization': 'Bearer ${googleAuth.accessToken}'},
   );
   
   if (response.statusCode == 200) {
     final data = jsonDecode(response.body);
     final phoneNumbers = data['phoneNumbers'] as List?;
     if (phoneNumbers != null && phoneNumbers.isNotEmpty) {
       final phoneNumber = phoneNumbers[0]['value'];
       // 可选择将手机号存入自有数据库，或通过Firebase的updatePhoneNumber方法更新用户字段（需完成手机号验证流程）
     }
   }
   

   注意：用户可能未绑定手机号或拒绝授权，需处理空值情况。

Facebook登录

1. 后台配置权限
   在Facebook开发者后台，为应用添加public_profile、email、user_phone_number权限。

2. 登录时请求权限

   final LoginResult result = await FacebookAuth.instance.login(
     permissions: ['public_profile', 'email', 'user_phone_number'],
   );
   

3. 提取手机号

   final userData = await FacebookAuth.instance.getUserData(
     fields: 'name,email,phone',
   );
   final phoneNumber = userData['phone'];
   // 后续处理同Google登录
   

   注意：user_phone_number权限需通过Facebook应用审核后，才能面向非测试用户开放。

Apple登录

Apple登录仅在首次登录且用户同意共享手机号时，可通过凭证解析获取手机号，后续登录无法再获取，需自行存储：

final credential = await SignInWithApple.getAppleIDCredential(
  scopes: [
    AppleIDAuthorizationScopes.email,
    AppleIDAuthorizationScopes.fullName,
  ],
);

需通过后端服务调用Apple官方验证接口，解析credential.authorizationCode或identityToken提取手机号，前端无法直接解析。

通用注意事项 #

• Firebase Auth的user.phoneNumber字段仅在手机号验证码登录，或主动调用updatePhoneNumber并完成验证后才会被设置，社交登录不会自动填充。
• 所有平台的手机号权限需符合平台政策，部分权限需提交审核才能全面开放。
• 必须处理用户拒绝授权或未绑定手机号的情况，避免空值引发崩溃。

内容的提问来源于stack exchange，提问作者Ahmed Hussein