iOS集成Google登录遇GIDSignIn表达式歧义错误，求解决

我按照教程为iOS应用集成Google登录，其余功能正常，但在LoginVM.swift的以下代码行：

GIDSignIn.sharedInstance.signIn(with: config, presenting:ApplicationUtility.rootViewController) {

出现错误提示：Type of expression is ambiguous without more context

完整代码 #

//
//  LoginVM.swift
//  frcscout
//
//  Created by Elliot Scher on 12/14/22.
//

import Foundation
import Firebase
import GoogleSignIn

class SignUpViewModel: ObservableObject {
    
    @Published var isLogin: Bool = false
    
    func signInWithGoogle() {
                
        guard let clientId = FirebaseApp.app()?.options.clientID else { return }
        
        let config = GIDConfiguration(clientID: clientId)
        
        GIDSignIn.sharedInstance.signIn(with: config, presenting:ApplicationUtility.rootViewController) {
            [self] user, err in
            
            if let error = err {
                print(error.localizedDescription)
                return
            }
            
            guard
                let authentication = user.authentication,
                let idToken = authentication.idToken
            else { return }
            
            let credential = GoogleAuthProvider.credential(withIDToken: idToken, accessToken: authentication.accessToken)
            
            Auth.auth().signIn(with: credential) { result, error in
                if let error = err {
                    print(error.localizedDescription)
                    return
                }
                
                guard let user = result?.user else { return }
                print(user.displayName)
                isLogin.toggle()
            }
                    
        }
        
    }
}

解决方案 #

• 确保presenting参数类型匹配
  编译器无法识别ApplicationUtility.rootViewController的类型，signIn方法要求presenting参数为UIViewController类型。如果rootViewController是可选类型，需先解包：

  guard let rootVC = ApplicationUtility.rootViewController else { 
      print("无法获取根视图控制器")
      return 
  }
  GIDSignIn.sharedInstance.signIn(with: config, presenting: rootVC) {
      // 后续闭包代码
  }
  

• 检查GoogleSignIn SDK版本
  不同版本的SDK方法签名可能存在差异，确认GIDSignIn.sharedInstance.signIn的官方文档，确保参数和回调闭包的格式与当前版本匹配。

• 修复闭包内变量错误
  在Firebase登录的闭包中，错误地使用了外部的err变量而非当前闭包的error参数，这会导致逻辑错误，需修正：

  Auth.auth().signIn(with: credential) { result, error in
      if let error = error { // 将err改为error
          print(error.localizedDescription)
          return
      }
      // 后续代码
  }
  

内容的提问来源于stack exchange，提问作者user17792511