iOS应用Google Sign In流程中断报错（Code-4/-5）求助

问题描述 #

开发iOS应用集成Google Sign In，编译正常，但点击登录按钮后，授权弹窗几秒后自动消失，报错：

This is the error: Optional("The operation couldn’t be completed. (com.google.GIDSignIn error -4.)")
error with signing in: Optional(Error Domain=com.google.GIDSignIn Code=-5 "The user canceled the sign-in flow." UserInfo={NSLocalizedDescription=The user canceled the sign-in flow.})

错误码解析 #

• Error -4: 钥匙链访问错误，通常是应用没有正确的钥匙链权限，或者Client ID配置不匹配
• Error -5: 表面显示用户取消，但实际是登录流程因底层错误（如-4）被强制终止，并非用户主动操作

解决方案 #

1. 检查Google Cloud控制台配置 #

• 确认使用的是iOS类型的Client ID，而非Web或Android类型
• 验证控制台中填写的Bundle ID与Xcode项目的Bundle Identifier完全一致（大小写敏感）
• 确保已在控制台启用Google Sign In API
• 检查Redirect URI格式是否正确：com.googleusercontent.apps.{你的Client ID}:/oauth2redirect

2. Xcode项目配置修复 #

• 添加URL Scheme：在Info.plist中添加CFBundleURLTypes数组，其中CFBundleURLSchemes包含你的Google Client ID的反向ID（即com.googleusercontent.apps.xxxxxxxxx，可从控制台复制）
• 添加查询Scheme：在Info.plist中添加LSApplicationQueriesSchemes数组，包含以下项：

  <string>google</string>
  <string>googleusercontent</string>
  

• 启用Keychain Sharing：进入项目Target -> Signing & Capabilities -> 点击+ Capability，添加Keychain Sharing，并添加团队ID前缀+Bundle ID的组（例如TEAMID.com.yourcompany.appname）

3. 代码逻辑优化 #

当前代码在viewDidLoad和signInPressed中重复调用googleSignIn，导致登录流程冲突，建议调整：

修改signInPressed方法

@IBAction func signInPressed(_ sender: UIButton) {
    print("Sign in pressed")
    
    let user = GIDSignIn.sharedInstance.currentUser
    if user == nil {
        // 直接发起新登录，跳过restore流程
        let signInConfig = GIDConfiguration(clientID: K.clientID)
        GIDSignIn.sharedInstance.signIn(with: signInConfig, presenting: self) { gUser, signInError in
            if signInError == nil {
                guard let gUser = gUser else {
                    sender.setTitle("Sign in", for: .normal)
                    return
                }
                self.requestScopes(googleUser: gUser) { success in
                    sender.setTitle(success ? "Sign out" : "Sign in", for: .normal)
                }
            } else {
                print("error with signing in: \(String(describing: signInError)) ")
                self.service.authorizer = nil
                sender.setTitle("Sign in", for: .normal)
            }
        }
    } else {
        GIDSignIn.sharedInstance.signOut()
        self.service.authorizer = nil
        sender.setTitle("Sign in", for: .normal)
    }
}

调整googleSignIn方法（仅用于恢复登录）

func googleSignIn(completionHandler: @escaping (Bool) -> Void) {
    GIDSignIn.sharedInstance.restorePreviousSignIn { user, error in
        if let user = user {
            print("Managed to restore previous sign in!\nScopes: \(String(describing: user.grantedScopes))")
            self.requestScopes(googleUser: user) { success in
                completionHandler(success)
            }
        } else {
            print("No previous user!\nThis is the error: \(String(describing: error?.localizedDescription))")
            completionHandler(false)
        }
    }
}

修复requestScopes中的认证逻辑

替换错误的user?.authentication.do写法：

func requestScopes(googleUser: GIDGoogleUser, completionHandler: @escaping (Bool) -> Void) {
    let grantedScopes = googleUser.grantedScopes
    if grantedScopes == nil || !grantedScopes!.contains(K.grantedScopes) {
        let additionalScopes = K.additionalScopes
        GIDSignIn.sharedInstance.addScopes(additionalScopes, presenting: self) { user, scopeError in
            if scopeError == nil, let user = user {
                // 正确获取认证信息
                if let authentication = user.authentication {
                    let authorizer = authentication.fetcherAuthorizer()
                    self.service.authorizer = authorizer
                    completionHandler(true)
                } else {
                    print("Failed to get authentication")
                    completionHandler(false)
                }
            } else {
                completionHandler(false)
                print("Error with adding scopes: \(String(describing: scopeError?.localizedDescription))")
            }
        }
    } else {
        print("Already contains the scopes!")
        // 直接设置授权器
        if let authentication = googleUser.authentication {
            self.service.authorizer = authentication.fetcherAuthorizer()
        }
        completionHandler(true)
    }
}

4. 模拟器测试注意事项 #

• 确保模拟器已登录Google账号（设置 -> 密码与账户 -> 添加Google账户）
• 若仍有问题，尝试使用真机测试，模拟器的钥匙链权限有时会有异常

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