En la pestaña Sign in method, habilita el método de acceso con Google y haz clic en Guardar.
Cuando se te solicite en la consola, descarga el archivo de configuración de Firebase actualizado
(google-services.json), que ahora contiene la información del cliente de OAuth
necesaria para el acceso con Google.
Mueve este archivo de configuración actualizado a tu proyecto de Android Studio. Para ello, reemplaza
el archivo de configuración correspondiente
(consulta Agrega Firebase a tu proyecto de Android).
Accede a la clase firebase::auth::Auth
La clase Auth es la puerta de enlace para todas las llamadas a la API.
Agrega los archivos de encabezados de autenticación y de app:
#include"firebase/app.h"#include"firebase/auth.h"
En tu código de inicialización, crea una clase firebase::App.
Sigue las instrucciones para
iOS+
y Android
a fin de obtener un token de ID para el Acceso con Google.
Una vez que el usuario accede correctamente, intercambia el token de ID por una credencial
de Firebase y úsala para realizar la autenticación en Firebase:
Si el programa tiene un bucle de actualización que se ejecuta con regularidad (por ejemplo, 30 o 60 veces por segundo), puedes verificar los resultados una vez por actualización con Auth::SignInAndRetrieveDataWithCredentialLastResult:
firebase::Future<firebase::auth::AuthResult>result=auth->SignInAndRetrieveDataWithCredentialLastResult();if(result.status()==firebase::kFutureStatusComplete){if(result.error()==firebase::auth::kAuthErrorNone){firebase::auth::AuthResultauth_result=*result.result();printf("Sign in succeeded for `%s`\n",auth_result.user.display_name().c_str());}else{printf("Sign in failed with error '%s'\n",result.error_message());}}
Algunos programas tienen funciones Update que se llaman 30 o 60 veces por segundo.
Por ejemplo, muchos juegos siguen este modelo. Estos programas pueden llamar a las funciones LastResult para sondear las llamadas asíncronas.
Sin embargo, si tu programa es controlado por eventos, tal vez sea mejor que registres funciones de devolución de llamada.
Se solicita una función de devolución de llamada una vez que se complete Future.
voidOnCreateCallback(constfirebase::Future<firebase::auth::User*>&result,void*user_data){// The callback is called when the Future enters the `complete` state.assert(result.status()==firebase::kFutureStatusComplete);// Use `user_data` to pass-in program context, if you like.MyProgramContext*program_context=static_cast<MyProgramContext*>(user_data);// Important to handle both success and failure situations.if(result.error()==firebase::auth::kAuthErrorNone){firebase::auth::User*user=*result.result();printf("Create user succeeded for email %s\n",user->email().c_str());// Perform other actions on User, if you like.firebase::auth::User::UserProfileprofile;profile.display_name=program_context->display_name;user->UpdateUserProfile(profile);}else{printf("Created user failed with error '%s'\n",result.error_message());}}voidCreateUser(firebase::auth::Auth*auth){// Callbacks work the same for any firebase::Future.firebase::Future<firebase::auth::AuthResult>result=auth->CreateUserWithEmailAndPasswordLastResult();// `&my_program_context` is passed verbatim to OnCreateCallback().result.OnCompletion(OnCreateCallback,&my_program_context);}
La función de devolución de llamada también puede ser lambda, si así lo prefieres.
voidCreateUserUsingLambda(firebase::auth::Auth*auth){// Callbacks work the same for any firebase::Future.firebase::Future<firebase::auth::AuthResult>result=auth->CreateUserWithEmailAndPasswordLastResult();// The lambda has the same signature as the callback function.result.OnCompletion([](constfirebase::Future<firebase::auth::User*>&result,void*user_data){// `user_data` is the same as &my_program_context, below.// Note that we can't capture this value in the [] because std::function// is not supported by our minimum compiler spec (which is pre C++11).MyProgramContext*program_context=static_cast<MyProgramContext*>(user_data);// Process create user result...(void)program_context;},&my_program_context);}
Próximos pasos
Cuando un usuario accede por primera vez, se crea una cuenta de usuario nueva y se la vincula con las credenciales (el nombre de usuario y la contraseña, el número de teléfono o la información del proveedor de autenticación) que el usuario utilizó para acceder. Esta cuenta nueva se almacena como parte de tu proyecto de Firebase y se puede usar para identificar a un usuario en todas las apps del proyecto, sin importar cómo acceda.
En tus apps, puedes obtener la información básica de perfil del usuario a partir del objeto firebase::auth::User.
firebase::auth::Useruser=auth->current_user();if(user.is_valid()){std::stringname=user.display_name();std::stringemail=user.email();std::stringphoto_url=user.photo_url();// The user's ID, unique to the Firebase project.// Do NOT use this value to authenticate with your backend server,// if you have one. Use firebase::auth::User::Token() instead.std::stringuid=user.uid();}
En tus
Reglas de seguridad de Firebase Realtime Database y Cloud Storage, puedes
obtener el ID del usuario único que accedió a partir de la variable auth
y usarlo para controlar a qué datos podrá acceder.
[[["Fácil de comprender","easyToUnderstand","thumb-up"],["Resolvió mi problema","solvedMyProblem","thumb-up"],["Otro","otherUp","thumb-up"]],[["Falta la información que necesito","missingTheInformationINeed","thumb-down"],["Muy complicado o demasiados pasos","tooComplicatedTooManySteps","thumb-down"],["Desactualizado","outOfDate","thumb-down"],["Problema de traducción","translationIssue","thumb-down"],["Problema con las muestras o los códigos","samplesCodeIssue","thumb-down"],["Otro","otherDown","thumb-down"]],["Última actualización: 2025-08-16 (UTC)"],[],[],null,["You can let your users authenticate with Firebase using their Google Accounts by\nintegrating Google Sign-In into your app.\n\nBefore you begin\n\n1. [Add Firebase to your C++ project](/docs/cpp/setup#note_select_platform).\n2. Enable Google as a sign-in method in the Firebase console:\n 1. In the [Firebase console](//console.firebase.google.com/), open the **Auth** section.\n 2. On the **Sign in method** tab, enable the **Google** sign-in method and click **Save**.\n3. When prompted in the console, download the updated Firebase config file (`google-services.json`), which now contains the OAuth client information required for Google sign-in.\n4. Move this updated config file into your Android Studio project, *replacing* the now-outdated corresponding config file. (See [Add Firebase to your Android project](/docs/android/setup#add-config-file).)\n\nAccess the `firebase::auth::Auth` class The `Auth` class is the gateway for all API calls.\n\n1. Add the Auth and App header files: \n\n ```c++\n #include \"firebase/app.h\"\n #include \"firebase/auth.h\"\n ```\n2. In your initialization code, create a [`firebase::App`](/docs/reference/cpp/class/firebase/app) class. \n\n ```c++\n #if defined(__ANDROID__)\n firebase::App* app =\n firebase::App::Create(firebase::AppOptions(), my_jni_env, my_activity);\n #else\n firebase::App* app = firebase::App::Create(firebase::AppOptions());\n #endif // defined(__ANDROID__)\n ```\n3. Acquire the `firebase::auth::Auth` class for your `firebase::App`. There is a one-to-one mapping between `App` and `Auth`. \n\n ```c++\n firebase::auth::Auth* auth = firebase::auth::Auth::GetAuth(app);\n ```\n\nAuthenticate with Firebase\n\n1. Follow instructions for [Android](/docs/auth/android/google-signin#authenticate_with_firebase) and [iOS+](/docs/auth/ios/google-signin#2_implement_google_sign-in) to get an ID token for the Google sign in.\n2. After a user successfully signs in, exchange the ID token for a Firebase credential, and authenticate with Firebase using the Firebase credential: \n\n ```c++\n firebase::auth::Credential credential =\n firebase::auth::GoogleAuthProvider::GetCredential(google_id_token,\n nullptr);\n firebase::Future\u003cfirebase::auth::AuthResult\u003e result =\n auth-\u003eSignInAndRetrieveDataWithCredential(credential);\n ```\n3. If your program has an update loop that runs regularly (say at 30 or 60 times per second), you can check the results once per update with `Auth::SignInAndRetrieveDataWithCredentialLastResult`: \n\n ```c++\n firebase::Future\u003cfirebase::auth::AuthResult\u003e result =\n auth-\u003eSignInAndRetrieveDataWithCredentialLastResult();\n if (result.status() == firebase::kFutureStatusComplete) {\n if (result.error() == firebase::auth::kAuthErrorNone) {\n firebase::auth::AuthResult auth_result = *result.result();\n printf(\"Sign in succeeded for `%s`\\n\",\n auth_result.user.display_name().c_str());\n } else {\n printf(\"Sign in failed with error '%s'\\n\", result.error_message());\n }\n }\n ```\n Or, if your program is event driven, you may prefer to [register a callback on the\n Future](#register_callback_on_future).\n\nRegister a callback on a Future Some programs have `Update` functions that are called 30 or 60 times per second. For example, many games follow this model. These programs can call the `LastResult` functions to poll asynchronous calls. However, if your program is event driven, you may prefer to register callback functions. A callback function is called upon completion of the Future. \n\n```c++\nvoid OnCreateCallback(const firebase::Future\u003cfirebase::auth::User*\u003e& result,\n void* user_data) {\n // The callback is called when the Future enters the `complete` state.\n assert(result.status() == firebase::kFutureStatusComplete);\n\n // Use `user_data` to pass-in program context, if you like.\n MyProgramContext* program_context = static_cast\u003cMyProgramContext*\u003e(user_data);\n\n // Important to handle both success and failure situations.\n if (result.error() == firebase::auth::kAuthErrorNone) {\n firebase::auth::User* user = *result.result();\n printf(\"Create user succeeded for email %s\\n\", user-\u003eemail().c_str());\n\n // Perform other actions on User, if you like.\n firebase::auth::User::UserProfile profile;\n profile.display_name = program_context-\u003edisplay_name;\n user-\u003eUpdateUserProfile(profile);\n\n } else {\n printf(\"Created user failed with error '%s'\\n\", result.error_message());\n }\n}\n\nvoid CreateUser(firebase::auth::Auth* auth) {\n // Callbacks work the same for any firebase::Future.\n firebase::Future\u003cfirebase::auth::AuthResult\u003e result =\n auth-\u003eCreateUserWithEmailAndPasswordLastResult();\n\n // `&my_program_context` is passed verbatim to OnCreateCallback().\n result.OnCompletion(OnCreateCallback, &my_program_context);\n}\n```\nThe callback function can also be a lambda, if you prefer. \n\n```c++\nvoid CreateUserUsingLambda(firebase::auth::Auth* auth) {\n // Callbacks work the same for any firebase::Future.\n firebase::Future\u003cfirebase::auth::AuthResult\u003e result =\n auth-\u003eCreateUserWithEmailAndPasswordLastResult();\n\n // The lambda has the same signature as the callback function.\n result.OnCompletion(\n [](const firebase::Future\u003cfirebase::auth::User*\u003e& result,\n void* user_data) {\n // `user_data` is the same as &my_program_context, below.\n // Note that we can't capture this value in the [] because std::function\n // is not supported by our minimum compiler spec (which is pre C++11).\n MyProgramContext* program_context =\n static_cast\u003cMyProgramContext*\u003e(user_data);\n\n // Process create user result...\n (void)program_context;\n },\n &my_program_context);\n}\n```\n\nNext steps\n\nAfter a user signs in for the first time, a new user account is created and\nlinked to the credentials---that is, the user name and password, phone\nnumber, or auth provider information---the user signed in with. This new\naccount is stored as part of your Firebase project, and can be used to identify\na user across every app in your project, regardless of how the user signs in.\n\n- In your apps, you can get the user's basic profile information from the\n [`firebase::auth::User`](/docs/reference/cpp/class/firebase/auth/user) object:\n\n ```c++\n firebase::auth::User user = auth-\u003ecurrent_user();\n if (user.is_valid()) {\n std::string name = user.display_name();\n std::string email = user.email();\n std::string photo_url = user.photo_url();\n // The user's ID, unique to the Firebase project.\n // Do NOT use this value to authenticate with your backend server,\n // if you have one. Use firebase::auth::User::Token() instead.\n std::string uid = user.uid();\n }\n ```\n- In your Firebase Realtime Database and Cloud Storage\n [Security Rules](/docs/database/security/user-security), you can\n get the signed-in user's unique user ID from the `auth` variable,\n and use it to control what data a user can access.\n\nYou can allow users to sign in to your app using multiple authentication\nproviders by [linking auth provider credentials to an\nexisting user account.](/docs/auth/cpp/account-linking)\n\nTo sign out a user, call [`SignOut()`](/docs/reference/cpp/class/firebase/auth/auth#signout): \n\n```c++\nauth-\u003eSignOut();\n```"]]
