You can let your users authenticate with Firebase using their Facebook accounts by integrating Facebook Login into your app.
Before you begin
If you haven't already, add Firebase to your Android project.
- On the Facebook for Developers site, get the App ID and an App Secret for your app.
- Enable Facebook Login:
- In the Firebase console, open the Auth section.
- On the Sign in method tab, enable the Facebook sign-in method and specify the App ID and App Secret you got from Facebook.
- Then, make sure your OAuth redirect URI (e.g.
my-app-12345.firebaseapp.com/__/auth/handler
) is listed as one of your OAuth redirect URIs in your Facebook app's settings page on the Facebook for Developers site in the Product Settings > Facebook Login config.
In your module (app-level) Gradle file (usually
<project>/<app-module>/build.gradle.kts
or<project>/<app-module>/build.gradle
), add the dependency for the Firebase Authentication library for Android. We recommend using the Firebase Android BoM to control library versioning.dependencies { // Import the BoM for the Firebase platform implementation(platform("com.google.firebase:firebase-bom:33.4.0")) // Add the dependency for the Firebase Authentication library // When using the BoM, you don't specify versions in Firebase library dependencies implementation("com.google.firebase:firebase-auth") }
By using the Firebase Android BoM, your app will always use compatible versions of Firebase Android libraries.
(Alternative) Add Firebase library dependencies without using the BoM
If you choose not to use the Firebase BoM, you must specify each Firebase library version in its dependency line.
Note that if you use multiple Firebase libraries in your app, we strongly recommend using the BoM to manage library versions, which ensures that all versions are compatible.
dependencies { // Add the dependency for the Firebase Authentication library // When NOT using the BoM, you must specify versions in Firebase library dependencies implementation("com.google.firebase:firebase-auth:23.0.0") }
Authenticate with Firebase
- Integrate Facebook Login into your app by following the
developer's documentation. When you configure the
LoginButton
orLoginManager
object, request thepublic_profile
andemail
permissions. If you integrated Facebook Login using aLoginButton
, your sign-in activity has code similar to the following:Kotlin+KTX
// Initialize Facebook Login button callbackManager = CallbackManager.Factory.create() buttonFacebookLogin.setReadPermissions("email", "public_profile") buttonFacebookLogin.registerCallback( callbackManager, object : FacebookCallback<LoginResult> { override fun onSuccess(loginResult: LoginResult) { Log.d(TAG, "facebook:onSuccess:$loginResult") handleFacebookAccessToken(loginResult.accessToken) } override fun onCancel() { Log.d(TAG, "facebook:onCancel") } override fun onError(error: FacebookException) { Log.d(TAG, "facebook:onError", error) } }, ) // ... override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) { super.onActivityResult(requestCode, resultCode, data) // Pass the activity result back to the Facebook SDK callbackManager.onActivityResult(requestCode, resultCode, data) }
Java
// Initialize Facebook Login button mCallbackManager = CallbackManager.Factory.create(); LoginButton loginButton = findViewById(R.id.button_sign_in); loginButton.setReadPermissions("email", "public_profile"); loginButton.registerCallback(mCallbackManager, new FacebookCallback<LoginResult>() { @Override public void onSuccess(LoginResult loginResult) { Log.d(TAG, "facebook:onSuccess:" + loginResult); handleFacebookAccessToken(loginResult.getAccessToken()); } @Override public void onCancel() { Log.d(TAG, "facebook:onCancel"); } @Override public void onError(FacebookException error) { Log.d(TAG, "facebook:onError", error); } }); // ... @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); // Pass the activity result back to the Facebook SDK mCallbackManager.onActivityResult(requestCode, resultCode, data); }
- In your sign-in activity's
onCreate
method, get the shared instance of theFirebaseAuth
object:Kotlin+KTX
private lateinit var auth: FirebaseAuth // ... // Initialize Firebase Auth auth = Firebase.auth
Java
private FirebaseAuth mAuth; // ... // Initialize Firebase Auth mAuth = FirebaseAuth.getInstance();
- When initializing your Activity, check to see if the user is currently signed in:
Kotlin+KTX
public override fun onStart() { super.onStart() // Check if user is signed in (non-null) and update UI accordingly. val currentUser = auth.currentUser updateUI(currentUser) }
Java
@Override public void onStart() { super.onStart(); // Check if user is signed in (non-null) and update UI accordingly. FirebaseUser currentUser = mAuth.getCurrentUser(); updateUI(currentUser); }
- After a user successfully signs in, in the
LoginButton
'sonSuccess
callback method, get an access token for the signed-in user, exchange it for a Firebase credential, and authenticate with Firebase using the Firebase credential:Kotlin+KTX
private fun handleFacebookAccessToken(token: AccessToken) { Log.d(TAG, "handleFacebookAccessToken:$token") val credential = FacebookAuthProvider.getCredential(token.token) auth.signInWithCredential(credential) .addOnCompleteListener(this) { task -> if (task.isSuccessful) { // Sign in success, update UI with the signed-in user's information Log.d(TAG, "signInWithCredential:success") val user = auth.currentUser updateUI(user) } else { // If sign in fails, display a message to the user. Log.w(TAG, "signInWithCredential:failure", task.exception) Toast.makeText( baseContext, "Authentication failed.", Toast.LENGTH_SHORT, ).show() updateUI(null) } } }
Java
private void handleFacebookAccessToken(AccessToken token) { Log.d(TAG, "handleFacebookAccessToken:" + token); AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken()); mAuth.signInWithCredential(credential) .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { if (task.isSuccessful()) { // Sign in success, update UI with the signed-in user's information Log.d(TAG, "signInWithCredential:success"); FirebaseUser user = mAuth.getCurrentUser(); updateUI(user); } else { // If sign in fails, display a message to the user. Log.w(TAG, "signInWithCredential:failure", task.getException()); Toast.makeText(FacebookLoginActivity.this, "Authentication failed.", Toast.LENGTH_SHORT).show(); updateUI(null); } } }); }
signInWithCredential
succeeds, you can use thegetCurrentUser
method to get the user's account data.
Next steps
After a user signs in for the first time, a new user account is created and linked to the credentials—that is, the user name and password, phone number, or auth provider information—the user signed in with. This new account is stored as part of your Firebase project, and can be used to identify a user across every app in your project, regardless of how the user signs in.
-
In your apps, you can get the user's basic profile information from the
FirebaseUser
object. See Manage Users. In your Firebase Realtime Database and Cloud Storage Security Rules, you can get the signed-in user's unique user ID from the
auth
variable, and use it to control what data a user can access.
You can allow users to sign in to your app using multiple authentication providers by linking auth provider credentials to an existing user account.
To sign out a user, call
signOut
:
Kotlin+KTX
Firebase.auth.signOut()
Java
FirebaseAuth.getInstance().signOut();