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.
- In your project-level
build.gradle
file, make sure to include Google's Maven repository in both yourbuildscript
andallprojects
sections. Add the dependency for the Firebase Authentication Android library to your module (app-level) Gradle file (usually
app/build.gradle
):implementation 'com.google.firebase:firebase-auth:19.2.0'
- 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.
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:Java
// Initialize Facebook Login button mCallbackManager = CallbackManager.Factory.create(); LoginButton loginButton = findViewById(R.id.buttonFacebookLogin); 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); }
Kotlin
// 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) }
- In your sign-in activity's
onCreate
method, get the shared instance of theFirebaseAuth
object:Java
private FirebaseAuth mAuth; // ... // Initialize Firebase Auth mAuth = FirebaseAuth.getInstance();
Kotlin
private lateinit var auth: FirebaseAuth // ... // Initialize Firebase Auth auth = FirebaseAuth.getInstance()
- When initializing your Activity, check to see if the user is currently signed in:
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); }
Kotlin
public override fun onStart() { super.onStart() // Check if user is signed in (non-null) and update UI accordingly. val currentUser = auth.currentUser 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: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); } // ... } }); }
Kotlin
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) } // ... } }
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
:
Java
FirebaseAuth.getInstance().signOut();
Kotlin
FirebaseAuth.getInstance().signOut()