Authenticate Using Twitter on Android

You can let your users authenticate with Firebase using their Twitter accounts by integrating Sign in with Twitter into your app.

Before you begin

1. Add Firebase to your Android project.
2. If you haven't yet connected your app to your Firebase project, do so from the Firebase console.
3. Add the dependency for Firebase Authentication to your app-level build.gradle file:

   compile 'com.google.firebase:firebase-auth:9.6.1'

4. Register your app as a developer application on Twitter and get your app's API Key and API Secret.
5. Enable Twitter Login:
   1. In the Firebase console, open the Auth section.
   2. On the Sign in method tab, enable the Twitter sign-in method and specify the API Key and API Secret you got from Twitter.
   3. Then, make sure your Firebase OAuth redirect URI (e.g. my-app-12345.firebaseapp.com/__/auth/handler) is set as your Callback URL in your app's settings page on your Twitter app's config.

Authenticate with Firebase

1. Integrate Sign in with Twitter into your app by following the developer's documentation. At the end of the Twitter sign-in flow, you will receive an OAuth access token and an OAuth secret.
2. In your sign-in activity's onCreate method, get the shared instance of the FirebaseAuth object:

   private FirebaseAuth mAuth;
   // ...
   // Initialize Firebase Auth
   mAuth = FirebaseAuth.getInstance();
   TwitterLoginActivity.java
   

3. Set up an AuthStateListener that responds to changes in the user's sign-in state:

   private FirebaseAuth.AuthStateListener mAuthListener;
   
   // ...
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       // ...
       mAuthListener = new FirebaseAuth.AuthStateListener() {
           @Override
           public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
               FirebaseUser user = firebaseAuth.getCurrentUser();
               if (user != null) {
                   // User is signed in
                   Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
               } else {
                   // User is signed out
                   Log.d(TAG, "onAuthStateChanged:signed_out");
               }
               // ...
           }
       };
       // ...
   }
   
   @Override
   public void onStart() {
       super.onStart();
       mAuth.addAuthStateListener(mAuthListener);
   }
   
   @Override
   public void onStop() {
       super.onStop();
       if (mAuthListener != null) {
           mAuth.removeAuthStateListener(mAuthListener);
       }
   }
   TwitterLoginActivity.java
   

4. After a user successfully signs in with Twitter, exchange the OAuth access token and OAuth secret for a Firebase credential, and authenticate with Firebase using the Firebase credential:

   private void handleTwitterSession(TwitterSession session) {
       Log.d(TAG, "handleTwitterSession:" + session);
   
       AuthCredential credential = TwitterAuthProvider.getCredential(
               session.getAuthToken().token,
               session.getAuthToken().secret);
   
       mAuth.signInWithCredential(credential)
               .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                   @Override
                   public void onComplete(@NonNull Task<AuthResult> task) {
                       Log.d(TAG, "signInWithCredential:onComplete:" + task.isSuccessful());
   
                       // If sign in fails, display a message to the user. If sign in succeeds
                       // the auth state listener will be notified and logic to handle the
                       // signed in user can be handled in the listener.
                       if (!task.isSuccessful()) {
                           Log.w(TAG, "signInWithCredential", task.getException());
                           Toast.makeText(TwitterLoginActivity.this, "Authentication failed.",
                                   Toast.LENGTH_SHORT).show();
                       }
   
                       // ...
                   }
               });
   }
   TwitterLoginActivity.java
   

   If the call to signInWithCredential succeeds, the AuthStateListener runs the onAuthStateChanged callback. In the callback, you can use the getCurrentUser 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, 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 Firebase 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:

FirebaseAuth.getInstance().signOut();