Authenticate Using Twitter on Android

You can let your users authenticate with Firebase using their Twitter accounts by integrating Twitter authentication 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:10.2.6'

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. 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
   

2. When initializing your Activity, check to see if the user is currently signed in:

   @Override
   public void onStart() {
       super.onStart();
       // Check if user is signed in (non-null) and update UI accordingly.
       FirebaseUser currentUser = mAuth.getCurrentUser();
       updateUI(currentUser);
   }
   TwitterLoginActivity.java
   

3. 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. You should have code in your Activity that looks something like this;

   private TwitterLoginButton mLoginButton;
   
   // ...
   
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       // ...
       mLoginButton = (TwitterLoginButton) findViewById(R.id.button_twitter_login);
       mLoginButton.setCallback(new Callback<TwitterSession>() {
           @Override
           public void success(Result<TwitterSession> result) {
               Log.d(TAG, "twitterLogin:success" + result);
               handleTwitterSession(result.data);
           }
   
           @Override
           public void failure(TwitterException exception) {
               Log.w(TAG, "twitterLogin:failure", exception);
               updateUI(null);
           }
       });
   }
   
   // ...
   
   @Override
   protected void onActivityResult(int requestCode, int resultCode, Intent data) {
       super.onActivityResult(requestCode, resultCode, data);
   
       // Pass the activity result to the Twitter login button.
       mLoginButton.onActivityResult(requestCode, resultCode, data);
   }
   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) {
                       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(TwitterLoginActivity.this, "Authentication failed.",
                                   Toast.LENGTH_SHORT).show();
                           updateUI(null);
                       }
   
                       // ...
                   }
               });
   }
   TwitterLoginActivity.java
   

   If the call to signInWithCredential succeeds, you can use the returned FirebaseUser to proceed.

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:

FirebaseAuth.getInstance().signOut();