Authenticate with Firebase using Password-Based Accounts on Android

You can use Firebase Authentication to let your users authenticate with Firebase using their email addresses and passwords, and to manage your app's password-based accounts.

Before you begin

  1. Add Firebase to your Android project.
  2. Add the dependency for Firebase Authentication to your app-level build.gradle file:
    compile 'com.google.firebase:firebase-auth:10.2.0'
  3. If you haven't yet connected your app to your Firebase project, do so from the Firebase console.
  4. Enable Email/Password sign-in:
    1. In the Firebase console, open the Auth section.
    2. On the Sign in method tab, enable the Email/password sign-in method and click Save.

Create a password-based account

To create a new user account with a password, complete the following steps in your app's sign-in activity:

  1. In your sign-up activity's onCreate method, get the shared instance of the FirebaseAuth object:
    private FirebaseAuth mAuth;
    // ...
    mAuth = FirebaseAuth.getInstance();
    
  2. 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);
        }
    }
    
  3. When a new user signs up using your app's sign-up form, complete any new account validation steps that your app requires, such as verifying that the new account's password was correctly typed and meets your complexity requirements.
  4. Create a new account by passing the new user's email address and password to createUserWithEmailAndPassword:
    mAuth.createUserWithEmailAndPassword(email, password)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    Log.d(TAG, "createUserWithEmail: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()) {
                        Toast.makeText(EmailPasswordActivity.this, R.string.auth_failed,
                                Toast.LENGTH_SHORT).show();
                    }
    
                    // ...
                }
            });
    
    If the new account was created, the user is also signed in, and the AuthStateListener runs the onAuthStateChanged callback. In the callback, you can use the getCurrentUser method to get the user's account data.

Sign in a user with an email address and password

The steps for signing in a user with a password are similar to the steps for creating a new account. In your app's sign-in activity, do the following:

  1. In your sign-in activity's onCreate method, get the shared instance of the FirebaseAuth object:
    private FirebaseAuth mAuth;
    // ...
    mAuth = FirebaseAuth.getInstance();
    
  2. 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);
        }
    }
    
  3. When a user signs in to your app, pass the user's email address and password to signInWithEmailAndPassword:
    mAuth.signInWithEmailAndPassword(email, password)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    Log.d(TAG, "signInWithEmail: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, "signInWithEmail:failed", task.getException());
                        Toast.makeText(EmailPasswordActivity.this, R.string.auth_failed,
                                Toast.LENGTH_SHORT).show();
                    }
    
                    // ...
                }
            });
    
    If sign-in succeeded, 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 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();

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