Firebase – Login and Register with Email, Facebook and Google Android

Introduction

Firebase is a powerful backend platform developed by Google that provides a wide range of services for building scalable and secure mobile applications. One of the essential features of Firebase is authentication, which allows users to register and log in to your application using various providers such as email, Facebook, and Google. In this tutorial, we will cover how to implement Firebase authentication in an Android application using email, Facebook, and Google providers.

Prerequisites

Before starting this tutorial, make sure you have the following:

1. Android Studio installed on your computer.
2. A Firebase project created and configured.
3. The Firebase Android SDK installed in your project.
4. Basic knowledge of Android development and Java or Kotlin programming language.

Step 1: Add Firebase Authentication to Your Project

To add Firebase authentication to your project, follow these steps:

1. Open your Android project in Android Studio.
2. In the top-level build.gradle file, add the Firebase Authentication library as a dependency:

   dependencies {
   implementation 'com.google.firebase:firebase-auth:21.0.1'
   }

3. In the app-level build.gradle file, add the Firebase configuration:

   dependencies {
   implementation 'com.google.firebase:firebase-auth:21.0.1'
   implementation 'com.google.firebase:firebase-firestore:23.0.3'
   }

4. Sync your project with the Gradle files.

Step 2: Configure Firebase Authentication

To configure Firebase authentication, follow these steps:

1. Open the Firebase console and navigate to the Authentication section.
2. Click on the "Get started" button to enable authentication.
3. Choose the providers you want to use (email, Facebook, and Google in this case).
4. Click on the "Enable" button to enable the selected providers.

Step 3: Implement Email Registration and Login

To implement email registration and login, follow these steps:

1. Create a new activity for the login screen (e.g., LoginActivity.java):

   public class LoginActivity extends AppCompatActivity {
   private FirebaseAuth mAuth;
   private EditText emailEditText;
   private EditText passwordEditText;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_login);
   
       mAuth = FirebaseAuth.getInstance();
       emailEditText = findViewById(R.id.email_edit_text);
       passwordEditText = findViewById(R.id.password_edit_text);
   
       Button loginButton = findViewById(R.id.login_button);
       loginButton.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               login();
           }
       });
   }
   
   private void login() {
       String email = emailEditText.getText().toString();
       String password = passwordEditText.getText().toString();
   
       mAuth.signInWithEmailAndPassword(email, password)
              .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
                           FirebaseUser user = mAuth.getCurrentUser();
                           Toast.makeText(LoginActivity.this, "Login successful", Toast.LENGTH_SHORT).show();
                           Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                           startActivity(intent);
                       } else {
                           // If sign in fails, display a message to the user.
                           Toast.makeText(LoginActivity.this, "Authentication failed.", Toast.LENGTH_SHORT).show();
                       }
                   }
               });
   }
   }

2. Create a new activity for the registration screen (e.g., RegisterActivity.java):

   public class RegisterActivity extends AppCompatActivity {
   private FirebaseAuth mAuth;
   private EditText emailEditText;
   private EditText passwordEditText;
   private EditText confirmPasswordEditText;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_register);
   
       mAuth = FirebaseAuth.getInstance();
       emailEditText = findViewById(R.id.email_edit_text);
       passwordEditText = findViewById(R.id.password_edit_text);
       confirmPasswordEditText = findViewById(R.id.confirm_password_edit_text);
   
       Button registerButton = findViewById(R.id.register_button);
       registerButton.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               register();
           }
       });
   }
   
   private void register() {
       String email = emailEditText.getText().toString();
       String password = passwordEditText.getText().toString();
       String confirmPassword = confirmPasswordEditText.getText().toString();
   
       if (!password.equals(confirmPassword)) {
           Toast.makeText(RegisterActivity.this, "Passwords do not match", Toast.LENGTH_SHORT).show();
           return;
       }
   
       mAuth.createUserWithEmailAndPassword(email, password)
              .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
                           FirebaseUser user = mAuth.getCurrentUser();
                           Toast.makeText(RegisterActivity.this, "Registration successful", Toast.LENGTH_SHORT).show();
                           Intent intent = new Intent(RegisterActivity.this, LoginActivity.class);
                           startActivity(intent);
                       } else {
                           // If sign up fails, display a message to the user.
                           Toast.makeText(RegisterActivity.this, "Authentication failed.", Toast.LENGTH_SHORT).show();
                       }
                   }
               });
   }
   }

   Step 4: Implement Facebook and Google Registration and Login

To implement Facebook and Google registration and login, follow these steps:

1. Add the Facebook SDK to your project:

   dependencies {
   implementation 'com.facebook.android:facebook-android-sdk:5.14.0'
   }

2. Add the Google Play Services SDK to your project:

   dependencies {
   implementation 'com.google.android.gms:play-services-auth:19.2.0'
   }

3. Implement Facebook login:

   private void facebookLogin() {
   FacebookSdk.sdkInitialize(this);
   AppEventsLogger.activateApp(this);
   
   LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("email", "public_profile"));
   
   LoginManager.getInstance().registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
       @Override
       public void onSuccess(LoginResult loginResult) {
           GraphRequest request = GraphRequest.newMeRequest(loginResult.getAccessToken(), new GraphRequest.GraphJSONObjectCallback() {
               @Override
               public void onCompleted(JSONObject object, GraphResponse response) {
                   try {
                       String facebookId = object.getString("id");
                       String name = object.getString("name");
                       String email = object.getString("email");
   
                       mAuth.signInWithFacebook(facebookId, name, email)
                              .addOnCompleteListener(LoginActivity.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
                                           FirebaseUser user = mAuth.getCurrentUser();
                                           Toast.makeText(LoginActivity.this, "Facebook login successful", Toast.LENGTH_SHORT).show();
                                           Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                                           startActivity(intent);
                                       } else {
                                           // If sign in fails, display a message to the user.
                                           Toast.makeText(LoginActivity.this, "Authentication failed.", Toast.LENGTH_SHORT).show();
                                       }
                                   }
                               });
                   } catch (JSONException e) {
                       e.printStackTrace();
                   }
               }
           });
           Bundle parameters = new Bundle();
           parameters.putString("fields", "id,name,email");
           request.setParameters(parameters);
           request.executeAsync();
       }
   
       @Override
       public void onCancel() {
           // App code
       }
   
       @Override
       public void onError(FacebookException e) {
           // App code
       }
   });
   }

4. Implement Google login:

   
   private void googleLogin() {
   GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
          .requestEmail()
          .build();
   
   GoogleSignInClient googleSignInClient = GoogleSignIn.getClient(this, gso);
   
   Intent signInIntent = googleSignInClient.getSignInIntent();
   startActivityForResult(signInIntent, RC_SIGN_IN);
   }

@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data);

if (requestCode == RC_SIGN_IN) {
    Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
    handleSignInResult(task);
} else {
    callbackManager.onActivityResult(requestCode, resultCode, data);
}

}

private void handleSignInResult(Task completedTask) { try { GoogleSignInAccount account = completedTask.getResult(ApiException.class); String idToken = account.getIdToken();

    mAuth.signInWithGoogle(idToken)
           .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
                        FirebaseUser user = mAuth.getCurrentUser();
                        Toast.makeText(LoginActivity.this, "Google login successful", Toast.LENGTH_SHORT).show();
                        Intent intent = new Intent(LoginActivity.this, MainActivity.class);
                        startActivity(intent);
                    } else {
                        // If sign in fails, display a message to the user.
                        Toast.makeText(LoginActivity.this, "Authentication failed.", Toast.LENGTH_SHORT).show();
                    }
                }
            });
} catch (ApiException e) {
    // The ApiException status code indicates the detailed failure reason.
    // Please refer to the GoogleSignInStatusCodes class for more information.
    Log.w("TAG", "Google sign in failed", e);
}

}

**Conclusion**

In this tutorial, we have learned how to implement Firebase authentication in an Android application using email, Facebook, and Google providers. We have covered the steps to add Firebase authentication to your project, configure Firebase authentication, implement email registration and login, and implement Facebook and Google registration and login. With this tutorial, you should be able to integrate Firebase authentication into your Android application and provide a seamless login experience for your users.