How to Create a User Registration Activity in Android using Firebase Authentication

In this tutorial, we will create a simple user registration screen using Firebase Authentication in an Android app. We will use Java for the logic and XML for the layout.

Step 1: Set Up Firebase in Your Android Project

1. Add Firebase to your Android project: Go to the Firebase Console and add your Android app. Download the google-services.json file and place it in the app directory of your project.
2. Add Firebase SDK to your project: Open your build.gradle files and add the necessary dependencies.

// Project-level build.gradle
buildscript {
    // ...
    dependencies {
        // ...
        classpath 'com.google.gms:google-services:4.3.8' // Check for the latest version
    }
}

// App-level build.gradle
apply plugin: 'com.android.application'
apply plugin: 'com.google.gms.google-services'

android {
    // ...
}

dependencies {
    // ...
    implementation 'com.google.firebase:firebase-auth:21.0.1' // Check for the latest version
}

Step 2: Create the Layout XML

Create a new XML layout file activity_register.xml in the res/layout directory. This file will define the UI components for the registration screen.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp">

    <EditText
        android:id="@+id/etEmail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Email"
        android:inputType="textEmailAddress"
        android:marginBottom="16dp"/>

    <EditText
        android:id="@+id/etPassword"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Password"
        android:inputType="textPassword"
        android:marginBottom="16dp"/>

    <Button
        android:id="@+id/btnRegister"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Register"/>

</LinearLayout>

Step 3: Create the Java Activity

Create a new Java class RegisterActivity.java in the com.apdim3.firebaseeverythink package.

package com.apdim3.firebaseeverythink;

import android.os.Bundle;
import android.text.TextUtils;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.google.firebase.auth.FirebaseAuth;

public class RegisterActivity extends AppCompatActivity {

    private EditText edEmail, edPassword;
    private Button btnRegister;
    private FirebaseAuth auth;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);

        edEmail = findViewById(R.id.etEmail);
        edPassword = findViewById(R.id.etPassword);
        btnRegister = findViewById(R.id.btnRegister);
        auth = FirebaseAuth.getInstance();

        btnRegister.setOnClickListener(v -> {
            String email = edEmail.getText().toString();
            String password = edPassword.getText().toString();

            if (TextUtils.isEmpty(email) || TextUtils.isEmpty(password)) {
                Toast.makeText(this, "Please fill the Information", Toast.LENGTH_SHORT).show();
            } else if (password.length() < 6) {
                Toast.makeText(this, "Password too weak", Toast.LENGTH_SHORT).show();
            } else {
                registerUser(email, password);
            }
        });
    }

    private void registerUser(String email, String password) {
        auth.createUserWithEmailAndPassword(email, password)
            .addOnCompleteListener(this, task -> {
                if (task.isSuccessful()) {
                    Toast.makeText(RegisterActivity.this, "Registration successful!", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(RegisterActivity.this, "Registration failed: " + task.getException().getMessage(), Toast.LENGTH_SHORT).show();
                }
            });
    }
}

Step 4: Add Activity to the Manifest

Make sure to declare your RegisterActivity in the AndroidManifest.xml.

<activity android:name=".RegisterActivity"></activity>

Step 5: Run Your Application

Ensure you have a connected device or emulator. Run your application, and you should see the registration screen. Enter an email and password to register a new user.

By following these steps, you've created a user registration screen in your Android app using Firebase Authentication. You can now expand on this foundation by adding additional features such as email verification, password reset, or a login screen.