Using Firebase for user registration and login

In this page we will demonstrate how firebase could be used for user registration and login activity.

First, design the page to facilitate both registration and login activity.

<?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="20dp">


    <EditText
        android:id="@+id/etEmail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Email" />

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

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

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

</LinearLayout>

Add the dependencies in build.gradle file

implementation 'com.google.firebase:firebase-auth:22.1.1'
implementation 'com.google.firebase:firebase-firestore:24.9.1'

Main activity page code

package com.example.firebase_user_register_login_demo_2024;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;

public class MainActivity extends AppCompatActivity {

    private EditText etEmail, etPassword;
    private Button btnRegister, btn_login;
    private FirebaseAuth mAuth;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mAuth=FirebaseAuth.getInstance();

        etEmail=findViewById(R.id.etEmail);
        etPassword=findViewById(R.id.etPassword);

        // FOLLOWING CODE IS FOR REGISTRATION OF THE USER
        btnRegister= findViewById(R.id.btn_register);
        btnRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String email, password;
                email=String.valueOf(etEmail.getText().toString());
                password=String.valueOf(etPassword.getText().toString());
                if(TextUtils.isEmpty(email)){
                    Toast.makeText(MainActivity.this, "Enter Email", Toast.LENGTH_SHORT).show();
                }
                if(TextUtils.isEmpty(password)){
                    Toast.makeText(MainActivity.this, "Enter Password", Toast.LENGTH_SHORT).show();
                }

                mAuth.createUserWithEmailAndPassword(email,password)
                        .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                            @Override
                            public void onComplete(@NonNull Task<AuthResult> task) {
                                if(task.isSuccessful()){
                                    Toast.makeText(MainActivity.this, "Account Created", Toast.LENGTH_SHORT).show();
                                    Intent in= new Intent(MainActivity.this, Registration.class);
                                    startActivity(in);
                                    finish();
                                }
                                else {
                                    String errorMessage = task.getException().getMessage();
                                    Toast.makeText(MainActivity.this, "Error: " + errorMessage, Toast.LENGTH_LONG).show();
                                    //Toast.makeText(MainActivity.this, "Account creation failed", Toast.LENGTH_SHORT).show();
                                }
                            }
                        });
            }
        });

        // FOLLOWING CODE IS FOR USER LOGIN

        btn_login=findViewById(R.id.btn_login);
        btn_login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String email, password;
                email=String.valueOf(etEmail.getText().toString());
                password=String.valueOf(etPassword.getText().toString());
                if(TextUtils.isEmpty(email)){
                    Toast.makeText(MainActivity.this, "Enter Email", Toast.LENGTH_SHORT).show();
                }
                if(TextUtils.isEmpty(password)){
                    Toast.makeText(MainActivity.this, "Enter Password", Toast.LENGTH_SHORT).show();
                }

                mAuth.signInWithEmailAndPassword(email, password)
                        .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                            @Override
                            public void onComplete(@NonNull Task<AuthResult> task) {
                                if(task.isSuccessful()){
                                    Toast.makeText(MainActivity.this, "Login Successful", Toast.LENGTH_SHORT).show();
                                    Intent in= new Intent(MainActivity.this, Login_Page.class);
                                    startActivity(in);
                                    finish();
                                } else {
                                    Toast.makeText(MainActivity.this, "Authentication Failed", Toast.LENGTH_SHORT).show();
                                }
                            }
                        });

            }
        });


    }
}

Create a new page and design it

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Login_Page">

    <TextView
        android:id="@+id/txt_login"
        android:layout_width="297dp"
        android:layout_height="104dp"
        android:layout_marginStart="50dp"
        android:layout_marginTop="61dp"
        android:text="Login Successful"
        android:textSize="34sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn_logout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="141dp"
        android:layout_marginTop="129dp"
        android:text="Logout"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/txt_login" />
</androidx.constraintlayout.widget.ConstraintLayout>

package com.example.firebase_user_register_login_demo_2024;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.google.firebase.Firebase;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;

public class Login_Page extends AppCompatActivity {

    private Button btn_logout;
    private FirebaseAuth mAuth;
    private TextView txt_msg;
    FirebaseUser user;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login_page);

        mAuth = FirebaseAuth.getInstance();
        user=mAuth.getCurrentUser();

        txt_msg=findViewById(R.id.txt_login);
        txt_msg.setText("Welcome " + user.getEmail());
        btn_logout=findViewById(R.id.btn_logout);
        btn_logout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                FirebaseAuth.getInstance().signOut();
                Intent in=new Intent(Login_Page.this , MainActivity.class);
                startActivity(in);
                finish();
            }
        });
    }
}

Create Registration page and code as shown below

package com.example.firebase_user_register_login_demo_2024;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;

public class Registration extends AppCompatActivity {

    private Button btn_home;

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

        btn_home=findViewById(R.id.btn_home);
        
        btn_home.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent in=new Intent(Registration.this, MainActivity.class);
                startActivity(in);
                finish();
            }
        });
    }
}