Simple Login App using Firebase

Kindly perform required firebase connectivity using Tools -> Firebase -> Authentication

Java Code

package com.example.firebaseexample;

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

import android.app.ProgressDialog;
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 implements  View.OnClickListener{

    // view objects
    private EditText editTextEmail;
    private EditText editTextPassword;
    private Button buttonSignup;
    private Button buttonLogin;
    private ProgressDialog progressDialog;

    //defining firebaseauth object
    private FirebaseAuth firebaseAuth;

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

        firebaseAuth = FirebaseAuth.getInstance();

        editTextEmail = findViewById(R.id.editTextEmail);
        editTextPassword = findViewById(R.id.editTextPassword);

        buttonSignup = findViewById(R.id.buttonSignup);
        buttonLogin = findViewById(R.id.buttonLogin);

        progressDialog = new ProgressDialog(this);

        buttonSignup.setOnClickListener(this);
        buttonLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                loginUser();
            }
        });
    }

    private void registerUser(){
        // getting email and password
        String email = editTextEmail.getText().toString().trim();
        String password = editTextEmail.getText().toString().trim();

        // Checking if email and password is empty
        if(TextUtils.isEmpty(email)){
            Toast.makeText(this, "Please enter email", Toast.LENGTH_SHORT).show();
            return;
        }
        if(TextUtils.isEmpty(password)){
            Toast.makeText(this, "Please enter password", Toast.LENGTH_SHORT).show();
            return;
        }

        progressDialog.setMessage("Registering Please wait!....");
        progressDialog.show();
        
        // Creating a new user
        firebaseAuth.createUserWithEmailAndPassword(email, password).addOnCompleteListener(
                this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if(task.isSuccessful()){
                            Toast.makeText(MainActivity.this, "Successfully registered!", Toast.LENGTH_SHORT).show();
                        }else{
                            Toast.makeText(MainActivity.this, task.getException().toString(), Toast.LENGTH_SHORT).show();
                        }
                        progressDialog.dismiss();
                    }
                }
        );
    }

    private  void loginUser(){
        // getting email and password
        String email = editTextEmail.getText().toString().trim();
        String password = editTextEmail.getText().toString().trim();

        // Checking if email and password is empty
        if(TextUtils.isEmpty(email)){
            Toast.makeText(this, "Please enter email", Toast.LENGTH_SHORT).show();
            return;
        }
        if(TextUtils.isEmpty(password)){
            Toast.makeText(this, "Please enter password", Toast.LENGTH_SHORT).show();
            return;
        }

        progressDialog.setMessage("Logging in Please wait!....");
        progressDialog.show();

        // Creating a new user
        firebaseAuth.signInWithEmailAndPassword(email, password).addOnCompleteListener(
                this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if(task.isSuccessful()){
                            Toast.makeText(MainActivity.this, "Login Sucessful!", Toast.LENGTH_SHORT).show();
                        }else{
                            Toast.makeText(MainActivity.this, task.getException().toString(), Toast.LENGTH_SHORT).show();
                        }
                        progressDialog.dismiss();
                    }
                }
        );
    }


    @Override
    public void onClick(View view) {
        //calling register method on click
        registerUser();
    }




}

XML Code

<?xml version="1.0" encoding="utf-8"?>


<LinearLayout 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"
tools:context=".MainActivity"
android:layout_centerVertical="true"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">

<EditText
    android:id="@+id/editTextEmail"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="15dp"
    android:hint="Enter email"
    android:inputType="textEmailAddress" />

<EditText
    android:id="@+id/editTextPassword"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="15dp"
    android:hint="Enter password"
    android:inputType="textPassword" />

<Button
    android:id="@+id/buttonSignup"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="15dp"
    android:text="Signup" />


    <Button
        android:id="@+id/buttonLogin"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="15dp"
        android:text="Login" />


</LinearLayout>