Email and password authentication using Firebase on Whats App clone

Step 1 : Create UI for authentication

<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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/grayBackground"
    android:gravity="center"
    android:orientation="vertical"
    android:padding="15dp"
    tools:context=".signup_activity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="30dp"
        android:gravity="center_horizontal"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/imageView3"
            android:layout_width="100dp"
            android:layout_height="100dp"
            app:srcCompat="@drawable/ic_whatsapp" />

        <EditText
            android:id="@+id/txtUsername"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="15dp"
            android:layout_marginBottom="10dp"
            android:layout_weight="1"
            android:background="@color/white"
            android:ems="10"
            android:hint="Name"
            android:inputType="textPersonName"
            android:padding="9dp" />

        <EditText
            android:id="@+id/txtEmail"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_weight="1"
            android:background="@color/white"
            android:ems="10"
            android:hint="Email"
            android:inputType="textEmailAddress"
            android:padding="9dp" />

        <EditText
            android:id="@+id/txtPassword"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_weight="1"
            android:background="@color/white"
            android:ems="10"
            android:hint="Password"
            android:inputType="textPassword"
            android:padding="9dp" />

        <Button
            android:id="@+id/btnSignUp"
            android:layout_width="150dp"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:padding="15dp"
            android:text="Sign up"
            app:cornerRadius="4dp" />

        <TextView
            android:id="@+id/lblAlreadyHaveAccount"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="right"
            android:gravity="right"
            android:padding="3dp"
            android:text="Already have account" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="30dp"
        android:layout_marginEnd="30dp"
        android:orientation="horizontal">

        <Button
            android:id="@+id/btnGoogle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="4dp"
            android:layout_weight="1"
            android:backgroundTint="@color/white"
            android:drawableLeft="@drawable/ic_search"
            android:padding="15dp"
            android:text="Google"
            android:textColor="@color/black"
            app:cornerRadius="4dp" />

        <Button
            android:id="@+id/btnFacebook"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginStart="4dp"
            android:layout_weight="1"
            android:backgroundTint="@color/fb_color"
            android:drawableLeft="@drawable/ic_facebook__2_"
            android:padding="15dp"
            android:text="Facebook"
            app:cornerRadius="4dp" />

    </LinearLayout>

    <TextView
        android:id="@+id/lblSignUp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:text="Sign up with phone"
        android:textColor="@color/colorPrimary"
        android:textSize="18sp" />

</LinearLayout>

Step 2: Connect firebase to android (firebase authentication and Realtime database)

Step 3 : Add dependencies to gradle

plugins {
    id 'com.android.application'
    id 'com.google.gms.google-services'
}

android {
    buildFeatures {
        viewBinding true
    }
    compileSdkVersion 30
    buildToolsVersion "30.0.3"

    defaultConfig {
        applicationId "exm.shailendra.whatsapp"
        minSdkVersion 21
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {

    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation platform('com.google.firebase:firebase-bom:28.0.1')
    implementation 'com.google.firebase:firebase-auth'
    implementation 'com.google.firebase:firebase-database'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

Step 3: JAVA Code

public class signup_activity extends AppCompatActivity {
    ActivitySignupBinding binding;
    private  FirebaseAuth auth;
    private FirebaseDatabase database;
    ProgressDialog progressDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivitySignupBinding.inflate(getLayoutInflater());
        View view = binding.getRoot();
        setContentView(view);
        getSupportActionBar().hide();

        auth = FirebaseAuth.getInstance();
        database = FirebaseDatabase.getInstance();

        progressDialog = new ProgressDialog(signup_activity.this);
        progressDialog.setTitle("Creating Account");
        progressDialog.setMessage("We are creating your account");

        binding.btnSignUp.setOnClickListener(v -> {
            progressDialog.show();
            auth.createUserWithEmailAndPassword(binding.txtEmail.getText().toString(),
                    binding.txtPassword.getText().toString())
                    .addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NotNull Task<AuthResult> task) {
                    progressDialog.dismiss();

                    if (task.isSuccessful()){
                        Toast.makeText(signup_activity.this, "User created successfully",
                                Toast.LENGTH_SHORT).show();
                        User user = new User(binding.txtUsername.getText().toString(), binding
                                .txtEmail.getText().toString(),binding.txtPassword.getText().toString());

                        String id = task.getResult().getUser().getUid();
                        database.getReference().child("Users").child(id).setValue(user);


                    }
                    else {
                        Toast.makeText(signup_activity.this, task.getException().getMessage(), Toast.LENGTH_SHORT).show();
                    }

                }
            });
        });
    }
}