e.java

// CONTACT.JAVA

import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;

public class Contact {
    private StringProperty name = new SimpleStringProperty();
    private StringProperty contactNumber = new SimpleStringProperty();

    public Contact(String name, String contactNumber) {
        this.name.set(name);
        this.contactNumber.set(contactNumber);
    }

    @Override
    public String toString() { return String.format("(%s, %s)", name.getValue(), contactNumber.getValue()); }

    public String getName() { return name.get(); }

    public StringProperty nameProperty() { return name; }

    public String getContactNumber() { return contactNumber.get(); }

    public StringProperty contactNumberProperty() { return contactNumber; }
}

// CONTROLLER.JAVA

import javafx.beans.property.IntegerProperty;
import javafx.beans.property.Property;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;

import java.util.ArrayList;

public class Controller {
    private ArrayList<Contact> contacts = new ArrayList<Contact>();
    private IntegerProperty currentIndex = new SimpleIntegerProperty(-1);
    private IntegerProperty currentSize = new SimpleIntegerProperty(0);
    private Property<Contact> currentContact = new SimpleObjectProperty<Contact>();

    public int getCurrentIndex() { return currentIndex.get(); }

    public IntegerProperty currentIndexProperty() { return currentIndex; }

    public Contact getCurrentContact() { return currentContact.getValue(); }

    public Property<Contact> currentContactProperty() { return currentContact; }


    public void first() {
        if (contacts.size() > 0) currentIndex.set(0);
    }

    public void last() {
        if (contacts.size() > 0) currentIndex.set(contacts.size() - 1);
    }

    public void next() {
        if (currentIndex.get() < (contacts.size() - 1)) currentIndex.set(currentIndex.get() + 1);
    }

    public void previous() {
        if (currentIndex.get() > 0) currentIndex.set(currentIndex.get() - 1);
    }

    public void newContact() {
        Contact contact = new Contact("?", "?");
        contacts.add(contact);
        currentSize.set(contacts.size());
        last();
    }

    private void setupContacts() {
        contacts.add(new Contact("Billy Bob", "081-556-1234"));
        contacts.add(new Contact("Jane Doe", "082-689-2546"));
        contacts.add(new Contact("John Doe", "084-253-1254"));
    }

    private void setupProperties() {
        currentIndex.addListener((observable, oldValue, newValue) -> {
            if ((newValue.intValue() >= 0) && (newValue.intValue() < contacts.size())) {
                System.out.printf("Current index changed, old = %s, new = %s\n", oldValue.intValue(), newValue.intValue());
                currentContact.setValue(contacts.get(newValue.intValue()));
            }
        });

        currentContact.addListener((observable, oldValue, newValue) -> {
            System.out.printf("Contact changed, old = %s, new = %s\n", oldValue, newValue);
            rebindFields(oldValue, newValue);
        });
    }

    public Controller() {
        setupContacts();
        setupProperties();
    }

    private TextField txtName;
    private TextField txtContactNumber;
    private Label lblInfo;
    private Button btnPrev;
    private Button btnNew;
    private Button btnNext;

    private void rebindFields(Contact oldContact, Contact newContact) {
        if (oldContact != null) {
            txtName.textProperty().unbindBidirectional(oldContact.nameProperty());
            txtContactNumber.textProperty().unbindBidirectional(oldContact.contactNumberProperty());
        }
        if (newContact != null) {
            txtName.textProperty().bindBidirectional(newContact.nameProperty());
            txtContactNumber.textProperty().bindBidirectional(newContact.contactNumberProperty());
        }
    }

    public void connectToUI(Scene scene) {
        txtName = (TextField) scene.lookup("#name");
        txtContactNumber = (TextField) scene.lookup("#number");
        lblInfo = (Label) scene.lookup("#info");
        btnPrev = (Button) scene.lookup("#prev");
        btnNew = (Button) scene.lookup("#new");
        btnNext = (Button) scene.lookup("#next");
        
        lblInfo.textProperty().bind(currentIndex.add(1).asString().concat(" of ").concat(currentSize));
        // Fluent binding
        currentSize.set(contacts.size());

        btnPrev.setOnAction(event -> previous());
        btnNew.setOnAction(event -> newContact());
        btnNext.setOnAction(event -> next());
    }
}

// MAIN


import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class Example extends Application {
    public static void main(String[] args) {
      launch(args);
    }

    protected Scene createScene() {
        VBox root = new VBox();
        root.setSpacing(10);
        root.setOpaqueInsets(new Insets(10, 10, 10, 10));
        root.setFillWidth(true);

        Label lblName = new Label("Name");
        TextField txtName = new TextField();
        txtName.setId("name");

        Label lblNumber = new Label("Contact Number");
        TextField txtNumber = new TextField();
        txtNumber.setId("number");

        Label lblInfo = new Label("X of Y");
        lblInfo.setId("info");

        Button btnPrev = new Button("<");
        btnPrev.setId("prev");

        Button btnNew = new Button("+");
        btnNew.setId("new");

        Button btnNext = new Button(">");
        btnNext.setId("next");

        HBox buttons = new HBox();
        buttons.getChildren().addAll(btnPrev, btnNew, btnNext);
        buttons.setSpacing(5);
        buttons.setFillHeight(true);

        root.getChildren().addAll(lblName, txtName, lblNumber, txtNumber, lblInfo, buttons);
        return new Scene(root);
    }

    @Override
    public void start(Stage primaryStage) throws Exception {
        Scene scene = createScene();
        Controller controller = new Controller();
        controller.connectToUI(scene);
        controller.first();
        primaryStage.setTitle("Example 4");
        primaryStage.setWidth(300);
        primaryStage.setScene(scene);
        primaryStage.show();
    }
}