Basic JavaFX Application

JavaFXSeeder.java

package com.knoldus.javafx;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.scene.text.Text;
import javafx.scene.text.TextAlignment;
import javafx.stage.Stage;
import javafx.stage.StageStyle;

public class JavaFXSeeder extends Application {
    public final static String ID = "seeder";
    public static final String SEEDER_CONTAINER_ID = "seeder-container-id";
    public final static String SEEDER_BACKGROUND_ID = "seeder-background-id";
    public final static String SEEDER_CONTENT_ID = "seeder-content-id";
    public final static String SEEDER_CONTROLS_ID = "seeder-controls-id";
    public final static String SEEDER_LOGO_ID = "seeder-logo-id";
    public final static String SEEDER_STATUS_ID = "seeder-status-id";
    public final static String SEEDER_CLOSE_BUTTON_ID = "seeder-close-button-id";

    public final static String IMAGES = "file:src/main/resources/img";
    public final static String SEEDER_BACKGROUND = IMAGES + "/seeder-background.jpg";
    public final static String SEEDER_LOGO = IMAGES + "/seeder-logo.gif";
    public final static String SEEDER_ICON = IMAGES + "/seeder-icon.jpg";
    public final static String SEEDER_CLOSE_BUTTON = IMAGES + "/seeder-close-button.png";
    public final static String SEEDER_CLOSE_BUTTON_HOVERED = IMAGES + "/seeder-close-button-hovered.png";

    public final static String SEEDER_STAGE_TITLE = "Loader";
    public final static String SEEDER_STATUS = "Loading";

    public final static double SEEDER_CLOSE_BUTTON_SIZE = 24;
    private static final double SEEDER_WIDTH = 768;
    private static final double SEEDER_HEIGHT = 464;
    private static final double SEEDER_LOGO_SIZE = 200;

    private static double xOffset = 0;
    private static double yOffset = 0;

    private final double SEEDER_STATUS_FONT_SIZE = 24;
    private final String SEEDER_STATUS_FONT_FAMILY = "Roboto Medium";
    private final Color SEEDER_STATUS_COLOR = Color.rgb(25, 25, 25, 1);
    private final Font SEEDER_STATUS_FONT = Font.font(SEEDER_STATUS_FONT_FAMILY, FontWeight.BOLD, SEEDER_STATUS_FONT_SIZE);

    private final StackPane m_seederContainer = new StackPane();
    private final VBox m_seederContent = new VBox();
    private final HBox m_seederControls = new HBox();
    private final ImageView m_seederBackground = new ImageView();
    private final ImageView m_seederLogo = new ImageView();
    private final ImageView m_seederCloseButtonImage = new ImageView();
    private final Text m_seederStatus = new Text();
    private final Button m_seederCloseButton = new Button();
    private final Group m_root = new Group();
    private final Stage m_stage = new Stage();
    private Image m_image;

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage stage) {
        initialize();
        showSeederWindow();
    }

    private void initialize() {
        Scene scene = new Scene(m_root, SEEDER_WIDTH, SEEDER_HEIGHT);
        m_stage.setScene(scene);
        m_stage.setTitle(JavaFXSeeder.SEEDER_STAGE_TITLE);
        m_stage.setHeight(SEEDER_HEIGHT);
        m_stage.setWidth(SEEDER_WIDTH);
        m_stage.initStyle(StageStyle.TRANSPARENT);
        m_stage.getIcons().addAll(new Image(SEEDER_ICON));
        m_stage.setOnCloseRequest(windowEvent ->
        {
            windowEvent.consume();
            handleCloseEvent();
        });

        m_root.setId(ID);

        StackPane.setAlignment(m_seederContainer, Pos.CENTER);

        m_seederContainer.setId(SEEDER_CONTAINER_ID);
        m_seederContainer.setMaxSize(SEEDER_WIDTH, SEEDER_HEIGHT);

        initializeSeederBackground();

        initializeSeederContent();

        initializeSeederControls();

        m_seederContainer.getChildren().addAll(m_seederBackground, m_seederContent, m_seederControls);
        m_root.getChildren().add(m_seederContainer);

        dragSeeder();
    }

    public void initializeSeederBackground() {
        m_image = new Image(SEEDER_BACKGROUND);

        m_seederBackground.setId(SEEDER_BACKGROUND_ID);
        m_seederBackground.setImage(m_image);
        m_seederBackground.setFitWidth(SEEDER_WIDTH);
        m_seederBackground.setFitHeight(SEEDER_HEIGHT);
    }

    public void initializeSeederContent() {
        initializeSeederLogo();
        initializeSeederStatus();

        m_seederContent.getChildren().addAll(m_seederLogo, m_seederStatus);

        m_seederContent.setId(SEEDER_CONTENT_ID);
        m_seederContent.setSpacing(10);
        m_seederContent.setAlignment(Pos.CENTER);
    }

    public void initializeSeederLogo() {
        m_image = new Image(SEEDER_LOGO);

        m_seederLogo.setId(SEEDER_LOGO_ID);
        m_seederLogo.setImage(m_image);
        m_seederLogo.setFitWidth(SEEDER_LOGO_SIZE);
        m_seederLogo.setFitHeight(SEEDER_LOGO_SIZE);
    }

    public void initializeSeederStatus() {
        m_seederStatus.setText(SEEDER_STATUS);
        m_seederStatus.setId(SEEDER_STATUS_ID);
        m_seederStatus.setFill(SEEDER_STATUS_COLOR);
        m_seederStatus.setFont(SEEDER_STATUS_FONT);
        m_seederStatus.setTextAlignment(TextAlignment.CENTER);
    }

    public void initializeSeederControls() {
        initializeSeederCloseButton();

        m_seederControls.getChildren().addAll(m_seederCloseButton);
        m_seederControls.setId(SEEDER_CONTROLS_ID);
        m_seederControls.setAlignment(Pos.TOP_RIGHT);
    }

    public void initializeSeederCloseButton() {
        m_image = new Image(SEEDER_CLOSE_BUTTON);
        m_seederCloseButtonImage.setImage(m_image);
        m_seederCloseButtonImage.setFitWidth(SEEDER_CLOSE_BUTTON_SIZE);
        m_seederCloseButtonImage.setFitHeight(SEEDER_CLOSE_BUTTON_SIZE);

        m_seederCloseButton.setId(SEEDER_CLOSE_BUTTON_ID);
        m_seederCloseButton.setGraphic(m_seederCloseButtonImage);
        m_seederCloseButton.setBackground(new Background(new BackgroundFill(Color.TRANSPARENT, CornerRadii.EMPTY, Insets.EMPTY)));
        m_seederCloseButton.setOnAction(handleCloseEvent());
        m_seederCloseButton.addEventHandler(MouseEvent.ANY, seederCloseButtonMouseEvent());
    }

    private EventHandler<? super MouseEvent> seederCloseButtonMouseEvent() {
        return (EventHandler<MouseEvent>) event ->
        {
            if (event.getEventType() == MouseEvent.MOUSE_ENTERED) {
                m_image = new Image(SEEDER_CLOSE_BUTTON_HOVERED);
                m_seederCloseButtonImage.setImage(m_image);
            } else if (event.getEventType() == MouseEvent.MOUSE_EXITED) {
                m_image = new Image(SEEDER_CLOSE_BUTTON);
                m_seederCloseButtonImage.setImage(m_image);
            }
        };
    }

    public void showSeederWindow() {
        m_stage.show();
        m_stage.toFront();
        m_stage.setAlwaysOnTop(true);
    }

    private EventHandler<ActionEvent> handleCloseEvent() {
        return event -> System.exit(0);
    }

    private void dragSeeder() {
        m_seederContainer.setOnMousePressed(event ->
        {
            xOffset = event.getSceneX();
            yOffset = event.getSceneY();
        });
        m_seederContainer.setOnMouseDragged(event ->
        {
            m_stage.setX(event.getScreenX() - xOffset);
            m_stage.setY(event.getScreenY() - yOffset);
        });
    }
}