Exemplo com Window Controller

TelaExemploController.java

import WindowController;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.scene.control.Menu;
import javafx.scene.control.MenuBar;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Region;
import javafx.scene.layout.StackPane;
import javafx.util.Duration;

/**
 * FXML Controller class
 *
 * @author Fernando Andrauss
 */
public class TelaExemploController extends WindowController {

    /*
        Para chamar a tela use um dos métodos abaixo:
        
        -> Janela com botões: de maximizar, minimizar, fechar
        TelaExemploController().show(pai); 
    
         -> Janela com botões: de maximizar, minimizar, fechar e em modal
        TelaExemploController().showModal(pai);
        
        -> Dialog com botões: fechar e em modal
        TelaExemploController().showAsDialg(pai);
        
        -> Dialog sem decoração de janela e em modal
        -> transparente: se true o fundo da janela fica tranparente, false fundo normal
        TelaExemploController().showUndecorated(pai, tranparente?);
    
        Métodos Adicionais:
        TelaExemploController()
                .setTitulo("Frame de Cadastro")           -> Use setTitulo para definir o títuo da janela
                .setIcone(new Image("caminho_da_imagem")) -> Use setIcone para definir o ícone da janela
                .show(pai)
                .maximize()                               -> Use maximize para Maximizar a janela
                .minimize()                               -> Use minimize para minimizar
                .telaCheia();                             -> Use telaCheia para entrar em tela cheia
                .sairTelaCheia();                         -> Use sairTelaCheia para sair da tela cheia
    
    
     */
    @FXML
    private AnchorPane pane;

    @FXML
    private TextField tfTitulo;

    /**
     * Sobreescrevendo o método que define o layout
     *
     * @return
     */
    @Override
    public String getFXML() {
        return "/layout/tela_exemplo.fxml";

    }

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // Inicialização de componentes
        System.out.println("INITIALIZE " + getClass().getName());
    }

    /**
     * Ações definidas no layout
     */
    @FXML
    void ActionShow() {
        new TelaExemploController()
                .setTitulo(tfTitulo.getText())
                .show(getWindow())
                .telaCheia();
    }

    @FXML
    void ActionShowAsDialog() {
        new TelaExemploController()
                .setTitulo(tfTitulo.getText())
                .showAsDialg(getWindow());
    }

    @FXML
    void ActionShowModal() {
        new Tela_exemplo_2Controller()
                .setTitulo(tfTitulo.getText())
                .showModal(getWindow());
    }

    @FXML
    void ActionShowUndecorated() {
//        new TelaExemploController()
//                .setTitulo(tfTitulo.getText())
//                .showUndecorated(getWindow(), false);

        new WindowController() {
            @Override
            public Region getRootPane() {
                BorderPane pane = new BorderPane();

                pane.setPrefSize(300, 300);

                MenuBar menu = new MenuBar();
                menu.getMenus().add(new Menu("Arquivo"));
                menu.getMenus().add(new Menu("Editar"));

                pane.setTop(menu);

                StackPane paneCenter = new StackPane();
                paneCenter.setStyle("-fx-background-color: linear-gradient(aqua, blue);");

                pane.setCenter(paneCenter);

                return pane;
            }

            @Override
            public void initialize(URL location, ResourceBundle resources) {

            }
        }.show(getWindow())
                .altura(600)
                .largura(800);
    }

    @FXML
    void ActionShowUndecoratedTransparent() {
        new TelaExemploController()
                .setTitulo(tfTitulo.getText())
                .showUndecorated(getWindow(), true);
    }

    @FXML
    private void Close() {
        getWindow().close();
    }

    @Override
    public void onShow() {
    }

}











// tela_exemplo.fxml

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

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.effect.DropShadow?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.StackPane?>


<StackPane xmlns="http://javafx.com/javafx/8.0.60" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <AnchorPane  id="AnchorPane" fx:id="pane" prefHeight="400.0" prefWidth="600.0" style="-fx-background-color: white; -fx-border-color: cyan;">
         <children>
            <Button layoutX="31.0" layoutY="34.0" mnemonicParsing="false" onAction="#ActionShow" prefHeight="38.0" prefWidth="76.0" style="-fx-base: green;" text="show" />
            <Button layoutX="510.0" layoutY="360.0" mnemonicParsing="false" onAction="#Close" prefHeight="26.0" prefWidth="76.0" style="-fx-base: red;" text="Fechar" />
            <Button layoutX="121.0" layoutY="34.0" mnemonicParsing="false" onAction="#ActionShowModal" prefHeight="38.0" prefWidth="107.0" style="-fx-base: green;" text="showModal" />
            <Button layoutX="247.0" layoutY="34.0" mnemonicParsing="false" onAction="#ActionShowAsDialog" prefHeight="38.0" prefWidth="107.0" style="-fx-base: green;" text="showAsDialog" />
            <Button layoutX="31.0" layoutY="84.0" mnemonicParsing="false" onAction="#ActionShowUndecorated" prefHeight="38.0" prefWidth="328.0" style="-fx-base: green;" text="showUndecorated" />
            <Button layoutX="31.0" layoutY="134.0" mnemonicParsing="false" onAction="#ActionShowUndecoratedTransparent" prefHeight="38.0" prefWidth="328.0" style="-fx-base: green;" text="showUndecorated(transparent)" />
            <TextField fx:id="tfTitulo" layoutX="31.0" layoutY="188.0" prefHeight="25.0" prefWidth="328.0" promptText="Titulo da Janela" />
         </children>
         <effect>
            <DropShadow color="#00bfff" height="100.0" radius="49.5" width="100.0" />
         </effect>
      </AnchorPane>
   </children>
   <padding>
      <Insets bottom="50.0" left="50.0" right="50.0" top="50.0" />
   </padding>
</StackPane>