Questions[javafx]

I am creating a login, it consists of entering a username and password, then when I click on validate, the Login closes and a new window opens (where I will include functions that I have not yet implemented)... but this new window has a logout button, how can I make clicking that button return me to Login?

I've already been looking for solutions, but everything seems too confusing, I've seen that I can load everything in the same Stage, just changing the Scene, but I see it as complex, I don't understand how it does it..., this is my code.

Main class

    package mainPack;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class mainC extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {

        Parent root = FXMLLoader.load(getClass().getResource("/GUIs/Login.fxml"));



        Scene scene = new Scene(root);
        primaryStage.setScene(scene);
        primaryStage.show();


    }

}

LoginController

package GUIs;

import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.event.ActionEvent;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.stage.Stage;

public class LoginController implements Initializable {

    /**
     * Initializes the controller class.
     */

    @FXML PasswordField txtPass;
    @FXML TextField txtUser;
    @FXML Label lblError;
    @FXML Label lblStatus;


    @FXML
    public void btnHandle(ActionEvent e) throws Exception{

        if(txtUser.getText().equals("Sistemas")  && txtPass.getText().equals("2019")){

            lblError.setOpacity(0);
            lblStatus.setText("Conectado.");

            Stage stage = new Stage();
            Parent root = FXMLLoader.load(getClass().getResource("/GUIs/Principal.fxml"));

            Scene escena = new Scene(root);
            stage.setScene(escena);
            stage.show();
//en esta linea, esconde el Stage del Login y carga el nuevo stage
            ( (Node) (e.getSource() ) ).getScene().getWindow().hide();

        }else{
            lblStatus.setText("Desconectado.");
            lblError.setOpacity(1);

        }


    }

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    

}

WindowPrincipalController (after login)

package GUIs;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;

/**
 * FXML Controller class
 *
 * @author VAPESIN
 */
public class PrincipalController implements Initializable {

    /**
     * Initializes the controller class.
     */

    @FXML
    public void cerrarSesHandle(ActionEvent e){

    }


    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    

}

Login.fxml

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

<?import java.net.URL?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.PasswordField?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.text.Font?>

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="493.0" styleClass="mainFxmlClass" xmlns="http://javafx.com/javafx/10.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="GUIs.LoginController">
    <stylesheets>
        <URL value="@login.css" />
    </stylesheets>
   <children>
      <Label layoutX="49.0" layoutY="71.0" prefHeight="46.0" prefWidth="52.0" text="Usuario" />
      <Label layoutX="49.0" layoutY="148.0" prefHeight="46.0" prefWidth="66.0" text="Contraseña" />
      <Button layoutX="145.0" layoutY="252.0" mnemonicParsing="false" onAction="#btnHandle" text="Validar" />
      <TextField fx:id="txtUser" layoutX="145.0" layoutY="82.0" />
      <PasswordField fx:id="txtPass" layoutX="145.0" layoutY="159.0" />
      <Label fx:id="lblError" layoutX="74.0" layoutY="301.0" opacity="0.0" prefHeight="46.0" prefWidth="345.0" text="Usuario o Contraseña incorrecta." textFill="RED">
         <font>
            <Font size="17.0" />
         </font>
      </Label>
      <Label fx:id="lblStatus" layoutX="101.0" layoutY="25.0" prefHeight="46.0" prefWidth="330.0" text="Desconectado" />
   </children>
</AnchorPane>

MainWindow.fxml

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

<?import java.net.URL?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.text.Font?>

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" styleClass="mainFxmlClass" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/10.0.1" fx:controller="GUIs.PrincipalController">
    <stylesheets>
        <URL value="@principal.css" />
    </stylesheets>
   <children>
      <Label layoutX="167.0" layoutY="77.0" prefHeight="103.0" prefWidth="271.0" text="Bienvenido">
         <font>
            <Font size="53.0" />
         </font>
      </Label>
      <Button layoutX="438.0" layoutY="345.0" mnemonicParsing="false" onAction="#cerrarSesHandle" prefHeight="25.0" prefWidth="142.0" text="Cerrar sesión" />
   </children>
</AnchorPane>

When clicking on close, I would like it to return me to the Login.

I have a JavaFx application whose main window has several buttons, I have assigned actions to the keys ENTERand ESCAPEwith a code like this:

scene.setOnKeyReleased((KeyEvent keyEvent) -> {
    System.out.println(" -> " + keyEvent.getCode().toString( )); // trace

    if(keyEvent.getCode() == ENTER) {
        // some action here
    }
    if(keyEvent.getCode() == ESCAPE) {
        // some action here
    }
});

The necessary imports are:

import javafx.scene.input.KeyEvent;
import static javafx.scene.input.KeyCode.ENTER;
import static javafx.scene.input.KeyCode.ESCAPE;

I have observed (in Windows) that if the "space bar" is pressed, the keys of the program are successively pressed, I would like to avoid this, that is, leave the pressing of the space key without effect .

Note: In the example code I added a line to trace the key pressed, however the space bar key press is not captured.

Edit: SOLUTION

Building on Gorjesys answer which allows me to detect the key (space bar). The event is marked as consumed to avoid the behavior implemented by default. So the previous code would be:

// importaciones
import javafx.scene.input.KeyEvent;
import static javafx.scene.input.KeyCode.ENTER;
import static javafx.scene.input.KeyCode.ESCAPE;
import static javafx.scene.input.KeyCode.SPACE;

// ...

scene.setOnKeyReleased((KeyEvent keyEvent) -> {
    System.out.println(" -> " + keyEvent.getCode().toString( )); // trace

    if(keyEvent.getCode() == ENTER) {
        // some action here
    }
});
scene.addEventFilter(KeyEvent.KEY_PRESSED, (KeyEvent keyEvent) -> {
    if (keyEvent.getCode() == ESCAPE) {
        // some action here
    }
    if (keyEvent.getCode() == SPACE) {
        keyEvent.consume();
        // NOTE: Marks this Event as consumed to avoid the
        // default behaviour
    }
});

Note: I have moved the detection of the ESCAPE key because sometimes it is not detected by the method I was using ( see question ).

I am using a PopOver that contains a TextField and is displayed when the user clicks on the imageView of a CustomTextField. When I type inside the inner TextField, everything goes fine until I enter a stressed vowel, which to my surprise is picked up by the outer TextField instead of the inner one.

I show pictures of what happens, whenpopover.show(imageView)

When the popover is shown from a button there is no problempopover.show(button)

I don't know, it seems to be a bug. If anyone has any ideas as to why this is happening I would appreciate any help. Thank you

EDIT: Here I reproduce an example of code in which the effect that I mention is produced, when you introduce a vowel with a tilde in the internal textfield, it does not appear in the internal one, but it does in the external one.

public class PopOverTest extends Application {

    @Override
    public void start(Stage primaryStage) {

        CustomTextField externo = new CustomTextField();
        ImageView imgView = new ImageView(new Image("test/image.png"));
        externo.setLeft(imgView);

        CustomTextField interno = new CustomTextField();

        PopOver popOver = new PopOver();
        popOver.setContentNode(interno);

        imgView.setOnMouseClicked(e -> {
            popOver.show(imgView);

        });


        StackPane root = new StackPane();
        root.getChildren().add(externo);

        Scene scene = new Scene(root, 300, 250);

        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}

I want to detect when the mouse pointer hovers over a control. In CSSwould do with .miControl:hover{...}, but how do you do it in JavaFX code?

I'm detecting the change of a button group's value with a Listener. If there is nothing selected I put the previous value before the change, but this causes me to call back to ListenerHow can I avoid it?

The code is:

toggleGroup.selectedToggleProperty().addListener(
    (ObservableValue<? extends Toggle> arg0, Toggle oldValue, Toggle newValue) -> {
        if (toggleGroup.getToggles().indexOf(toggleGroup.getSelectedToggle()) == -1) {                
                    toggleGroup.selectToggle(oldValue); // esto provoca rellamada al Listener
                }
            }
        );