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How to resize accordion after removing a pane in JavaFX

Im working on a small JavaFX project. In one of my scenes, I want to dynamically add and remove a custom component I implemented, which extends from TitledPane, to respectively from an Accordion. This works all well and good, but after removing the pane from the Accordion the damn thing won't resize immidately, but only after I click somewhere on the gui. I prepared the following GIF to visualize the problem to you.
Can someone tell me why the accordion only resizes after I clicked somewhere on the gui interface and not immidiately? I mean auto resizing doesn't seem to be a problem, it just won't trigger...can someone tell me why that is the case? Maybe this is obvious, but I am not very familiar with JavaFX, so I am really stuck here. I also observed a similar behavior with other component, so maybe I am missing something fundamentally here.
UPDATE
Ok I created a minimal example for you to reproduce my problem. You can clone the repository on GitHub javafx-demo and try it out yourself. Doing this I noticed, that the Accordion resizes only if I click on it and not when I click anywhere else on the gui.
UPDATE 1
I simplified the example further. You can find the example in the GitHub repository above or see the code below:
App
public class App extends Application {
#Override
public void start(Stage stage) throws IOException {
FXMLLoader fxmlLoader = new FXMLLoader(App.class.getResource("parentView.fxml"));
Scene scene = new Scene(fxmlLoader.load(), 640, 480);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch();
}
}
ParentController
public class ParentController {
#FXML
private Accordion accordion;
public void onAddAction() {
var itemControl = new ItemControl();
EventHandler<ActionEvent> removeEventHandler = event -> {
accordion.getPanes().remove(itemControl);
};
itemControl.setOnRemoveProperty(removeEventHandler);
accordion.getPanes().add(itemControl);
}
}
Parent View
<StackPane xmlns="http://javafx.com/javafx/16"
xmlns:fx="http://javafx.com/fxml/1"
fx:controller="org.example.ParentController">
<Group StackPane.alignment="CENTER">
<VBox>
<Accordion fx:id="accordion"/>
<Button onAction="#onAddAction" text="Add"/>
</VBox>
</Group>
</StackPane>
ItemControl
public class ItemControl extends TitledPane {
private final UUID id = UUID.randomUUID();
private final ObjectProperty<EventHandler<ActionEvent>> onRemoveProperty = new SimpleObjectProperty<>();
#FXML
private Button removeButton;
public ItemControl() {
FXMLLoader fxmlLoader = new FXMLLoader(ItemControl.class.getResource("itemControl.fxml"));
fxmlLoader.setRoot(this);
fxmlLoader.setController(this);
try {
fxmlLoader.load();
} catch (IOException e) {
e.printStackTrace();
}
}
#FXML
public void initialize() {
removeButton.onActionProperty().bind(onRemoveProperty);
}
public void setOnRemoveProperty(EventHandler<ActionEvent> onRemoveProperty) {
this.onRemoveProperty.set(onRemoveProperty);
}
// equals and hashCode omitted for brevity (id instance variable is used as identifier)
}
ItemControl FXML
<fx:root type="javafx.scene.control.TitledPane" xmlns="http://javafx.com/javafx/16" xmlns:fx="http://javafx.com/fxml/1">
<VBox>
<Button fx:id="removeButton" text="Remove"/>
</VBox>
</fx:root>

The behavior is a bug in AccordionSkin. The technical reason is that it keeps internal references to the current and previous expanded pane - both used in calculating the min/pref height - which are not updated correctly on removing the expanded pane. A fix would be to null those references if the panes are no longer part of the accordion, f.i. from the skin's listener to the panes list.
There is no clean way to work around this because all involved fields/methods are private - if we are allowed to go dirty, though, we can hack around the bug with reflection.
The basics:
extend AccordionSkin and let our accordion use the extended version
in the skin, override both computeMin/Pref/Height to check/fix the references before returning super
check: the panes should be contained in the accordion's panes
fix: if not, set the reference to null
Notes:
the reflective access to internal fields requires that the package is opened at runtime
the usual beware: tweaking/relying on implementation internals is highly version dependent and might/will break eventually
FXUtils is my local utility class for reflection, you have to replace it with your own implementation
The code:
public class SimpleLayoutAccordionOnRemove extends Application {
/**
* AccordionSkin that hacks the broken layout after remove of expanded pane.
*/
public static class HackedAccordionSkin extends AccordionSkin {
public HackedAccordionSkin(Accordion control) {
super(control);
}
#Override
protected double computeMinHeight(double width, double topInset, double rightInset,
double bottomInset, double leftInset) {
checkPaneFields();
return super.computeMinHeight(width, topInset, rightInset, bottomInset, leftInset);
}
#Override
protected double computePrefHeight(double width, double topInset, double rightInset,
double bottomInset, double leftInset) {
checkPaneFields();
return super.computePrefHeight(width, topInset, rightInset, bottomInset, leftInset);
}
private void checkPaneFields() {
checkPaneField("previousPane");
checkPaneField("expandedPane");
}
/**
* Check if the pane referenced by the field with the given name is contained
* in the accordion's panes and sets it to null if not.
*/
private void checkPaneField(String fieldName) {
TitledPane prev = (TitledPane) FXUtils.invokeGetFieldValue(AccordionSkin.class, this, fieldName);
if (!getSkinnable().getPanes().contains(prev)) {
FXUtils.invokeSetFieldValue(AccordionSkin.class, this, fieldName, null);
}
}
}
private Parent createContent() {
Accordion accordion = new Accordion() {
#Override
protected Skin<?> createDefaultSkin() {
return new HackedAccordionSkin(this);
}
};
Button add = new Button("add");
add.setOnAction(e -> {
addTitledPane(accordion);
});
VBox accBox = new VBox(accordion, add);
StackPane content = new StackPane(new Group(accBox));
return content;
}
int count;
private void addTitledPane(Accordion accordion) {
TitledPane pane = new TitledPane();
pane.setText("Pane " + count++);
Button remove = new Button("remove");
remove.setOnAction(e -> {
accordion.getPanes().remove(pane);
});
VBox box = new VBox(remove);
pane.setContent(box);
accordion.getPanes().add(pane);
}
#Override
public void start(Stage stage) throws Exception {
stage.setScene(new Scene(createContent(), 600, 400));
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}

How to create an FXML handler that accepts parameters?

I am developing a small, fake, Mail Client in JavaFXML.
It offers a Listview with messages written on a txt file, a TextArea which prints selected message and some buttons.
Here's an Image of the Main View: https://ibb.co/iKN2rm
I already took care of "New Message" Button, which is launching a new FXML View and works well.
Here's an Image of the "New_Message" View: https://ibb.co/hQf5Bm
Now I'm trying to implement the "Reply" button, which should launch the same View as before (New Message) but set on all three TextFields strings taken from the Main View, such as Message's text, recipient and Message Argument.
Below the New Message Button Handler:
private void handle_new(ActionEvent event) {
try {
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("/Client/Resources/new_utente1.fxml"));
Parent root1 = (Parent) fxmlLoader.load();
Stage stage = new Stage();
stage.setTitle("New Message");
stage.setScene(new Scene(root1));
stage.show();
} catch (Exception ecc) {
System.out.println("ERROR: " + ecc.getMessage());
}
}
I tried to implement the handle_reply method, but I'm not able to add parameters because FXML file won't find the method if I do so.
Below a small part of the FXML file:
<TextArea fx:id = "testo" editable="false" layoutX="283.0" layoutY="53.0" prefHeight="450.0" prefWidth="490.0" promptText="Select a message and it will be displayed here..." />
<Button id="nuovo" layoutX="46.0" layoutY="521.0" onAction = "#handle_new" mnemonicParsing="false" prefHeight="25.0" prefWidth="173.0" text="New Message" />
<Button id="reply" layoutX="283.0" layoutY="521.0" onAction = "#handle_reply" mnemonicParsing="false" prefHeight="25.0" prefWidth="132.0" text="Reply" />
My question is: How do I implement the "handle_reply" method as described before?
Thank you

Create a Controller class
then connect this class to your view
private void handle_new(ActionEvent event) {
try {
FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("/Client/Resources/new_utente1.fxml"));
Parent root1 = (Parent) fxmlLoader.load();
CController ctr = fxmlLoader.getController();
ctr.setLabelText("asdsad");
Stage stage = new Stage();
stage.setTitle("New Message");
stage.setScene(new Scene(root1));
stage.show();
} catch (Exception ecc) {
System.out.println("ERROR: " + ecc.getMessage());
}
}
and in your Controllers you'll do
public class CController implements Initializable {
#FXML TextArea testo;
#Override
public void initialize(URL location, ResourceBundle resources) {}
public void setLabelText(String text){testo.setText(text);}
}

Unfortunately it's not possible to use handlers with parameters. You should use different handler in each case.
Had this problem some time ago too. As a solution you could perform small refactoring to minimize code duplicating.
And if you know javascript you can play with this instead of using java handlers: https://docs.oracle.com/javase/8/javafx/api/javafx/fxml/doc-files/introduction_to_fxml.html#scripting
Edit: also you can check this answer: https://stackoverflow.com/a/37902780/5572007 (pretty the same)

FXMLLoader load time in JDK 8u92

In my JavaFX application I have to load many fxml files (200+) in the same time. I have decided to load them in background Task just like in https://stackoverflow.com/a/34878843 answear. Everything works fine (load time was acceptable) until JDK update. Newest version of JDK lengthened load time 3-4 times.
I have checked previous JDK releases and that problem appears from the JDK 8u92.
To test that issue I created new simple JavaFX FXML Application in Netbeans 8.1 and use only generated classes and fxml. Creating view from code works fine.
Application class:
public class FXMLLoaderTest extends Application {
private static Executor ex = Executors.newCachedThreadPool();
//private static Executor ex = Executors.newFixedThreadPool(400);
//private static Executor ex = Executors.newSingleThreadExecutor();
#Override
public void start(Stage stage) throws Exception {
VBox box = new VBox();
ScrollPane root = new ScrollPane(box);
Button b = new Button("GENERATE");
b.setOnAction(e -> {
IntStream.range(0, 1000).forEach(i -> {
Task<Parent> task = new Task<Parent>() {
#Override
protected Parent call() throws Exception {
FXMLLoader loader = new FXMLLoader(getClass().getResource("FXMLDocument.fxml"));
Parent root = null;
try {
root = loader.load();
} catch (IOException ex) {
Logger.getLogger(Loader.class.getName()).log(Level.SEVERE, null, ex);
}
// StackPane root= new StackPane();
// Button click = new Button("Click");
// root.setPrefSize(300, 300);
// root.getChildren().add(click);
return root;
}
};
task.setOnSucceeded(ev -> {
final Parent parent = task.getValue();
box.getChildren().add(parent);
});
task.setOnFailed(ev -> task.getException().printStackTrace());
ex.execute(task);
});
});
box.getChildren().add(b);
Scene scene = new Scene(root, 400, 500);
stage.setScene(scene);
stage.show();
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}
FXMLDocument.fxml
<AnchorPane id="AnchorPane" prefHeight="200" prefWidth="320" xmlns:fx="http://javafx.com/fxml/1" fx:controller="fxmlloader.FXMLDocumentController">
<children>
<Button layoutX="126" layoutY="90" text="Click Me!" onAction="#handleButtonAction" fx:id="button" />
<Label layoutX="126" layoutY="120" minHeight="16" minWidth="69" fx:id="label" />
</children>
</AnchorPane>
FXMLDocumentController.java
public class FXMLDocumentController implements Initializable {
#FXML
private Label label;
#FXML
private void handleButtonAction(ActionEvent event) {
System.out.println("You clicked me!");
label.setText("Hello World!");
}
#Override
public void initialize(URL url, ResourceBundle rb) {
// TODO
}
}
I have tested this on several computers and result was always the same. On JDK 8u91 fxml files load fast. I have checked release note of 8u92 and I haven't found any changes in FXMLLoader class.
Has anybody encounter this issue? Mayby I am doing something wrong then please correct me.

JavaFX BorderPane multi FXML space arrangement and transition effect

i want to design a GUI that contains BorderPane in the top of the container there is a MenuBar, in the left of the container there is a Acordion with different buttons that change the content of the center of the container for diferent FXML files, someting like the desktop app of Spotiffy
i got a working prototipe and it looks like this
the change in FXML happens and the buttos respont very well, the problem i have is that the FXML that fill the center part of the BoderPane doesn't auto rize and if is to big parts of the FXML doesn't show and if the FXML is smaller that the space left for the center part stays of the same small size and left alot of space with nothing
this is my code for the calling of the new FXML
public void lanzaUno(){
try {
// load first FXML
FXMLLoader loader = new FXMLLoader();
loader.setLocation(Coordinador.class.getResource(
"VistaControlador/Usuario/Uno.fxml"));
/*i put the AnchorPane inside of a
ScrollPane for the desire funcionality of alot
of vertical space for many nodes in a single FXML file
*/
ScrollPane unoAnchorPane = (ScrollPane) loader.load();
UnoController controller = loader.getController();
//example method for passing variables to the FXML controler
controller.pasoPrincipal(this, primaryStage, "Rhutt");
//puts the FXML in the center of the BorderPane
rootLayout.setCenter(unoAnchorPane);
//this if for trying to accommodate the content en the BorderPane
BorderPane.setAlignment(unoAnchorPane, Pos.TOP_LEFT);
} catch (IOException e) {
e.printStackTrace();
}
}
my first cuestion is what is the thing i am missing in the calling of the FXML for the contents of this ocupy the space available in the BorderPane?
my secon cuestion regards the change of FXML, when i pass fron one to another the change in the BorderPane is in a instant and looks very bad is there a way for making the transicion like one where the content of a FXML that is call push the content of the FXML in the center?, it doesn't have to be very elaborated just make the transition a little better
EDIT
i got a cordinator class where i send and recive parameters for all the FXML and where i declare the methods of calling new FXML, so i have a cordinator class, a FXML root with its controller and two FXML and its controllers with different things in each one, this two FXML are the ones that change in the BorderPane center of the root
this is the coordinator class
//Variables
private Stage primaryStage;
private BorderPane rootLayout;
/**
* launh
* #param primaryStage
*
*/
#Override
public void start(Stage primaryStage) throws Exception{
// Inicializa la escena
this.primaryStage = primaryStage;
this.primaryStage.setTitle("Login");
this.primaryStage.centerOnScreen();
//star method
iniLogin();
}
/**
*load the root scene
*/
public void iniLogin(){
try {
// Carga el loader.
FXMLLoader loader = new FXMLLoader();
loader.setLocation(com.aohys.rehabSys.MVC.Coordinador.class.getResource(
"VistaControlador/Pricipal/Principal.fxml"));
rootLayout = (BorderPane) loader.load();
//the root scene
Scene scene = new Scene(rootLayout);
primaryStage.setScene(scene);
// Da acceso al programa principal.
PrincipalController controller = loader.getController();
controller.pasoPrincipal(this, primaryStage);
primaryStage.centerOnScreen();
// Muesta la escena,
primaryStage.show();
} catch (IOException e) {
e.printStackTrace();
}
}
after this method there are two identical methods like the one at the beginning where i call the 2 changing FXML call LanzaUno, LanzaDos
this is my rood FXML controler
public class PrincipalController implements Initializable {
//variable of the coordinator class
private Coordinador cordi;
private Stage stage;
/**
* method for passing parameters to the FXML
* #param cordi
* #param stage
*/
public void pasoPrincipal(Coordinador cordi, Stage stage) {
this.cordi = cordi;
this.stage = stage;
}
//FXML in root
#FXML private Button btt1;
#FXML private Button btt2;
#FXML public static StackPane stackPane;
/**
* Initializes the controller class.
*/
#Override
public void initialize(URL url, ResourceBundle rb) {
//Call the firts FXML
btt1.setOnAction((evento)->{
cordi.lanzaUno();
});
//Call the second FXML
btt2.setOnAction((evento)->{
cordi.lanzaDos();
});
}
for the moment the controllers on the two FXML dont do anything

You should read up on Adam Bien's AfterburnerFX library for managing dependency injection and controllers in your application. It has changed my life. :)
For transitions, I use this code. It is a nice fade-out/fade-in from one screen to the next. In this case, stackPane is a StackPane in the center of your BorderPane defined in your FXML.
Here is a simple FXML with the aforementioned stackPane:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.text.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<BorderPane fx:id="borderPane" minHeight="-Infinity" minWidth="-Infinity" prefHeight="768.0" prefWidth="1280.0" xmlns="http://javafx.com/javafx/8.0.40" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.tada.gui.tada.TadaPresenter">
<center>
<StackPane fx:id="stackPane" minHeight="-Infinity" minWidth="-Infinity" prefHeight="240.0" prefWidth="320.0" BorderPane.alignment="CENTER" />
</center>
</BorderPane>
And the setScreen method that changes to the new one passed in:
/**
* Set Screen
*
* #param view
* #return boolean
*/
public boolean setScreen(Parent view) {
final DoubleProperty opacity = stackPane.opacityProperty();
if (!stackPane.getChildren().isEmpty()) { //if there is more than one screen
Timeline fade = new Timeline(
new KeyFrame(Duration.ZERO, new KeyValue(opacity, 1.0)),
new KeyFrame(new Duration(TRANSITION_TIMER), new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent t) {
stackPane.getChildren().remove(0); //remove the displayed screen
stackPane.getChildren().add(0, view); //add the screen
Timeline fadeIn = new Timeline(
new KeyFrame(Duration.ZERO, new KeyValue(opacity, 0.0)),
new KeyFrame(new Duration(TRANSITION_TIMER), new KeyValue(opacity, 1.0)));
fadeIn.play();
}
}, new KeyValue(opacity, 0.0)));
fade.play();
} else {
stackPane.setOpacity(0.0);
stackPane.getChildren().add(view); //no one else been displayed, then just show
Timeline fadeIn = new Timeline(
new KeyFrame(Duration.ZERO, new KeyValue(opacity, 0.0)),
new KeyFrame(new Duration(TRANSITION_TIMER), new KeyValue(opacity, 1.0)));
fadeIn.play();
}
return true;
}
You'll also need this in your controller...
private static final double TRANSITION_TIMER = 200;
EDIT:
I tried to put together a very basic "application". It is rudimentary, but I think it does a good job of illustrating the use of AfterburnerFX and the screen fade transition. There is a lot more to AfterburnerFX. I just used the view switching without the dependency injection, which is very important when you start wanting to work on objects in your application. Also, property binding is very important for a good UX. Anyway, Here is a link to my example on GitHub.

javafx set parent borderpane to null

i have 2 fxml
FXML A:
it contains borderpane with ID fx:id="UnitBorderPane"
FXML B:
it contains anchorpane with ID fx:id="UnitForm"
i load the "FXML B" at borderpane A on the left side
FXMLLoader loader = new
FXMLLoader(getClass().getResource("/projectname/unit/UnitForm.fxml"));
Pane pane = (Pane) loader.load();
UnitBorderPane.setLeft(pane);
it is kind of fxml form, so we have a button with action
<Button layoutX="102.0" layoutY="169.0" mnemonicParsing="false" onAction="#saveUnit" text="Save" />
how to hide that FXML A BorderPane left?
#FXML
private void saveUnit(ActionEvent event) {
BorderPane borpane = (BorderPane)UnitForm.getParent().lookup("#UnitBorderPane");
borpane.setLeft(null);
}
this code not work, the borpane variable is null so i cannot set the borderPane FXML A Left to null.

I think it should just be
BorderPane borpane = (BorderPane)UnitForm.getParent();
However, none of this feels very robust; for example if you decide to change the layout structure at all you will likely have a lot of code to change in various classes. I would add a property to the controller for UnitForm.fxml that you can observe from the controller for UnitBorderPane. Something like:
public class UnitFormController { // your actual class name may differ....
private final BooleanProperty saved = new SimpleBooleanProperty();
public BooleanProperty savedProperty() {
return saved ;
}
public final boolean isSaved() {
return savedProperty().get();
}
public final void setSaved(boolean saved) {
savedProperty().set(saved);
}
// other code as you already have...
#FXML
private void saveUnit() {
setSaved(true);
}
// ...
}
Then you do
FXMLLoader loader =
new FXMLLoader(getClass().getResource("/projectname/unit/UnitForm.fxml"));
Pane pane = (Pane) loader.load();
UnitFormController controller = loader.getController();
controller.savedProperty().addListener((obs, wasSaved, isNowSaved) -> {
if (isNowSaved) {
UnitBorderPane.setLeft(null);
}
});
UnitBorderPane.setLeft(pane);
Now the management of the UnitBorderPane is all in one place, instead of being split over two controllers, and there are no lookups (which are not robust). The controller for the UnitForm just sets a property and lets the other controller respond as it sees fit.