Problem in reusing the declader slider variable in VBox

Question

There is a slider variable {color:#0000ff}specexpontLevel{color}. This variable is used 2 times in VBox content as per my requirement. But the VBox contents are not visble @ the runtime. If I call the variable only once in VBox then the contents are displayed. Without using VBox, if I reuse in the contents of scene also it is not displaying.
The NetBeans IDE is displaying the below runtime error
java.lang.IllegalArgumentException: illegal assignment of group.content: group=Group node=Slider
{color:#0000ff}*Does this mean the variable cannot be resued in the content? If so the concept of reusability is defeated. If it is intensionally included what is the justification behind it?*{color}
import javafx.scene.Scene;
import javafx.scene.text.Font;
import javafx.scene.text.Text;
import javafx.stage.Stage;
import javafx.scene.control.Slider;
import javafx.scene.layout.LayoutInfo;
import javafx.scene.layout.VBox;
var diffusespecconstLevel: Slider = Slider{
max: 2.0
min:0.0
value:0.7
width : 70
layoutInfo: LayoutInfo{ width: 70 minWidth: 70}
var {color:#0000ff}specexpontLevel{color} : Slider = Slider{
max: 20.0
min:0.0
value:5.0
width : 70
layoutInfo: LayoutInfo{ width: 70 minWidth: 70}
var surfaceLevel: Slider = Slider{
max: 2.5
min:0.0
value:1.0
width : 70
layoutInfo: LayoutInfo{ width: 70 minWidth: 70}
Stage {
title: "Hello World"
width: 250
height: 500
scene: Scene {
content: [
Text {
content: "Hello World! My First JavaFX program!"
x:0
y:12
font: Font {
name: "Arial"
size: 12
VBox {translateY : 20 content : [<font color="#0000ff">specexpontLevel</font>,diffusespecconstLevel,surfaceLevel, <font color="#0000ff">specexpontLevel</font>]}

Answer 1

Hello!
could you elaborate your answer please?
I have the same kind of problem in an application I am working on for now.
I have the application' scene content inside which I have a node whose id I set to "applicationContent" (this node is a group).
Upon clicking on menu buttons, I will remove the node having the "applicationContent" id from my application content and will insert another one having the same id.
The inserted node is generated on the fly upon clicking on the button.
Method below is executed only once and adds menu buttons to the left of my application.
Notice the action:function() method that calls the setContent(Node) method when the button is clicked.
  function insertMenuItems(): Void
        var elementCounter: Number = 0;
        var firstY: Number = 160;
        for(currentItem in menu)
            var currentButton:MenuButton = MenuButton
                text: currentItem.title;
                layoutX: 8;
                width: 182;
                layoutY: firstY + elementCounter * 40;
                action: function()
                    this.title = currentItem.title;
                    setContent(currentItem.getContent());
            insert currentButton into content;
            elementCounter++;
    }The setContent method is provided here below.
As you see, it removes the node having the "applicationContent" id and adds the one passed in parameter ("the new application content").
     * Sets the main content of the application.
     * <p>
     *  Each time a menu button gets clicked, the main content of the application
     *  will be replaced by the one attached to the <code>MenuButton</code>
     * </p>
    function setContent(applicationContent:Node):Void
        for(currentNode in content)
            if(currentNode.id.equals("ApplicationContent"))
                delete currentNode from content;
                break;
            applicationContent.layoutX = 300;
            applicationContent.layoutY = 500;
            insert applicationContent into content;
    }the "{code}insert applicationContent into content;{code}" line is the one producing the exception, even though, in the end, my content is correctly updated on screen.
exception happening at this specific line is the following:
Exception in trigger:
java.lang.IllegalArgumentException: illegal assignment of group.content: group=Group node=ApplicationContent [id=ApplicationContent]
at javafx.scene.Group$_SBECL.onChange(Group.fx:209)
at com.sun.javafx.runtime.location.SequenceVariable.notifyListeners(SequenceVariable.java:157)
at com.sun.javafx.runtime.location.SequenceVariable.setAsSequence(SequenceVariable.java:259)
at com.sun.javafx.runtime.location.SequenceVariable.set(SequenceVariable.java:222)
at com.sun.javafx.runtime.location.SequenceVariable.set(SequenceVariable.java:39)
at com.sun.javafx.runtime.location.Bindings$BijectiveBinding$2.onChange(Bindings.java:156)
at com.sun.javafx.runtime.location.AbstractLocation$1.onAction(AbstractLocation.java:220)
at com.sun.javafx.runtime.location.AbstractLocation$1.onAction(AbstractLocation.java:217)
at com.sun.javafx.runtime.location.AbstractLocation.iterateChildren(AbstractLocation.java:182)
at com.sun.javafx.runtime.location.AbstractLocation.invalidateDependencies(AbstractLocation.java:254)
at com.sun.javafx.runtime.location.SequenceVariable.notifyListeners(SequenceVariable.java:150)
at com.sun.javafx.runtime.location.SequenceVariable.replaceSlice(SequenceVariable.java:324)
at com.sun.javafx.runtime.location.SequenceVariable.insert(SequenceVariable.java:442)
at javafxapplication3.FixedRootScene.setContent(FixedRootScene.fx:139)
at javafxapplication3.FixedRootScene.setContent(FixedRootScene.fx:139)
at javafxapplication3.FixedRootScene$1.lambda(FixedRootScene.fx:109)
at javafxapplication3.FixedRootScene$1.lambda(FixedRootScene.fx:109)
at javafxapplication3.FixedRootScene$1.invoke(FixedRootScene.fx:106)
at javafxapplication3.FixedRootScene$1.invoke(FixedRootScene.fx:106)
at javafxapplication3.FixedRootScene$1.invoke(FixedRootScene.fx:106)
at javafxapplication3.FixedRootScene$1.invoke(FixedRootScene.fx:106)
at javafx.scene.control.Button.fire(Button.fx:50)
at com.sun.javafx.scene.control.ButtonBaseBehavior.mouseRelease(ButtonBaseBehavior.fx:78)
at com.sun.javafx.scene.control.caspian.AbstractButtonSkin$4.lambda(AbstractButtonSkin.fx:68)
at com.sun.javafx.scene.control.caspian.AbstractButtonSkin$4.invoke(AbstractButtonSkin.fx:68)
at com.sun.javafx.scene.control.caspian.AbstractButtonSkin$4.invoke(AbstractButtonSkin.fx:68)
at javafx.scene.Node.impl_processMouseEvent(Node.fx:1679)
at javafx.scene.Node.preprocessMouseEvent(Node.fx:1705)
at javafx.scene.Scene$MouseHandler.process(Scene.fx:665)
at javafx.scene.Scene$MouseHandler.process(Scene.fx:550)
at javafx.scene.Scene.impl_processMouseEvent(Scene.fx:368)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.fx:496)
at com.sun.javafx.tk.swing.SwingScene$SwingScenePanel.doMouseEvent(SwingScene.java:388)
at com.sun.javafx.tk.swing.SwingScene$SwingScenePanel.mouseReleased(SwingScene.java:408)
at java.awt.Component.processMouseEvent(Component.java:6134)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
at java.awt.Component.processEvent(Component.java:5899)
at java.awt.Container.processEvent(Container.java:2023)
at java.awt.Component.dispatchEventImpl(Component.java:4501)
at java.awt.Container.dispatchEventImpl(Container.java:2081)
at java.awt.Component.dispatchEvent(Component.java:4331)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4301)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3965)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3895)
at java.awt.Container.dispatchEventImpl(Container.java:2067)
at java.awt.Window.dispatchEventImpl(Window.java:2458)
at java.awt.Component.dispatchEvent(Component.java:4331)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
If yo ucould explain me why the exception fires, i'd be very happy ^^
Thank you very much in advance for your help!
Edited by: jerome_jadoulle on Jul 14, 2009 2:00 AM