Could someone explain how node 'lookup' works ?

Question

Or more specifically the difference between pre 1.2 and 1.2 ? And now correct usage..
My application was quite happily using lookups.
- Assigning an id, including the nodes in the scene content at creation time. Looking them up, getting the address and then manipulating them
After the 1.2 upgrade they do not work at all (no changes) i.e. a null address after lookup
I did discover, however, that now in 1.2 if I created a new 'dynamic/on the fly' node with an id and then inserted it into the scene content later - hey presto it could be found.
So - what happened ?
And what is the correct procedure ?
Anyone else have this problem and can anyone help explain why this occurred ?
And technically (flow wise ?) how this (the id assignment, scene injection, lookup) works in FX ?
It appears to me that pre-created (or static[?]) approach is now broken and that only new post node (dynamic[?]) creation id and lookup works.
Cheers
ScottyB

Answer 1

Hi PhiLho,
Thanks for your patience and help.
I think it must be to do with CustomNodes as content then. Also content within content which does not mentioned directly in the mainScene.
I stripped down my application into some bare example - its not fancy as its hacked to death - but maybe it might explain what I am 'assuming' wrongly.
As I said before this was working in 1.1.
I probably have done something blazingly obviously wrong - but an explanition of why and how to do this correctly would be great.
When the button is hit: the print out is as follows
****LEFT PANEL****
mainSceneId: MainScene [id=mainSceneId]
LeftPanel: null
Left Movie01: null
backgroundRectangle: null
mainSceneId: MainScene [id=mainSceneId]
LeftPanel: null
****RIGHT PANEL****
mainSceneId: MainScene [id=mainSceneId]
RightPanel: MovieButtonPanel [id=rightPanelId]
Right Movie01: null
mainSceneId: MainScene [id=mainSceneId]
RightPanel: nullCode follows:
Main.fx
package testbed.test03;
import javafx.scene.Scene;
import javafx.stage.Stage;
var mainScene = MainScene {
    id: "mainSceneId"
public def myStage = Stage {
    title: "DynaButtons"
    width: 400
    height: 400
    scene: Scene {
        content: [mainScene]
function run(): Void {
}MainScene.fx
package testbed.test03;
import javafx.scene.CustomNode;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.shape.Rectangle;
import javafx.scene.paint.Color;
import javafx.scene.control.Button;
public class MainScene extends CustomNode {
    var leftPanel = MovieButtonPanel {
        id: "leftPanelId"
    var rightPanel = MovieButtonPanel {
        id: "rightPanelId"
        translateX: 210
    def button =   Button {
            translateX: 100
            translateY: 300
            text: "Press Me"
            action: function() {
                println("****LEFT PANEL****");
                // lookup mainSceneId
                var myNode:Node = Main.myStage.scene.lookup("mainSceneId");
                println("mainSceneId: {myNode}");
                // lookup Left Panel
                myNode = Main.myStage.scene.lookup("leftPanelId");
                println("LeftPanel: {myNode}");
                // lookup Movie01 Button
                myNode = Main.myStage.scene.lookup("Movie01");
                println("Left Movie01: {myNode}");
                // lookup background Rectangle
                myNode = Main.myStage.scene.lookup("backgroundRectangle");
                println("backgroundRectangle: {myNode}");
                // lookup mainSceneId
                myNode  = Main.myStage.scene.lookup("mainSceneId");
                println("mainSceneId: {myNode}");
                // lookup Left Panel from inside mainSceneID contents
                var myInternalNode:Node = myNode.lookup("leftPanelId");
                println("LeftPanel: {myInternalNode}");
                println("****RIGHT PANEL****");
                insert rightPanel into Main.myStage.scene.content;
                // lookup mainSceneId
                myNode = Main.myStage.scene.lookup("mainSceneId");
                println("mainSceneId: {myNode}");
                // lookup Left Panel
                myNode = Main.myStage.scene.lookup("rightPanelId");
                println("RightPanel: {myNode}");
                // lookup Button
                myNode = Main.myStage.scene.lookup("Movie01");
                println("Right Movie01: {myNode}");
                // lookup mainSceneId
                myNode  = Main.myStage.scene.lookup("mainSceneId");
                println("mainSceneId: {myNode}");
                // lookup Left Panel from inside mainSceneID contents
                myInternalNode = myNode.lookup("RightPanelId");
                println("RightPanel: {myInternalNode}");
    override public function create() : Node {
        return Group {
            content: [
                Rectangle {
                    id: "backgroundRectangle"
                    width: 400
                    height: 400
                    fill:Color.WHITE
                leftPanel,button
}MovieButtonPanel.fx
package testbed.test03;
import javafx.scene.CustomNode;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.layout.VBox;
import javafx.scene.shape.Rectangle;
import javafx.scene.paint.Color;
public class MovieButtonPanel extends CustomNode {
    var movies: String[] = ["Movie01","Movie02","Movie03","Movie04","Movie05"];
    def rect = Rectangle {
            width: 200, height: 300
            fill: Color.GRAY
    def movieButtons:MovieButton[] = bind for( movie in movies){
        MovieButton {
            id: movie
            movie: movie
            translateX: 20
    var listView = VBox {
        spacing: 10
        content: bind movieButtons
    override function create() : Node {
         Group {
            content: [rect,listView]
}MovieButton.fx
package testbed.test03;
import javafx.scene.CustomNode;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.scene.text.Text;
import javafx.scene.text.TextOrigin;
import javafx.scene.text.Font;
public class MovieButton extends CustomNode {
    public-init var movie: String;
    def theText = Text {
            font : Font {
                size: 12
       textOrigin: TextOrigin.TOP
        fill: Color.WHITE
        content: bind movie
    def theRect:Rectangle = Rectangle {
        fill: Color.BLACK
        width: 80
        height: 20
    override public function create() : Node {
        var buttonGroup = Group {
            content: [
                theRect,
                theText
        return buttonGroup;
}