Determine size of component at runtime

Question

I'm trying to build a Paginagion component of a fixed size. Meaning the size of the pagination is fixed, however based on the content the number of pages may vary. Further more it should not be defined how much is displayed on a single page.
The idea is to use text as input and push as much as can be displayed on the page. Factors that have an influence here is font and formatting.
To determine the page that should be shown I have to figure out the amount of text that can be displayed. To do so I need to know the size of the component containing the text (think Label). The size of the label however is only determined after it is layouted. So here is what I could do:
    @Override
    public void start(Stage primaryStage) {
        Label lbl = new Label("uitroweigudfgf jkfhgklfsjghslkghs kflgskjgh");
        System.out.println(lbl.getWidth()+","+lbl.getHeight());
        lbl.widthProperty().addListener(new ChangeListener<Number>(){
            @Override
            public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
                System.out.println(lbl.getWidth()+","+lbl.getHeight());
        lbl.heightProperty().addListener(new ChangeListener<Number>(){
            @Override
            public void changed(ObservableValue<? extends Number> ov, Number t, Number t1) {
                System.out.println(lbl.getWidth()+","+lbl.getHeight());
        StackPane root = new StackPane();
        root.getChildren().add(lbl);
        Scene scene = new Scene(root, 300, 250);
        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
After the third change I have the dimensions of the label. With this method I would have to push the whole text into labels to figure out how much can be displayed.
Is there any better method to do this?

Answer 1

Have not tried that yet, but will hopefully come around to it. I tried to us a size change listener on the label using this base implementation of a ChangeListener:
package javafxtest.label;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
public class SizeChangeListener implements ChangeListener<Number>{
    private volatile int sizeChangeCounter = 0;
    @Override
    public final void changed(ObservableValue<? extends Number> observable, Number oldValue, Number newValue) {
System.out.println("New value: "+newValue+", counter="+sizeChangeCounter);
        if (sizeChangeCounter < 1) { // one change for height one for width
System.out.println("Increase counter");
            sizeChangeCounter++;
        } else {
            sizeChangeCounter++;
            executeOnSizeChange();
    protected void executeOnSizeChange() {
        while (!stopCriteriumReached()) {
            System.out.println("Execute on after a sizeChange");
    private boolean flag = true;
    protected boolean stopCriteriumReached() {
        flag = !flag;
        return flag;
And here is the application for testing:
package javafxtest.label;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class LabelGrowingSizeChangeTest extends Application {
    @Override
    public void start(Stage primaryStage) {
        Label lbl = new Label(" ");
        MySizeChangeListener changeListener = new MySizeChangeListener(lbl, 250);
        lbl.widthProperty().addListener(changeListener);
        lbl.heightProperty().addListener(changeListener);
        StackPane root = new StackPane();
        root.getChildren().add(lbl);
        Scene scene = new Scene(root, 300, 250);
        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    public static void main(String[] args) {
        launch(args);
    private static class MySizeChangeListener extends SizeChangeListener {
        private final Label label;
        private final double width;
        public MySizeChangeListener(Label label, double width) {
            this.label = label;
            this.width = width;
        @Override
        protected void executeOnSizeChange() {
            while (!stopCriteriumReached()) {
System.out.println("Add text");
                label.textProperty().concat(" blah");
                //label.setText(label.getText()+" blah");
The curious thing is that I get the println from line 48, but the label does not get updated. Has anyone an idea why that is?