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JavaFX Progress Indicator not updating properly

I am creating a JavaFX desktop app on which I am simulating some work load. I want the app to have a progress indicator that updates dynamically (with time passing at the moment) to show how the load process is progressing. This is my application class:
public class App extends Application {
#Override
public void init() throws InterruptedException{
//Simulation of time consuming code.
for(int i = 0; i<=10; i++) {
notifyPreloader(new Preloader.ProgressNotification(i/10));
System.out.println("Progress is being set by the app to: " + (i/10));
Thread.sleep(500);
}
}
#Override
public void start(Stage primaryStage) {
Parent root;
try {
root = FXMLLoader.load(getClass().getResource("/gui/fxml/App.fxml"));
Scene scene = new Scene(root, 600, 400);
scene.getStylesheets().add("/gui/style/app.css");
primaryStage.setScene(scene);
primaryStage.setTitle("Hello World!");
primaryStage.show();
} catch (IOException e) {
e.printStackTrace();
}
}
}
This is my preloader class:
public class AppPreloader extends Preloader {
private Stage preloaderStage;
private Parent root;
private Scene scene;
private ProgressIndicator progress_indicator;
#Override
public void start(Stage primaryStage) throws Exception {
this.preloaderStage = primaryStage;
this.preloaderStage.setScene(this.scene);
this.preloaderStage.show();
this.progress_indicator = (ProgressIndicator) scene.lookup("#progressIndicator");
}
#Override
public void init() throws Exception {
root = FXMLLoader.load(getClass().getResource("/gui/fxml/AppPreloader.fxml"));
Platform.runLater(new Runnable() {
#Override
public void run() {
scene = new Scene(root, 600, 400);
scene.getStylesheets().add("/gui/style/appPreloader.css");
}
});
}
#Override
public void handleProgressNotification(ProgressNotification pn) {
if(pn instanceof ProgressNotification){
progress_indicator.setProgress(pn.getProgress());
System.out.println("Progress is being set by the handle method to: " + pn.getProgress());
}
}
#Override
public void handleStateChangeNotification(StateChangeNotification evt) {
if (evt.getType() == StateChangeNotification.Type.BEFORE_START) {
preloaderStage.hide();
}
}
}
Whit the print sentences I've been able to identify two problems: First, the
handleProgressNotification method is being called twice, once to be set to 0 and other to be set to 1, before the loop of the init method of the App class starts. Who is making the call? How can I avoid it?
The second problem is that the print sentence inside the init method of the app class is always printing 0.0. How can that be possible? Is it a matter of concurrency?
In addition I need to say that I've checked both of this questions (progressbar in preloader does not update and javafx preloader not updating progress) and didn't find a solution for my problem.
Thanks a lot for your time.

First, you're not seeing the progress values you expect because you are using integer arithmetic: i and 10 are both integers, so i/10 is 0 for 0 <= i < 10 and 1 when i=10.
Second, the handleProgressNotification and handleStateChangeNotification methods are part of the lifecycle of the application that are related to loading the resources. These are really leftovers from the days when JavaFX still supported web deployments and are probably of limited use now.
To receive notifications from the application, you need to override the handleApplicationNotification(...) method instead. Here is a corrected version of the two classes (also modified to be stand-alone so they can be copied and run: please provide these kinds of examples in your questions) that works:
package application;
import javafx.application.Application;
import javafx.application.Preloader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class App extends Application {
#Override
public void init() throws InterruptedException{
//Simulation of time consuming code.
for(int i = 0; i<=10; i++) {
notifyPreloader(new Preloader.ProgressNotification(i/10.0));
System.out.println("Progress is being set by the app to: " + (i/10.0));
Thread.sleep(500);
}
notifyPreloader(new Preloader.StateChangeNotification(Preloader.StateChangeNotification.Type.BEFORE_START));
}
#Override
public void start(Stage primaryStage) {
Parent root;
root = new StackPane(new Label("Hello World"));
Scene scene = new Scene(root, 600, 400);
primaryStage.setScene(scene);
primaryStage.setTitle("Hello World!");
primaryStage.show();
}
}
package application;
import javafx.application.Preloader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.ProgressIndicator;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class AppPreloader extends Preloader {
private Stage preloaderStage;
private Parent root;
private Scene scene;
private ProgressIndicator progress_indicator;
#Override
public void start(Stage primaryStage) throws Exception {
progress_indicator = new ProgressIndicator();
root = new StackPane(progress_indicator);
scene = new Scene(root, 600, 400);
this.preloaderStage = primaryStage;
this.preloaderStage.setScene(this.scene);
this.preloaderStage.show();
}
#Override
public void handleApplicationNotification(PreloaderNotification pn) {
if (pn instanceof ProgressNotification) {
//expect application to send us progress notifications
//with progress ranging from 0 to 1.0
double v = ((ProgressNotification) pn).getProgress();
progress_indicator.setProgress(v);
} else if (pn instanceof StateChangeNotification) {
StateChangeNotification scn = (StateChangeNotification) pn ;
if (scn.getType() == StateChangeNotification.Type.BEFORE_START) {
preloaderStage.hide();
}
}
}
}

JavaFX animation restore to original state

My goal here is to have some animation on a node (such as a fade transition) that serves as a temporary notice that something is happening. I want the animation completely gone, like it never happened when that something has ended.
The code snipped below is an example of the problem I'm having. In the current state, when the button is hit to stop the process the button just stays at it's current opacity. If the commented line is uncommented, the button no longer stays at it's current opacity but updates to look correct. My problem then is that when the button is hit again, the CSS opacity for the default stylesheet (Modena.css for JavaFX 8) is no longer taking effect.
Is there something I'm doing wrong, or is there a better way altogether?
package gui.control.custom;
import javafx.animation.Animation;
import javafx.animation.FadeTransition;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
import javafx.util.Duration;
public class Test extends Application {
#Override
public void start(Stage primaryStage) throws Exception {
Stage stage = new Stage();
HBox box = new HBox();
streamButton = new Button("Start");
streamButton.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
if (started) {
stopProcess();
} else {
startProcess();
}
}
});
box.getChildren().add(streamButton);
stage.setScene(new Scene(box));
stage.show();
}
FadeTransition ft;
Button streamButton;
boolean started = false;
private void startProcess() {
streamButton.setDisable(true);
new Thread() {
#Override
public void run() {
try {
Thread.sleep(3000);
} catch (InterruptedException ex) {
}
Platform.runLater(() -> {
started = true;
streamButton.setText("Stop");
streamButton.setDisable(false);
startButtonAnim();
});
}
}.start();
}
private void stopProcess() {
streamButton.setText("Start");
stopButtonAnim();
started = false;
}
private void startButtonAnim() {
ft = new FadeTransition(Duration.millis(500), streamButton);
ft.setFromValue(1.0);
ft.setToValue(0.3);
ft.setCycleCount(Animation.INDEFINITE);
ft.setAutoReverse(true);
ft.play();
}
private void stopButtonAnim() {
ft.stop();
//streamButton.setOpacity(1);
}
public static void main(String[] args) {
launch();
}
}

I think the best solution is to use jumpTo(Duration duration) right before you stop the Animation. Setting the duration to Duration.ZERO.
Circle circle2 = new Circle(250, 120, 80);
circle2.setFill(Color.RED);
circle2.setStroke(Color.BLACK);
FadeTransition fade = new FadeTransition();
fade.setDuration(Duration.millis(5000));
fade.setFromValue(10);
fade.setToValue(0.1);
fade.setCycleCount(1000);
fade.setAutoReverse(true);
fade.setNode(circle2);
fade.play();
Button btnStop = new Button("Stop");
btnStop.setOnAction((event) -> {
fade.jumpTo(Duration.ZERO);
fade.stop();
});

Another idea:
I have found this method in javadoc: getCurrentRate(),
which should give you negative result on reversing, so the code would look like this:
private void stopButtonAnim() {
while(ft.getCurrentRate>=0); //waiting till animation goes (skips if already reversing)
while(ft.getCurrentRate<=0); //and till reverse
ft.stop(); //then stop
streamButton.setOpacity(1); //make it 100% ;)
}
Maybe you have to add Thread.sleep(int) to while cycle

I would try this insetad of simply stop(); this line
setOnFinished(e->tryToStop());
And create this method as:
public void tryToStop(){
if(!started)
fm.stop();
}
stopProcess() method changes the started variable, so it will stop in this two cases:
if it is finished
AND
if it is reqested to stop
Not tested, just an idea

Javafx live thread updates

I'm working with Javafx and threads simultaneously and I constanly run into this problem where I make a button and then when the button is clicked (using event handlers) I make a for loop that changes the button to 1,2,3,4,5 and then delays for a second in the middle of each. Like a count down!
But what happens is it delays for 5 seconds and changes the text of button to 5.
The problem is I want to see it change between 1 and 5 but all I see is 5 at the end of a 5 second delay. I would assume that it changing the button text but I don't see it. I might have to to do with the .show() method in the Javafx class.
public class HewoWorld extends Application implements EventHandler<ActionEvent>
{
Thread t = new Thread();
Button butt;
boolean buttWasClicked = false;
Circle circ1 = new Circle(40, 40, 30, Color.RED);
Circle circ2 = new Circle(100, 100, 30, Color.BLUE);
Group root;
Scene scene;
Stage disStage = new Stage();
int i = 1;
public static void main(String[] args)
{
launch(args);
}
public void start(Stage stage) throws Exception
{
disStage.setTitle("tests stuffs");
Screen screen = Screen.getPrimary();
Rectangle2D bounds = screen.getVisualBounds();
double windh = bounds.getHeight()/2+150;//sets height of screen
double windw = bounds.getWidth()/3;//sets width of screen
Pane layout = new Pane();
butt = new Button();
butt.setText("Hello world");
root = new Group(circ1, circ2, butt);
scene = new Scene(root, 800, 400);
disStage.setWidth(windw);
disStage.setHeight(windh);
butt.setLayoutX(200);
butt.setLayoutY(200);
butt.setOnAction(this);
disStage.setScene(scene);
disStage.show();
}
public void handle(ActionEvent event)
{
if (event.getSource() == butt && buttWasClicked == false)
{
try
{
butt.setText(i+"");
t.sleep(1000);
i++;
}
catch(Exception q)
{
}
circ1 = new Circle(40, 40, 30, Color.BLACK);
circ2 = new Circle(100, 100, 30, Color.RED);
}
}
}

Why your code doesn't work
The reason your code doesn't work is that you are blocking the FX Application Thread.
Like (almost?) all UI toolkits, JavaFX is a single-threaded UI toolkit. This means that all event handlers, and all the rendering of the UI, are performed on a single thread (called the FX Application Thread).
In your code, you have an event handler that takes more than a second to run, because it pauses for a second via a call to Thread.sleep(...). While that event handler is running, the UI cannot be redrawn (because a single thread cannot do two things at once). So while the value of the button's text has changed immediately, the new value won't actually be rendered on the screen until the handle(...) method has finished running. If you had a for loop in the handle method, nothing would be rendered until the entire loop (and anything else in the method) had completed.
How to fix it
The simplest way to do what you want in JavaFX is to use a Timeline to handle the pause. The Timeline manages the threading appropriately for you:
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.util.Duration;
public class CountingButton extends Application {
#Override
public void start(Stage primaryStage) {
Button button = new Button("Count");
Timeline timeline = new Timeline();
for (int count = 0; count <= 5 ; count++) {
final String text = Integer.toString(count);
KeyFrame frame = new KeyFrame(Duration.seconds(count), event ->
button.setText(text));
timeline.getKeyFrames().add(frame);
}
button.setOnAction(e -> timeline.play());
primaryStage.setScene(new Scene(new StackPane(button), 120, 75));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
In general, for changing the appearance of the user interface at specific time points, the JavaFX Animation API (see also the tutorial) can be useful, especially Timeline and PauseTransition.
A "lower-level" way to do this would be to create a Thread yourself and pause in that thread. This is much more advanced: you need to be careful to update the UI on the FX Application Thread, not on the thread you created. You can do this with a call to Platform.runLater(...):
import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class CountingButton extends Application {
#Override
public void start(Stage primaryStage) {
Button button = new Button("Start");
button.setOnAction(e -> {
Thread thread = new Thread(() -> {
for (int i = 0; i <= 5 ; i++) {
final String text = "Count: "+i ;
Platform.runLater(() -> button.setText(text));
try {
Thread.sleep(1000);
} catch (InterruptedException exc) {
exc.printStackTrace();
}
}
});
thread.start();
});
primaryStage.setScene(new Scene(new StackPane(button), 120, 75));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
For more general information on threading in JavaFX, have a look at this post: Using threads to make database requests

What you have to do is to replace the thread use by the following method :
scheduler = Executors.newScheduledThreadPool(1);
scheduler.scheduleAtFixedRate(
new Runnable(){
#Override
public void run() {
Platform.runLater(new Runnable() {
#Override
public void run() {
//Here your code to change the number by for example incrementig the value of the button
}
});
}
},
1000,
80,
TimeUnit.MILLISECONDS);
+1 if it helps :D

In this case you need a timer to run every second and increment a counter on every hit. To my knowledge, the best way to make a timer in javafx is to use a timeline. https://stackoverflow.com/a/9966213/4683264.
int i = 0;// class field
// ....
Timeline fiveSecondsWonder = new Timeline(new KeyFrame(Duration.seconds(1), event ->
button.setText(++i)));
fiveSecondsWonder.setCycleCount(5);// repeat five times
fiveSecondsWonder.play();

How to achieved collision detection in Translate Transition (in JavaFX)?

I have written the below JavaFX program in which two rectangle nodes are in translate transition:
public class Test extends Application{
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
BorderPane borderPane = new BorderPane();
borderPane.setStyle("-fx-background-color: green;");
Rectangle rect1 = new Rectangle(20,20,50, 50);
rect1.setArcHeight(15);
rect1.setArcWidth(15);
rect1.setFill(Color.RED);
Rectangle rect2 = new Rectangle(20,20,30, 30);
rect2.setArcHeight(15);
rect2.setArcWidth(15);
rect2.setFill(Color.RED);
TranslateTransition translateTransition1 = new TranslateTransition(Duration.millis(2000), rect1);
translateTransition1.setFromX(0);
translateTransition1.setToX(300);
translateTransition1.setToY(300);
translateTransition1.setCycleCount(Timeline.INDEFINITE);
translateTransition1.setAutoReverse(true);
translateTransition1.play();
TranslateTransition translateTransition2 = new TranslateTransition(Duration.millis(2000), rect2);
translateTransition2.setFromX(300);
translateTransition2.setToX(0);
translateTransition2.setToY(300);
translateTransition2.setCycleCount(Timeline.INDEFINITE);
translateTransition2.setAutoReverse(true);
translateTransition2.play();
borderPane.getChildren().add(rect1);
borderPane.getChildren().add(rect2);
primaryStage.setScene(new Scene(borderPane, 500, 500));
primaryStage.show();
}
}
How can I implement collision detection of the two rectangle nodes which are in Translate Transition?

With rectangles it's pretty easy; just get their bounds in the parent and see if they intersect. The only drawback with this is it doesn't take into account the curved corners: you may need to compute that by hand if you want that level of accuracy. For non-rectangular shapes you can also just observe the bounds in parent properties, but you'd need to do the computation by hand to see if the shapes intersect.
ObservableBooleanValue colliding = Bindings.createBooleanBinding(new Callable<Boolean>() {
#Override
public Boolean call() throws Exception {
return rect1.getBoundsInParent().intersects(rect2.getBoundsInParent());
}
}, rect1.boundsInParentProperty(), rect2.boundsInParentProperty());
colliding.addListener(new ChangeListener<Boolean>() {
#Override
public void changed(ObservableValue<? extends Boolean> obs,
Boolean oldValue, Boolean newValue) {
if (newValue) {
System.out.println("Colliding");
} else {
System.out.println("Not colliding");
}
}
});

TranslateTransition isn't meant to support Collision Detection. It simply moves A to B without any regards to the state of anything but its node.
You would need a Transition mechanism that is aware of the other objects on the board.
The good news is that creating a Transition isn't too hard. You can create a class that inherits Transition and simply implement the interpolate() method.
From the JavaDoc:
Below is a simple example. It creates a small animation that updates
the text property of a Text node. It starts with an empty String and
adds gradually letter by letter until the full String was set when the
animation finishes.
final String content = "Lorem ipsum";
final Text text = new Text(10, 20, "");
final Animation animation = new Transition() {
{
setCycleDuration(Duration.millis(2000));
}
protected void interpolate(double frac) {
final int length = content.length();
final int n = Math.round(length * (float) frac);
text.setText(content.substring(0, n));
}
};
The bad news is that having a successful collision detection mechanism is a bit harder. I'm really no expert on the subject, but I would probably have a ObservableList of Nodes that have collision, pass it to the Transition and on the interpolate method I would do a intersection check of the node that's moving against all the other nodes and leave it still if he cannot move.
If you want anything better than that, you'll probably want to look into a 2D Game Framework like Slick2D.

EDIT: Made a few simple alterations and went with a State based approach, code has been updated.
Well my approach is different that all the above ...
NOTE: I'm using 1.8 source
I created a Collidable interface:
import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.scene.shape.Shape;
public interface Collidable{
public enum CollisionState{
WAITING,
TOUCHING;
}
ObjectProperty<CollisionState> state = new SimpleObjectProperty<>(CollisionState.WAITING);
public default ReadOnlyObjectProperty<CollisionState> collisionStateProperty(){return state;}
public default CollisionState getCollisionState(){return state.get();}
BooleanProperty collided = new SimpleBooleanProperty(false){{
addListener((ObservableValue<? extends Boolean> observable1, Boolean oldValue, Boolean touching) -> {
if(touching){
state.set(CollisionState.TOUCHING);
}else{
state.set(CollisionState.WAITING);
}
});
}};
public default boolean hasCollided(){return collided.get();}
public default BooleanProperty collidedProperty(){return collided;}
public default void checkCollision(Shape src, Shape other){
if(Shape.intersect(src, other).getBoundsInLocal().getWidth() > -1 && !getCollisionState().equals(CollisionState.TOUCHING)){
collided.set(true);
handleCollision(other);
}else if(Shape.intersect(src, other).getBoundsInLocal().getWidth() <= 0){
collided.set(false);
}
}
public void handleCollision(Shape other);
}
And a simple implementation:
import javafx.animation.Animation;
import javafx.animation.ParallelTransition;
import javafx.animation.TranslateTransition;
import javafx.application.Application;
import javafx.beans.Observable;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.scene.paint.Paint;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.Shape;
import javafx.stage.Stage;
import javafx.util.Duration;
/**
*
* #author Dub-Laptop
*/
public class CollisionTesting extends Application {
private TranslateTransition cAnim;
#Override
public void start(Stage primaryStage) {
Group root = new Group();
Scene scene = new Scene(root);
primaryStage.setTitle("Collision Testing");
primaryStage.setScene(scene);
primaryStage.show();
Rectangle r = new Rectangle(100,50, Color.AQUA);
r.setLayoutX(10);
r.setLayoutY(200);
CollidableCircle c = new CollidableCircle(50, Color.GREEN);
c.setLayoutX(800);
c.setLayoutY(200);
/* can change this to anything you like
I used translateXProperty for simplicity
*/
c.translateXProperty().addListener((Observable observable) -> {
c.checkCollision(c, r);
});
root.getChildren().addAll(r, c);
TranslateTransition rAnim = new TranslateTransition();
rAnim.setToX(600);
rAnim.setAutoReverse(true);
rAnim.setCycleCount(Animation.INDEFINITE);
rAnim.setDuration(Duration.seconds(5));
rAnim.setNode(r);
cAnim = new TranslateTransition();
cAnim.setToX(-590);
cAnim.setAutoReverse(true);
cAnim.setCycleCount(Animation.INDEFINITE);
cAnim.setDuration(Duration.seconds(5));
cAnim.setNode(c);
rAnim.play();
cAnim.play();
}
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
private class CollidableCircle extends Circle implements Collidable{
public CollidableCircle(double radius, Paint fill) {
super(radius, fill);
new AnimationTimer(){
#Override
public void handle(long now) {
root.getChildren().filtered((Node n)->{
return !n.equals(CollidableCircle.this) && n instanceof Shape;
}).forEach(other ->{
checkCollision(CollidableCircle.this, (Shape)other);
});
}
}.start();
// I added this for local property changes to this node
collisionStateProperty().addListener((ObservableValue<? extends CollisionState> observable, CollisionState oldValue, CollisionState newValue) -> {
if(newValue.equals(CollisionState.TOUCHING)){
setScaleX(1.25);
setScaleY(1.25);
setFill(Color.GREENYELLOW);
cAnim.pause();
}else if(newValue.equals(CollisionState.WAITING)){
setScaleX(1.0);
setScaleY(1.0);
setFill(Color.GREEN);
cAnim.play();
}
});
}
#Override
public void handleCollision(Shape other) {
// handle updates that affect other node here
System.out.println("Collided with : " + other.getClass().getSimpleName());
}
}
}
IMHO rather than using Bounds for checking Shape collisions, use the boolean :
(Shape.intersect(s1,s2).getBoundsInLocal().getWidth() > -1)
This approach is more accurate for Shapes as it will check for non-null pixels within the Shape Bounds, rather than the normal rectangular Bounds.
Though if you really want to use Bounds, this should work also:
if(sourceShape.getBoundsInLocal().intersects(otherShape.getBoundsInParent()){
Shape intersect = Shape.intersect(sourceShape, otherShape);
if(intersect.getBoundsInLocal().getWidth > -1){
// handle code here
}
}
though, as you can see it's more verbose and virtually the same as my other method.
Hope this helps.

dragging nodes when their parent has a transformation results in nodes disappearing

Very weird problem, I finally managed to distill it into a small piece of code which demonstrates the problem. I have a pane, which contains 1 group, that groups contains a group which contains some ellipses. The top group has a rotate transform applied to it. The ellipses are made draggable.
Try the below example, drag some ellipses downwards (outside the group's bounds), you'll see them disappearing. If you maximize the window, they appear again but you can't drag them anymore, they don't receive any events anymore.
Now for the really strange part, there are three ways I can make the problem go away:
don't apply the transform
remove one ellipse (!?) (I experimented to get to this number, 11)
start ScenicView alongside and select the group containing the ellipses so you can see the bounds of the group
I'm at a total loss here, completely stupefied. Please, does anyone have any idea why this problem is occuring and how to solve it?
Code (JavaFX 2.2.3 and java 1.7.0_09 64bit Windows 7):
import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.geometry.Point2D;
import javafx.scene.Group;
import javafx.scene.GroupBuilder;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.SceneBuilder;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Ellipse;
import javafx.scene.shape.EllipseBuilder;
import javafx.scene.transform.Rotate;
import javafx.scene.transform.RotateBuilder;
import javafx.stage.Stage;
public class DragProblem extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
DrawingPane drawingPane = new DrawingPane();
drawingPane.setStyle("-fx-background-color: darkgrey;");
Scene scene = SceneBuilder.create().root(drawingPane).width(1280d).height(1024d).build();
primaryStage.setScene(scene);
primaryStage.show();
}
public class DrawingPane extends Pane {
private Group transformedGroup;
private Group splinePoints;
public DrawingPane() {
transformedGroup = GroupBuilder.create().id("transformedGroup").build();
getChildren().add(transformedGroup);
addPoints();
makePointsDraggable();
}
public void addPoints() {
double[] coords = new double[] {
// comment any one the below x,y coordinates and the problem doesn't occur..
239.28353881835938, 488.2192687988281,
245.04466247558594, 505.30169677734375,
258.56671142578125, 539.49462890625,
267.2294006347656, 563.618408203125,
282.89141845703125, 587.84033203125,
309.6925048828125, 602.2174072265625,
327.4945068359375, 616.4683227539062,
345.25445556640625, 633.718994140625,
371.0416259765625, 649.0819702148438,
393.78704833984375, 667.402587890625,
442.67010498046875, 676.0886840820312 };
splinePoints = GroupBuilder.create().build();
for (int i = 0; i < coords.length; i += 2) {
Ellipse ellipse = EllipseBuilder.create().radiusX(3).radiusY(3).centerX(coords[i]).centerY(coords[i + 1]).build();
splinePoints.getChildren().add(ellipse);
}
transformedGroup.getChildren().add(splinePoints);
Rotate rotateTransform = RotateBuilder.create().build();
rotateTransform.setPivotX(224);
rotateTransform.setPivotY(437);
rotateTransform.setAngle(15);
// ..or comment this line to prevent the problem occuring
transformedGroup.getTransforms().add(rotateTransform);
}
public void makePointsDraggable() {
for (final Node n : splinePoints.getChildren()) {
Ellipse e = (Ellipse) n;
final NodeDragHandler ellipseDragHandler = new NodeDragHandler(e, transformedGroup);
e.setOnMousePressed(ellipseDragHandler);
e.setOnMouseDragged(ellipseDragHandler);
}
}
}
public class NodeDragHandler implements EventHandler<MouseEvent> {
protected final Ellipse node;
private final Node transformedGroup;
private double initialX;
private double initialY;
private Point2D initial;
private boolean dragStarted = false;
public NodeDragHandler(Ellipse node, Group transformedGroup) {
this.node = node;
this.transformedGroup = transformedGroup;
}
#Override
public void handle(MouseEvent event) {
if (!dragStarted) {
initialX = event.getScreenX();
initialY = event.getScreenY();
initial = transformedGroup.localToParent(new Point2D(node.getCenterX(), node.getCenterY()));
dragStarted = true;
} else {
double xDragged = event.getScreenX() - initialX;
double yDragged = event.getScreenY() - initialY;
Point2D newPos = new Point2D(initial.getX() + xDragged, initial.getY() + yDragged);
Point2D p = transformedGroup.parentToLocal(newPos.getX(), newPos.getY());
node.setCenterX(p.getX());
node.setCenterY(p.getY());
}
}
}
}

It's been acknowledged as a bug in JavaFX and will be solved in 2.2.6, see here. I've tested it with the early access release and I can confirm it has been solved.