How to play pathtransitions in sequence? - javafx

Question

Is there a special way (some kind of event/transition queue?) in JavaFX with which you can play animations/transitions in sequence?
In a solitaire game at the end the cards are usually already in sequence (K->-Q->J-10->-9->...) and I want to finish them automatically. So first card 9 has to move from the tableau to the foundation, then 10, then J, etc.
I'd like to do the path transition in a transition queue, rather than all at once.
I can't use a SequentialTranstition because you can't modify its children once the animation plays.
public final ObservableList getChildren()
A list of Animations that will be played sequentially.
It is not possible to change the children of a running
SequentialTransition. If the children are changed for a running
SequentialTransition, the animation has to be stopped and started
again to pick up the new value.
Verifiable with this minimal example:
public class PathTransitionDemo extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
Group root = new Group();
List<Rectangle> rectangles = new ArrayList<>();
double w = 50;
double h = 50;
double spacing = 10;
for( int i=0; i < 10; i++) {
Rectangle rectangle = new Rectangle ( spacing * (i+1) + w * i, 50, w, h);
rectangle.setStroke( Color.BLUE);
rectangle.setFill( Color.BLUE.deriveColor(1, 1, 1, 0.2));
rectangles.add( rectangle);
}
root.getChildren().addAll( rectangles);
primaryStage.setScene(new Scene(root, 1024, 768));
primaryStage.show();
// transition
SequentialTransition seq = new SequentialTransition();
for( Rectangle rectangle: rectangles) {
Path path = new Path();
path.getElements().add (new MoveTo ( rectangle.getX(), rectangle.getY()));
path.getElements().add (new LineTo( 900, 600));
PathTransition pathTransition = new PathTransition();
pathTransition.setDuration(Duration.millis(1000));
pathTransition.setNode(rectangle);
pathTransition.setPath(path);
//pathTransition.play();
seq.getChildren().add( pathTransition);
if( seq.getStatus() != Status.RUNNING)
seq.play();
}
// seq.play();
}
}
The sequential transition stops after it played the first path transition.
A solution would be to modfiy the setOnFinished handler of the PathTransitions. But that's ugly. And it plays only exaclty 1 transtition after the other. Let's say one card transition lasts 2000 ms, it e. g. limits the possibility to start another transition of the queue within 500ms.
The animation in the Video Wall that I created has a similar requirement. There I solved it with an AnimationTimer. Excerpt from the code:
AnimationTimer timer = new AnimationTimer() {
long last = 0;
#Override
public void handle(long now) {
if( (now - last) > 40_000_000)
{
if( transitionList.size() > 0) {
ParallelTransition t = transitionList.remove(0);
t.getNode().setVisible(true);
t.play();
}
last = now;
}
if( transitionList.size() == 0) {
stop();
}
}
};
Is there a better way to solve this in JavaFX?
Thank you very much!