Building Dynamic UI Layouts in JavaFX - JavaFX 8: A Definitive Guide to Building Desktop, Mobile, and Embedded Java Clients - page 219

■ even though the starting value of the opacity was set to 0, you still need to set the fromValue property of the
transition to 0 explicitly for it to work correctly in reverse.

Note

The last step is to add in the event listeners that will fire when the user mouses over the Node . These can be added
by calling the addEventHandler method with a lambda expression that accepts MouseEvents :

addEventHandler(MouseEvent.MOUSE_ENTERED_TARGET, t -> {
if (model.legalMove(x, y).get()) {
highlightTransition.setRate(1);
highlightTransition.play();
}
});
addEventHandler(MouseEvent.MOUSE_EXITED_TARGET, t -> {
highlightTransition.setRate(-1);
highlightTransition.play();
});

Notice that the code plays the same animation in either case, but changes the rate of the animation based on
whether it should be played forwards (1) or backwards (-1). This ensures that the animation will seamlessly transition
even if it is in progress.
When run, the Reversi application now animates a subtle blue outline over the highlighted Node under the cursor,
as shown in Figure 5-16 .

Figure 5-16. The Reversi application with a highlight animation over the active cell