FX - the transition of the tree node arrow icon

Question

I want to know how can I realize this following transition effect in the TreeView:
There is a arrow icon for collapse and expand. I want to see that this arrow icon appears when the tree view obtains its focus and disappears when it looses the focus. The appearance time is defined to 1s and the disappearance time is 2s.
Anyone could help me ^^ ? Thanks.

Answer 1

You have to use a Cell factory to accomplish this. Here is a quick and dirty example.
        TreeView<String> treeView = new TreeView<String>();
        treeView.setCellFactory(new Callback<TreeView<String>,TreeCell<String>>() {
            @Override
            public TreeCell<String> call(TreeView<String> p) {
                return new TreeCell<String>() {
                    @Override
                    protected void updateItem(String item, boolean empty) {
                        super.updateItem(item, empty);
                        setText(item);
                        javafx.animation.FadeTransitionBuilder.create()
                            .node(getDisclosureNode())
                            .duration(Duration.seconds(2d))
                            .fromValue(1d).toValue(0d)
                            .build()
                        .play();
        });