How to detect when JavaFx mouse event occurs in the "label" are of a TitledPane?

Question

I have an Accordian with multiple TitledPanes. When a TitledPane is expanded, there are "dead areas" on the pane that do not have sub-components (e.g., buttons, text, etc.).

Right now, when I check MouseEvent.getSource(), it returns an instance of TitledPane for all areas. Is there a way to specifically constrain/check for a mouse-click on the "title" section of the TitledPane?

Answer 1

I don't think there is a public API to detect mouse click on title region, however it is possible to do that this way:

titledPane.setOnMouseClicked(new EventHandler<MouseEvent>() {
    @Override
    public void handle(MouseEvent event) {
        EventTarget target = event.getTarget();
        String clazz = "class com.sun.javafx.scene.control.skin.TitledPaneSkin$TitleRegion";
        if(target.getClass().toString().equals(clazz) || // anywhere on title region except title Text
            (target instanceof Node && ((Node) target).getParent().getClass().toString().equals(clazz))) // title Text
            System.out.println("title was clicked");
    }
});

But this method is highly discouraged as it relies on some internal implementation detail that may be subject to change.

May be it's better to think more about what you actually need. Maybe your actual requirement can be fulfilled by uisng TitledPane's public API methods and properties.

For insatnce expandedProperty()'s value gets changed every time mouse click occurs on title region (if isCollapsible() is set to true).

titledPane.expandedProperty().addListener(new ChangeListener<Boolean>() {
    @Override
    public void changed(ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) {
        System.out.println("mouse click changed expanded from " + oldValue + " to " + newValue);
    }
});