Get Controller instance from Node - javafx

Question

There is an possibility to get Controller instance from Node ?? for example AnchorPane on Tab ?
I have some AnchorPanes where I load different Controllers and I would like to verify which controller is already loaded

Answer 1

Nodes do not contain any information about a controller used with the fxml file used to create it by default, since fxml is just one way of creating a scene. However you could attach information like this to the userData/properties in the fxml:
<AnchorPane xmlns:fx="http://javafx.com/fxml/1" fx:id="AnchorPane" prefHeight="400.0" prefWidth="600.0" onMouseClicked="#click" fx:controller="fxml.FXMLController">
<!-- store controller as userData property -->
<userData>
<fx:reference source="controller" />
</userData>
<properties>
<!-- store controller at key "foo" in properties map -->
<foo><fx:reference source="controller" /></foo>
</properties>
</AnchorPane>
If you do this, you can lookup the controller at closest ancestor of a node where you added this kind of information using
public static Object getController(Node node) {
Object controller = null;
do {
controller = node.getProperties().get("foo");
node = node.getParent();
} while (controller == null && node != null);
return controller;
}
to retrieve the info from the properties map or using
public static Object getController(Node node) {
Object controller = null;
do {
controller = node.getUserData();
node = node.getParent();
} while (controller == null && node != null);
return controller;
}
to retrieve the info from the userData property.
You should probably use just one way of adding the info though, not both. Also it would be better to replace foo as key...

Answer 2

It's an old question, but if you have a main window, where you include other fxml files like this:
<AnchorPane prefHeight="900.0" prefWidth="1600.0" xmlns="http://javafx.com/javafx/16" xmlns:fx="http://javafx.com/fxml/1"
fx:controller="MainController">
<!-- <HBox></HBox>, some elements here, your normal usual FXML-->
<fx:include fx:id="someAnchorPane" source="SomeAnchorPane.fxml"/>
</AnchorPane>
and your SomeAnchorPane.fxml has fx:controller property set to SomeOtherController, then you can add a controller field in your MainController like this:
#FXML private SomeOtherController someAnchorPaneController;
And it will inject appropriate controller in this field automatically.
The key thing here is that your field has to be named "fx:id+Controller" for it to work.