JavaFX: FXML: How to make the child to extend its size to fit the parent pane?

Question

I have managed to load a child fxml(sub UI) under a parent fxml (mainMenu UI). I have created an AnchorPane with id \"mainContent\". This pane is bound to 4 sides and change

Answer 1

You could try with setting prefWidth. I don't know why, but it seems like it takes the prefWidth which is set in SceneBuilder after referencing your newPane to your AnchorPane.

Node newPane = FXMLLoader.load(getClass().getResource("view/YourPane.fxml"));
List parentChildren = ((Pane)yourAnchorPaneId.getParent()).getChildren();
parentChildren.set(parentChildren.indexOf(yourAnchorPaneId), newPane);
yourAnchorPaneId.setPrefWidth(1800); // 1800 just example value for test
Main.primaryStage.setWidth(500); // 500 example value with which you wishe to start app