Javafx - how to modify components in fxml file after loading it - javafx

Question

I am a novice to javafx. I created a simple javafx fxml application. I defined a treeView in my fxml file. It is as follows,
FXMLDocument.fxml
<AnchorPane id="AnchorPane" prefHeight="200.0" prefWidth="320.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="scenebuilderfirst.FXMLDocumentController">
<children>
<TreeView id="" fx:id="tree" layoutX="60.0" layoutY="14.0" prefHeight="172.0" prefWidth="200.0" />
</children>
</AnchorPane>
and created the controller class as follows,
FXMLDocumentController.java
public class FXMLDocumentController implements Initializable {
#FXML
private TreeView<?> tree;
#Override
public void initialize(URL url, ResourceBundle rb) {
}
}
my main java file is as follows,
MyApp.java
public class SceneBuilderFirst extends Application {
#Override
public void start(Stage stage) throws Exception {
AnchorPane root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
Now I need to add tree items to the TreeView while running the program. So I thought of writing the following peace of code inside the initialize() method of my contorller class,
// creating root item for the tree
TreeItem<String> rootItem = new TreeItem<>("root");
rootItem.setExpanded(true);
//creating childern for the tree
TreeItem<String>item1= new TreeItem<>("content1");
rootItem.getChildren().add(item1);
TreeItem<String>item2= new TreeItem<>("content2");
rootItem.getChildren().add(item2);
//attaching root item to tree
tree = new TreeView<>(rootItem);
But it didn't work.
I need to set the TreeItems while running the program. Not through the fxml file.
So I think I should do the coding in my main java file
I need a way to access my TreeView after loading it via FXMLLoader in my main java file so i can make a TreeView on my own choice and attach it to this TreeView while running the program. Please guide me.

Answer 1

To fix this, replace
tree = new TreeView<>(rootItem);
with
tree.setRoot(rootItem);
For an explanation of why, see this discussion.
You also have to fix your declaration of the TreeView:
#FXML
private TreeView<String> tree;