FXMLLoader getController returns NULL?

Question

I have the main application class that does the following just fine:

   @Override
   public void start(Stage primaryStage) {
      try {
         FXMLLoader loader = new FXMLLoader(getClass().getResource(
               "RecordScreen.fxml"));
         Parent root = (Parent) loader.load();
         Scene newScene = new Scene(root);
         Stage newStage = new Stage();
         newStage.setScene(newScene);
         newStage.show();
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

It launches a table view that displays people. I select a person, hit the edit button, and try to launch a window that will let me edit them.

   @FXML
   public void editPerson() {
      try {
         FXMLLoader loader = new FXMLLoader(getClass().getResource(
               "PersonEditor.fxml"));
         PersonEditorCtrl ctrl = loader.getController();
         ctrl.init(table.getSelectionModel().getSelectedItem());
         Parent root = (Parent) loader.load();
         Scene newScene = new Scene(root);
         Stage newStage = new Stage();
         newStage.setScene(newScene);
         newStage.show();
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

The problem is, getController is returning null. I have been following this pattern for the past 2 weeks with no problems whatsoever. What am I doing wrong now? These untraceable bugs are aggravating!!!

Here are my two fxmls:

The screen with tableview:

<AnchorPane xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="application.RecordsCtrl">
  <!-- TODO Add Nodes -->
  <children>
    <VBox id="VBox" alignment="CENTER" spacing="0.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
      <children>
        <TableView fx:id="table" prefHeight="-1.0" prefWidth="-1.0">
          <columns>
            <TableColumn prefWidth="75.0" text="Name" fx:id="nameCol" />
            <TableColumn prefWidth="75.0" text="Age" fx:id="ageCol" />
          </columns>
        </TableView>
        <Button mnemonicParsing="false" onAction="#editPerson" text="Edit" />
      </children>
    </VBox>
  </children>
</AnchorPane>

The person editor:

<AnchorPane xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="application.PersonEditorCtrl">
  <!-- TODO Add Nodes -->
  <children>
    <VBox layoutX="0.0" layoutY="0.0" prefHeight="-1.0" prefWidth="-1.0">
      <children>
        <TextField fx:id="nameField" prefWidth="200.0" />
        <TextField fx:id="ageField" prefWidth="200.0" />
        <Button mnemonicParsing="false" text="Button" />
      </children>
    </VBox>
  </children>
</AnchorPane>

score 68 · Accepted Answer · answered May 04 '14 at 20:34

Change this

@FXML
   public void editPerson() {
      try {
         FXMLLoader loader = new FXMLLoader(getClass().getResource(
               "PersonEditor.fxml"));
         PersonEditorCtrl ctrl = loader.getController();
         ctrl.init(table.getSelectionModel().getSelectedItem());
         Parent root = (Parent) loader.load();
         Scene newScene = new Scene(root);
         Stage newStage = new Stage();
         newStage.setScene(newScene);
         newStage.show();
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

To that:

@FXML
   public void editPerson() {
      try {
         FXMLLoader loader = new FXMLLoader(getClass().getResource(
               "PersonEditor.fxml"));
         Parent root = (Parent) loader.load();
         PersonEditorCtrl ctrl = loader.getController();
         ctrl.init(table.getSelectionModel().getSelectedItem());

         Scene newScene = new Scene(root);
         Stage newStage = new Stage();
         newStage.setScene(newScene);
         newStage.show();
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

You first have to run loader.load() then you can get the Controller.

Patrick

For sure. By the way, can you point me in the right direction? My tableview does not reflect the changes made to the people on the list. When I edit them again with the edit button, the changes are there. It's just that the TableView doesn't reflect them. — Toni_Entranced, May 04 '14 at 20:57
Actually never mind, I think I've figure it out. The observable list is causing issues for a lot of people. :\ — Toni_Entranced, May 04 '14 at 21:04
@Luc The difference is, that the op has to call the load() method on his FXMLoader first, then he can call getController() Method. — Patrick, Jan 29 '15 at 08:20

score 2 · Answer 2 · answered Feb 27 '23 at 12:37

2

In your scene builder, you need to make sure that you have explicitly stated the fx:controller attribute.

To do this:

Open your desired FXML file in Scenebuilder.
Click on the controller drop down.
Select the controller class.

If you do not specify the fx:controller it will return null.

answered Feb 27 '23 at 12:37

lionel muskwe

21
2

while a missing controller attribute _could_ be a problem, in this question it's _not_ the case :) - both fxml files shown in the question have the fx:controller set. See the accepted answer for the cause of the null. – kleopatra Feb 27 '23 at 13:38

FXMLLoader getController returns NULL?

2 Answers2

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