How to get data from multiple Nested FXMLs And call methods on their controllers

Question

Here's what my project looks like:

Main.FXML

• AnchorPane
  • VBox [Egg Container] id="_eggContainer"
  • Button [Add Egg] --> Adds an eggview to _eggContainer
  • Button [Print Eggs] --> prints all eggs' properites
  • Button [Break Eggs] --> Calls break method on each egg

EggView.FXML

• HBox
  • Label: [Egg ID] Should be incremented each time an eggView is instantiated
  • TextField: [Egg Color]

MainController.java

public class MainController implements Initializable {   

    /***CONTROLS***/
    @FXML private VBox   _eggsContainer;
    @FXML private Button _btnAddEgg;
    @FXML private Button _btnPrintEggs;
    @FXML private Button _btnBreakEggs;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        _btnAddEgg.setOnMouseClicked(e -> {
            doAddEgg();
        });
        _btnPrintEggs.setOnMouseClicked(e -> {
            doPrintAllEggs();
        });
        _btnBreakEggs.setOnMouseClicked(e -> {
            doBreakAllEggs();
        });
    }

    // Add an egg to _eggsContainer
    private void doAddEgg() {
        HBox eggControl = null;
        try {
            eggControl = FXMLLoader.load(getClass().getResource("EggView.fxml"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        _eggsContainer.getChildren().add(eggControl);
    }

    private void doPrintAllEggs() {
        // prints ID and Color of each egg in _eggsContainer
    }

    private void doBreakAllEggs() {
        // call the break method in EggController controller on each egg
    }
}

EggController.java

public class EggController {

    /***CONTROLS***/
    @FXML private Label _eggID;
    @FXML private TextField _eggColor;

    public void doBreakEgg() {
        // TODO: Break Egg
    }

    /****************************************************************
     **********                  ACCESSORS               ************
     ****************************************************************/
    public String getEggID() {
        return _eggID.getText();
    }

    public String setEggID(String id) {
        return _eggID.setText(id);
    }

    public String getEggColor() {
        return _eggColor.getText();
    }

}

Now how can i access each eggs data and methods from my main controller? Without having to give each egg an ID and reference it in MainController.

Answer 1

Get the controllers from the FXMLLoaders when you load EggView.fxml, and put them in a list. (As an aside, don't use mouse listeners to handle button actions.)

public class MainController implements Initializable {   

    /***CONTROLS***/
    @FXML private VBox   _eggsContainer;
    @FXML private Button _btnAddEgg;
    @FXML private Button _btnPrintEggs;
    @FXML private Button _btnBreakEggs;

    private final List<EggController> eggs = new ArrayList<>();

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        _btnAddEgg.setOnAction(e -> {
            doAddEgg();
        });
        _btnPrintEggs.setOnAction(e -> {
            doPrintAllEggs();
        });
        _btnBreakEggs.setOnAction(e -> {
            doBreakAllEggs();
        });
    }

    // Add an egg to _eggsContainer
    private void doAddEgg() {
        HBox eggControl = null;
        try {
            FXMLLoader loader = new FXMLLoader(getClass().getResource("EggView.fxml"));
            eggControl = loader.load();
            EggController controller = loader.getController();
            eggs.add(controller);
        } catch (IOException e) {
            e.printStackTrace();
        }
        _eggsContainer.getChildren().add(eggControl);
    }

    private void doPrintAllEggs() {
        // prints ID and Color of each egg in _eggsContainer
        for (EggController controller : eggs) {
            System.out.println(controller.getEggId() + " : " + controller.getEggColor());
        }
    }

    private void doBreakAllEggs() {
        eggs.forEach(EggController::doBreakEgg);
    }
}