Javafx: Reusable collections using FXML

Question

I'd like to bind a single collection to multiple ChoiceBox's in FXML. However the only way I know how is using:

<ChoiceBox fx:id="cb00" prefWidth="150.0" GridPane.rowIndex="0" GridPane.columnIndex="0">
    <items>
        <FXCollections fx:id="test" fx:factory="observableArrayList">
            <String fx:value="1" />
            <String fx:value="2" />
            <String fx:value="3" />
            <String fx:value="4" />
            <String fx:value="5" />
            <String fx:value="6" />
            <String fx:value="7" />
            <String fx:value="8" />
            <String fx:value="9" />
        </FXCollections>
    </items>
</ChoiceBox>

Is it possible to declare the collection in the controller and refer to it in FXML instead of copying the collection for each ChoiceBox?

Answer 1

You can define the items in the controller:

public class Controller {

    private ListProperty<String> choiceBoxItems = new SimpleListProperty(FXCollections.observableArrayList());

    public Controller() {
        IntStream.range(1,10).mapToObj(i -> Integer.toString(i))
            .forEach(choiceBoxItems::add);
    }

    public ListProperty<String> choiceBoxItemsProperty() {
        return choiceBoxItems ;
    }

    public ObservableList<String> getChoiceBoxItems() {
        return choiceBoxItemsProperty().get() ;
    }

    public void setComboBoxItems(ObservableList<String> choiceBoxItems) {
        choiceBoxItemsProperty().set(choiceBoxItems) ;
    }

    // ...
}

and then (this is not tested, but I think it will work):

<ChoiceBox fx:id="cb00" items="${controller.choiceBoxItems}" prefWidth="150.0" GridPane.rowIndex="0" GridPane.columnIndex="0">

See expression binding in the FXML documentation. (It's not actually documented that the controller is available in the FXML namespace with key controller, but I think it is safe to use this.)

You can also just define the list in the FXML using fx:define:

<fx:define>

    <FXCollections fx:id="choiceBoxItems" fx:factory="observableArrayList">
        <String fx:value="1"/>
        <String fx:value="2"/>
        <String fx:value="3"/>
        <!-- ... -->
    </FXCollections>

</fx:define>

and then refer to it in each choice box:

<ChoiceBox fx:id="cb00" items="${choiceBoxItems}" prefWidth="150.0" GridPane.rowIndex="0" GridPane.columnIndex="0">