Getting a Jump Start in JavaFX - JavaFX 8: A Definitive Guide to Building Desktop, Mobile, and Embedded Java Clients - page 27

What causes selectedIndexProperty of the genreSelectionModel to change? To see the answer to this, we
have to revisit some code in Listing 1-3. In the following code snippet, the setItems method of ChoiceBox is used to
populate the ChoiceBox with items that each contain a genre.

genreChoiceBox = new ChoiceBox();
genreChoiceBox.setLayoutX(204);
genreChoiceBox.setLayoutY(154);
genreChoiceBox.setPrefWidth(93);
genreChoiceBox.setItems(acModel.genres);

This snippet from the model code in Listing 1-4 contains the collection to which the ComboBox items are bound:

/**
* List of some musical genres
*/
public ObservableList genres = FXCollections.observableArrayList(
"Chamber",
"Country",
"Cowbell",
"Metal",
"Polka",
"Rock"
);

When the user chooses a different item in the ChoiceBox , the invalidationListener is invoked. Looking again
at the code in the invalidationListener , you'll see that the value of the selectedDBs property changes, which as you
may recall, is bidirectionally bound to the slider. This is why the slider moves when you select a genre in the combo
box. Go ahead and test this by running the Audio Config program.

■ associating the items property of the ChoiceBox with an ObservableList causes the items in the ChoiceBox
to be automatically updated when the elements in the underlying collection are modified.

Note

Surveying JavaFX Features
We close this chapter by surveying many of the features of JavaFX, some of which are a review for you. We do this by
describing several of the more commonly used packages and classes in the Java SDK API.
The javafx.stage package contains the following:

Stage class, which is the top level of the UI containment hierarchy for any JavaFX
application, regardless of where it is deployed (e.g., the desktop, a browser, or a cell phone).

• The

Screen class, which represents the displays on the machine in which a JavaFX program is
running. This enables you to get information about the screens, such as size and resolution.

• The