JAVAFX UI CONTROLS AND MULTIMEDIA - Introduction to Java Programming: Comprehensive Version - page 635

javafx.scene.control.Labeled

The getter and setter methods for property
values and a getter for property itself are provided
in the class, but omitted in the UML diagram for brevity.

javafx.scene.control.ButtonBase

-onAction: ObjectProperty<EventHandler
<ActionEvent>>

Defines a handler for handling a button's action.

javafx.scene.control.CheckBox

-selected: BooleanProperty Indicates whether this check box is checked.

+CheckBox()
+CheckBox(text: String)

Creates an empty check box.
Creates a check box with the specified text.

F IGURE 16.7

CheckBox contains the properties inherited from ButtonBase and Labeled .

When a check box is clicked (checked or unchecked), it fires an ActionEvent . To see if
a check box is selected, use the isSelected() method.
We now write a program that adds two check boxes named Bold and Italic to the pre-
ceding example to let the user specify whether the message is in bold or italic, as shown in
Figure 16.8.

VBox
containing
two check
boxes

F IGURE 16.8

The program demonstrates check boxes.

There are at least two approaches to writing this program. The first is to revise the preced-
ing ButtonDemo class to insert the code for adding the check boxes and processing their
events. The second is to define a subclass that extends ButtonDemo . Please implement the
first approach as an exercise. Listing 16.3 gives the code to implement the second approach.

L ISTING 16.3

CheckBoxDemo.java
1 import javafx.event.ActionEvent;
2 import javafx.event.EventHandler;
3 import javafx.geometry.Insets;
4 import javafx.scene.control.CheckBox;
5 import javafx.scene.layout.BorderPane;
6 import javafx.scene.layout.VBox;
7 import javafx.scene.text.Font;
8 import javafx.scene.text.FontPosture;
9 import javafx.scene.text.FontWeight;
10
11 public class CheckBoxDemo extends ButtonDemo {
12 @Override // Override the getPane() method in the super class
13 protected BorderPane getPane() {
14 BorderPane pane = super .getPane();

Application

ButtonDemo

CheckBoxDemo

override getPane()
invoke super.getPane()