LISTS, STACKS, QUEUES, AND PRIORITY QUEUES - Introduction to Java Programming: Comprehensive Version - page 778

Each ball has its state: the x -, y -coordinates, color, and direction to move. You can
define a class named Ball that extends javafx.scene.shape.Circle . The x -,
y -coordinates and the color are already defined in Circle . When a ball is created, it
starts from the upper-left corner and moves downward to the right. A random color is
assigned to a new ball.
The MultiplBallPane class is responsible for displaying the ball and the
MultipleBounceBall class places the control components and implements the control. The
relationship of these classes is shown in Figure 20.9. Listing 20.6 gives the program.

javafx.scene.shape.Circle javafx.scene.layout.Pane javafx.application.Application

m1 11

Ball MultipleBallPane MultipleBounceBall

dx: double
dy: double

-animation: Timeline

+MultipleBallPane()
+play(): void
+pause(): void
+increaseSpeed(): void
+decreaseSpeed(): void
+rateProperty(): Double
Property
+moveBall(): void

+Ball (x: double, y: double
radius: double,
color: color)

F IGURE 20.9

MultipleBounceBall contains MultipleBallPane , and MultipleBallPane contains Ball .

L ISTING 20.6

MultipleBounceBall.java
1 import javafx.animation.KeyFrame;
2 import javafx.animation.Timeline;
3 import javafx.application.Application;
4 import javafx.beans.property.DoubleProperty;
5 import javafx.geometry.Pos;
6 import javafx.scene.Node;
7 import javafx.stage.Stage;
8 import javafx.scene.Scene;
9 import javafx.scene.control.Button;
10 import javafx.scene.control.ScrollBar;
11 import javafx.scene.layout.BorderPane;
12 import javafx.scene.layout.HBox;
13 import javafx.scene.layout.Pane;
14 import javafx.scene.paint.Color;
15 import javafx.scene.shape.Circle;
16 import javafx.util.Duration;
17
18 public class MultipleBounceBall extends Application {
19 @Override // Override the start method in the Application class
20 public void start(Stage primaryStage) {
21 MultipleBallPane ballPane = new MultipleBallPane();
22 ballPane.setStyle( "-fx-border-color: yellow" );
23
24 Button btAdd = new Button( "+" );

create a ball pane
set ball pane border

create buttons