EVENT-DRIVEN PROGRAMMING AND ANIMATIONS - Introduction to Java Programming: Comprehensive Version - page 617

Here are the major steps to write this program:

1. Define a subclass of Pane named BallPane to display a ball bouncing, as shown in
Listing 15.17.

2. Define a subclass of Application named BounceBallControl to control the bounc-
ing ball with mouse actions, as shown in Listing 15.18. The animation pauses when the
mouse is pressed and resumes when the mouse is released. Pressing the UP and DOWN
arrow keys increases/decreases animation speed.

The relationship among these classes is shown in Figure 15.23.

javafx.scene.layout.Pane javafx.application.Application

1 1

BallPane BounceBallControl

-x: double
-y: double
-dx: double
-dy: double
-radius: double
-circle: Circle
-animation: Timeline

+BallPane()
+play(): void
+pause(): void
+increaseSpeed(): void
+decreaseSpeed(): void
+rateProperty(): DoubleProperty
+moveBall(): void

F IGURE 15.23

BounceBallControl contains BallPane .

L ISTING 15.17

BallPane.java
1 import javafx.animation.KeyFrame;
2 import javafx.animation.Timeline;
3 import javafx.beans.property.DoubleProperty;
4 import javafx.scene.layout.Pane;
5 import javafx.scene.paint.Color;
6 import javafx.scene.shape.Circle;
7 import javafx.util.Duration;
8
9 public class BallPane extends Pane {
10

public final double radius = 20 ;

11 private double x = radius, y = radius;

12 private double dx = 1 , dy = 1 ;

13 private Circle circle = new Circle(x, y, radius);

14 private Timeline animation;

15
16 public BallPane() {
17 circle.setFill(Color.GREEN); // Set ball color
18 getChildren().add(circle); // Place a ball into this pane