BouncingBallThread

BouncingBallThread.java

import acm.program.*;
 
public class BouncingBallUsingThread extends GraphicsProgram {
 
    /** Initialize the ball and its velocity components */
    public void init() {
        ball = new RunnableGBall(BALL_RADIUS);
        ball.setEnclosureSize(getWidth(), getHeight());
        ball.setVelocity(2, 1);
        add(ball, getWidth() / 2, getHeight() /2 );
    }
 
    /** Create a thread to bounce the ball */
    public void run() {
        waitForClick();
        new Thread(ball).start();
    }
 
    /* Private constants */
    private static final double BALL_RADIUS = 10;
 
    /* Private instance variables */
    private RunnableGBall ball;
 
    private static final long serialVersionUID = 1;
}

RunnableGBall.java

이 부분의 본문은 RunnableGBall입니다.

public class RunnableGBall extends GBall implements Runnable {
 
	/** Creates a new ball with radius r centered at the origin */
	public RunnableGBall(double r) {
		super(r);
	}
 
	public void setEnclosureSize(double width, double height) {
		enclosureWidth = width;
		enclosureHeight = height;
	}
 
	public void setVelocity(double vx, double vy) {
		dx = vx;
		dy = vy;
	}
 
	@Override
	public void run() {
		// TODO Auto-generated method stub
		while (true) {
			advanceOneTimeStep();
			pause(PAUSE_TIME);
		}
	}
 
	private void advanceOneTimeStep() {
		double bx = getX();
		double by = getY();
		double r = getWidth() / 2;
		if (bx < r || bx > enclosureWidth - r) dx = -dx;
		if (by < r || by > enclosureHeight - r) dy = -dy;
		move(dx, dy);
	}
 
	/* Private constants */
	private static final int PAUSE_TIME = 20;
 
	/* Private instance variables */
	private double enclosureWidth;
	private double enclosureHeight;
	private double dx;
	private double dy;
}