修改drawBall方法使得球在窗口中出现public void paintComponent(Graphics page){ super.paintComponent(page); drawBall(); //绘画一个球 drawPaddle(); //绘画一个桨 drawAllBricks();//绘画所有砖块 } private void drawBall(){ GOval Ball=new GOval(ballX,ballY,BALL_RADIUS,BALL_RADIUS); Ball.setFillColor(Color.BLACK); }
时间: 2024-03-22 12:37:58 浏览: 17
要使球在窗口中出现,需要将drawBall方法中创建的GOval对象添加到窗口中。可以将drawBall方法修改如下:
```java
private void drawBall() {
GOval ball = new GOval(ballX, ballY, BALL_RADIUS * 2, BALL_RADIUS * 2);
ball.setFilled(true);
ball.setColor(Color.BLACK);
add(ball); // 将球添加到窗口中
}
```
修改后,paintComponent方法中的drawBall()方法会在窗口中绘制一个黑色的球。注意,为了让球在窗口中显示,需要将它添加到窗口中,可以使用add方法将球添加到BreakoutPanel1类中。
相关问题
怎么申明一个新的GRect类的对象,然后在窗口展示;已知存在的代码如下,请补全球和球拍的绘制public BreakoutPanel1(){ Random rgen=new Random(); vx=rgen.nextDouble()*2+1; if(new Random().nextBoolean())vx=-vx; ballX = (int)(Math.random() * (APPLICATION_WIDTH - BALL_RADIUS * 2)); ballY = (int)(Math.random() * (APPLICATION_HEIGHT - BALL_RADIUS * 2)); ActionListener listener=new TimePainter(); ballMoveTimer = new Timer(DELAY,listener); ballMoveTimer.start(); paddleX = (APPLICATION_WIDTH-PADDLE_WIDTH)/2; paddleY = APPLICATION_HEIGHT-PADDLE_Y_OFFSET-PADDLE_HEIGHT; setPreferredSize(new Dimension(APPLICATION_WIDTH, APPLICATION_HEIGHT));//定义窗口组件大小 setBackground(Color.white); addMouseMotionListener(new MouseCoordinate()); } public void paintComponent(Graphics page){ super.paintComponent(page); drawBall(); //绘画一个球 drawPaddle(); //绘画一个桨 drawAllBricks();//绘画所有砖块 } private void drawBall(){ GOval Ball=new GOval(ballX,ballY,BALL_RADIUS,BALL_RADIUS); Ball.setFillColor(Color.BLACK); } private void drawPaddle(){ GRect Paddle = new GRect(paddleX, paddleY, PADDLE_WIDTH, PADDLE_HEIGHT); Paddle.setFillColor(Color.BLACK); }
要声明一个新的GRect类的对象,可以使用以下代码:
```java
GRect rect = new GRect(x, y, width, height);
```
其中,x、y是矩形左上角的坐标,width、height是矩形的宽度和高度。
要在窗口展示这个对象,需要将它添加到BreakoutPanel1类中的paintComponent方法中,例如:
```java
public void paintComponent(Graphics page){
super.paintComponent(page);
drawBall();
drawPaddle();
drawAllBricks();
add(rect); // 将新的矩形对象添加到窗口中
}
```
注意,为了让新的矩形对象在窗口中显示,需要将它添加到BreakoutPanel1类中的paintComponent方法中,并且需要在该方法中调用add方法将对象添加到窗口中。
请你写一个程序实现动态的球在窗内运动,碰到边框时进行反弹
好的,以下是一个简单的程序实现动态的球在窗内运动,碰到边框时进行反弹的效果:
```java
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class BallTest extends JPanel {
public static final int APPLICATION_WIDTH = 400;
public static final int APPLICATION_HEIGHT = 600;
private int ballX, ballY;
private static final int BALL_RADIUS = 10;
private static final int DELAY = 20;
private Timer ballMoveTimer;
private double vx, vy;
public BallTest() {
ballX = APPLICATION_WIDTH / 2;
ballY = APPLICATION_HEIGHT / 2;
Random rgen = new Random();
vx = rgen.nextDouble() * 2 + 1;
vy = rgen.nextDouble() * 2 + 1;
if (new Random().nextBoolean()) vx = -vx;
if (new Random().nextBoolean()) vy = -vy;
ActionListener listener = new TimePainter();
ballMoveTimer = new Timer(DELAY, listener);
ballMoveTimer.start();
setPreferredSize(new Dimension(APPLICATION_WIDTH, APPLICATION_HEIGHT));
setBackground(Color.white);
}
public void paintComponent(Graphics page) {
super.paintComponent(page);
drawBall(page);
}
private void drawBall(Graphics page) {
Graphics2D pages = (Graphics2D) page;
Ellipse2D currentE = new Ellipse2D.Double(ballX, ballY, BALL_RADIUS, BALL_RADIUS);
pages.setColor(Color.BLACK);
pages.fill(currentE);
}
class TimePainter implements ActionListener {
public void actionPerformed(ActionEvent event) {
if (ballX + BALL_RADIUS > APPLICATION_WIDTH || ballX < 0) {
vx = -vx;
}
if (ballY + BALL_RADIUS > APPLICATION_HEIGHT || ballY < 0) {
vy = -vy;
}
ballX += vx;
ballY += vy;
repaint();
}
}
public static void main(String[] args) {
JFrame frame = new JFrame("Ball Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BallTest panel = new BallTest();
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
}
}
```
程序窗口内会绘制一个球,球的运动方向和速度是随机生成的,碰到边框时会进行反弹。程序中使用了一个 `Timer` 类来控制球的运动,每隔一段时间就会触发 `actionPerformed` 方法,在该方法中进行球的位置更新和重绘。