版本1:小球水平撞击桌面反弹
import java.awt.*;
import javax.swing.*;
public class BallGame extends JFrame{
Image ball = Toolkit.getDefaultToolkit().getImage("images/ball.png");
Image desk = Toolkit.getDefaultToolkit().getImage("images/desk.jpg");
double x = 100;//小球的横坐标
double y = 100;//小球的纵坐标
boolean right = true;//方向
//画窗口的方法
public void paint(Graphics g) {
System.out.println("窗口被画了一次");
g.drawImage(desk, 0, 0, null);
g.drawImage(ball, (int)x, (int)y, null);
if(right){
x = x + 10;
}else {
x = x - 10;
}
if(x>856-40-30){//856是窗口宽度,40是桌子边框的宽度,30是小球的直径
right = false;
}
if(x<40){
right = true;
}
}
//窗口加载
void launchFrame() {
setSize(856,500);//窗口的长宽
setLocation(50, 50);//窗口的左上角点相对于原点定位
setVisible(true);
//重画窗口,每秒画25次
while(true) {
repaint();
try {
Thread.sleep(40);//40ms 1秒=1000毫秒
}catch(Exception e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
System.out.print("");
BallGame game = new BallGame();
game.launchFrame();
}
}
版本二:小球任意角度撞击桌面
import java.awt.*;
import javax.swing.*;
public class BallGame extends JFrame{
Image ball = Toolkit.getDefaultToolkit().getImage("images/ball.png");
Image desk = Toolkit.getDefaultToolkit().getImage("images/desk.jpg");
double x = 100;//小球的横坐标
double y = 100;//小球的纵坐标
double degree = 3.14/3; //弧度。此处就是:60度
//画窗口的方法
public void paint(Graphics g) {
System.out.println("窗口被画了一次");
g.drawImage(desk, 0, 0, null);
g.drawImage(ball, (int)x, (int)y, null);
x = x + 10*Math.cos(degree);
y = y + 10*Math.sin(degree);
if(y>500-40-30||y<40+40){//500是窗口高度;40是桌子边框;30是球直径;最后一个40是标题栏的高度
degree = -degree;
}
//碰到左右边界
if(x<40||x>856-40-30) {
degree = 3.14 - degree;
}
}
//窗口加载
void launchFrame() {
setSize(856,500);//窗口的长宽
setLocation(50, 50);//窗口的左上角点相对于原点定位
setVisible(true);
//重画窗口,每秒画25次
while(true) {
repaint();
try {
Thread.sleep(40);//40ms 1秒=1000毫秒
}catch(Exception e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
System.out.print("");
BallGame game = new BallGame();
game.launchFrame();
}
}