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我对Java和编程一般都很陌生,所以我试着编写一个简单的程序,其唯一的工作是用箭头键移动球并用空格键跳跃。程序编译但球不动。当我按下一个按钮时,为什么我的小程序中球没有移动?
我可能没有完全理解Applet的原则,你能向我解释我犯的错误吗?
小程序:
package test_game;
import java.applet.Applet;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
public class Starting_Point extends Applet implements Runnable, KeyListener {
private static final long serialVersionUID = 1L;
private static final int WIDTH = 700;
private static final int HEIGHT = 300;
Character Phil;
Thread thread;
@Override
public void init() {
setSize(WIDTH,HEIGHT);
Phil = new Character(50, 200);
}
@Override
public void start() {
thread = new Thread(this);
thread.start();
}
public void run() {
while (true) {
repaint();
}
}
@Override
public void paint(Graphics arg0) {
Phil.paint(arg0);
}
@Override
public void keyPressed(KeyEvent arg0) {
switch (arg0.getKeyCode()) {
case (KeyEvent.VK_LEFT): Phil.setX(Phil.getX() - Phil.getDx());
break;
case (KeyEvent.VK_RIGHT): Phil.setX(Phil.getX() + Phil.getDx());
break;
case (KeyEvent.VK_SPACE): Phil.setDy(Character.gravity * Character.dt);
Phil.setY(Phil.getY() + .5*Character.gravity*Character.dt*Character.dt + Phil.getDy()*Character.dt + Character.jump);
break;
}
}
@Override
public void keyReleased(KeyEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent arg0) {
// TODO Auto-generated method stub
}
}
字符类别:
package test_game;
import java.awt.Color;
import java.awt.Graphics;
public class Character {
private int x;
private int y;
private int radius = 10;
Graphics g;
public static final int gravity = 15;
private static final double dx = 4;
public double dy;
public static final double dt = .2;
public static final int jump = 30;
public Character(int x, int y) {
this.x = x;
this.y = y;
}
public void setX(double d) {
this.x = (int) d;
}
public void setY(double d) {
this.y = (int) d;
}
public double getDx() {
return dx;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public void setDy(double dy) {
this.dy = dy;
}
public double getDy() {
return dy;
}
public void paint(Graphics g) {
g.setColor(Color.black);
g.fillOval(x, y, radius, radius);
}
}
*“我试图写一个简单的程序..”*小程序从来不简单。先制作相框。 1)为什么要编写一个小程序?如果是由于老师指定它,请将它们转介给[为什么CS教师应该**停止**教Java applets](http://programmers.blogoverflow.com/2013/05/why-cs-teachers-should -stop教学-java的小应用程序/)。 2)为什么使用AWT?看到[这个答案](http://stackoverflow.com/questions/6255106/java-gui-listeners-without-awt/6255978#6255978)有很多很好的理由放弃AWT使用组件有利于Swing。 – 2014-11-09 03:23:42