我有一个程序可以绘制一个可以在JPanel上驾驶的正方形。我有这个问题，每当我开车时，它会留下屏幕上的文物。当我开车时它会像JPanel Drawing Glitch那样。然后我在网上找到了一个解决方案，在我的paint（Graphics g）方法的开头，我应该放置一个“super.paintComponent（g）”。
完美无缺。但与此同时，我很享受有机会用这辆车进行绘图，所以我添加了一段代码，让我可以选择是否是super.paintComponent（g）'ing。但是，当我将这个代码转移到另一台计算机时，它不再有原始的错误，如果我愿意，不允许我绘制。我的问题是：我怎样才能复制这个错误，在我开车的时候把我以前的所有位置都拉到我身后？
这是我的代码。
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
/**
* Created by chris on 1/5/16.
*/
public class Game extends JPanel{
int[] size = new int[2];
private Car car;
private JFrame frame;
private final double speedScalar = .5;
private final double angleScalar = 5;
boolean isTurningLeft = false;
boolean isTurningRight = false;
boolean isSpeedingUp = false;
boolean isSlowingDown = false;
private static Toolkit tk = Toolkit.getDefaultToolkit();
private ArrayList<Point> rocks = new ArrayList<>();
public static final int width = tk.getScreenSize().width;
public static final int height = tk.getScreenSize().height;
public boolean isDrawing = false;
public Color[] colorChoices = {Color.black,Color.blue,Color.red,Color.orange,Color.pink} ;
public Color chosenColor = Color.black;
public Game(){
frame = new JFrame();
frame.setPreferredSize(new Dimension(width,height));
car = new Car(300,300);
setPreferredSize(new Dimension(width,height));
frame.add(this);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.addKeyListener(new KeyListener() {
@Override
public void keyTyped(KeyEvent e) {
System.out.println(e.getKeyChar());
switch(e.getKeyCode()){
case 37:
isTurningLeft = true;
isTurningRight = false;
break;
case 38:
isSpeedingUp = true;
isSlowingDown = false;
break;
case 39:
isTurningLeft = false;
isTurningRight = true;
break;
case 40:
isSpeedingUp = false;
isSlowingDown = true;
break;
}
}
@Override
public void keyPressed(KeyEvent e) {
switch(e.getKeyCode()){
case 37:
isTurningLeft = true;
isTurningRight = false;
break;
case 40:
isSpeedingUp = true;
isSlowingDown = false;
break;
case 39:
isTurningLeft = false;
isTurningRight = true;
break;
case 38:
isSpeedingUp = false;
isSlowingDown = true;
break;
case 32:
isDrawing = !isDrawing;
}
if(e.getKeyChar()=='c'){
chosenColor = colorChoices[(int)(Math.random()*5)];
} else if (e.getKeyChar()==' '){
isDrawing=!isDrawing;
}
}
@Override
public void keyReleased(KeyEvent e) {
switch(e.getKeyCode()){
case 37:
isTurningLeft = false;
break;
case 40:
isSpeedingUp = false;
break;
case 39:
isTurningRight = false;
break;
case 38:
isSlowingDown = false;
break;
}
}
});
Timer time = new Timer(1000/45, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if(isTurningRight){
car.setAngle(car.getAngle()+Math.toRadians(angleScalar));
} else if (isTurningLeft){
car.setAngle(car.getAngle()-Math.toRadians(angleScalar));
}
if(isSpeedingUp){
car.setSpeed(car.getSpeed()-speedScalar);
} else if (isSlowingDown){
car.setSpeed(car.getSpeed()+speedScalar);
}
if(car.getSpeed()<0){
car.setSpeed(0);
}
car.setX(car.getX() + (Math.cos(car.getAngle())*car.getSpeed()));
car.setY(car.getY() + (Math.sin(car.getAngle())*car.getSpeed()));
if(car.getX()<0){
car.setX(0);
car.setSpeed(0);
}
if(car.getX()>width){
car.setX(width);
car.setSpeed(0);
}
if(car.getY()<0){
car.setY(0);
car.setSpeed(0);
}
if(car.getY()>height){
car.setY(height);
car.setSpeed(0);
}
repaint();
}
});
double end = Math.random()*15;
frame.setVisible(true);
time.start();
}
public void paint(Graphics g){
if(!isDrawing) {
super.paintComponent(g);
}
/**
* Painting the car
*/
g.setColor(chosenColor);
double sin = Math.sin(car.getAngle());
double cos = Math.cos(car.getAngle());
int[] xPoints = {(int)car.getX(),(int)(car.getX()+cos*car.width),(int)(car.getX()-sin*car.length+cos*car.width),
(int)(car.getX()-sin*car.length)};
int[] yPoints = {(int)car.getY(),(int)(car.getY()+car.width*sin),(int)(car.getY()+cos*car.length+sin*car.width),
(int)(car.getY()+car.length*cos)};
Polygon car = new Polygon(xPoints,yPoints,4);
int[] recX = {400,450,450,400};
int[] recY = {400,400,450,450};
Rectangle2D test = new Rectangle(400,400,100,100);
((Graphics2D)g).fill(car);
((Graphics2D)g).fill(test);
if(car.intersects(test)){
chosenColor = Color.red;
}
tk.sync();
}
/**
* Created by chris on 1/5/16.
*/
public class Main {
public static void main(String[] args) {
Game g = new Game();
}
}
/**
* Created by chris on 1/5/16.
* Car class for my driving program.
*/
public class Car {
private double speed;
private double angle;
/**
* Coordinates on plane
*/
private double x;
private double y;
//For some reason this ends up being the size of the front
public int length = 10;
//and this ends up being the size of the sides.
public int width = 25;
public double getSpeed() {
return speed;
}
public void setSpeed(double speed) {
this.speed = speed;
}
public double getAngle() {
return angle;
}
public void setAngle(double angle) {
this.angle = angle;
}
public double getX() {
return x;
}
public void setX(double x) {
this.x = x;
}
public double getY() {
return y;
}
public void setY(double y) {
this.y = y;
}
public Car(double x, double y) {
this.x = x;
this.y = y;
speed = 0;
angle = 0;
}
}