我有一个项目，一个圆圈随机的x和y值以及选定的颜色，但是当用户按下空格键时，必须更改圆圈的颜色。我的圆圈同时移动x和y坐标，我想按空格按钮时更改圆圈的颜色。但是当我按下它时它不起作用。它具有原始颜色。那么我怎样才能使这段代码正确？
public class c {
private int x,y,r;
private Color co;
private int Re,G,B;
private Random ran;
public c() {
// TODO Auto-generated constructor stub
ran= new Random();
x=100;
y=50;
r= ran.nextInt(200)+50;
Re=ran.nextInt(255);
G=ran.nextInt(255);
B=ran.nextInt(255);
co= new Color(Re,G,B);
}
public int getRe() {
return Re;
}
public int getG() {
return G;
}
public int getB() {
return B;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public int getR() {
return r;
}
public void setCo(int Re,int G,int B) {
co= new Color(Re,G,B);
}
public Color getCo() {
return co;
}
public Random getRan() {
return ran;
}
public void setX(int x) {
this.x=x;
}
public void setY(int y) {
this.y=y;
}
}
public class Circle extends JFrame implements ActionListener,KeyListener{
private Timer timer;
private int x,y,a=5,b=5;
private Random rand;
c circ = new c();
public Circle() {
setLayout(new BorderLayout());
x=circ.getX();
y=circ.getY();
timer=new Timer(50,this);
timer.start();
addKeyListener(this);
setSize(550,550);
setVisible(true);
}
public void paint(Graphics g) {
super.paint(g);
g.fillOval(x,y,100,100);
g.setColor(circ.getCo());
}
public static void main(String[]args) {
new Circle();
}
@Override
public void actionPerformed(ActionEvent e) {
moveWithTimer();
repaint();
}
public void moveWithTimer() {
x=x+b;
y=y+a;
if(x<0) {
b=5;
}
if(x+50>500) {
b=-5;
}
if(y<0){
a=5;
}
if(y+50>500) {
a=-5;
}
}
@Override
public void keyPressed(KeyEvent e) {
// TODO Auto-generated method stub
if(e.getKeyCode()==e.VK_SPACE) {
circ.setCo(rand.nextInt(255),rand.nextInt(255),rand.nextInt(255));
}
}
@Override
public void keyReleased(KeyEvent e) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent e) {
// TODO Auto-generated method stub
}
}
答案 0 :(得分：2)
我建议您在绘制圆圈之前在paint（g）中设置图形对象的颜色。
public void paint(Graphics g) {
super.paint(g);
g.setColor(circ.getCo());
g.fillOval(x,y,100,100);
}
通常，您不应该覆盖JFrame的paint（）方法。相反，创建一个JPanel，将其添加到您的框架并覆盖面板的paintComponent（）方法。
答案 1 :(得分：2)
但是当我按下它时它不起作用。它具有原始颜色。那么我怎样才能使这段代码正确？
KeyListener变幻莫测，更好地使用Key Bindings API来克服与KeyListener
作为一般经验法则，您不应该覆盖paint等顶级容器的JFrame，它们是复合组件，而且它只是一个真正的混乱。
相反，请先使用JPanel并覆盖它的paintComponent方法。它通常更灵活。有关详细信息，请查看Performing Custom Painting。
您的动作代码有误。您将圆类的x / y值分配给其他一些变量，这里的问题是，更改这些变量的值对圆圈类中的变量没有影响，相反，您需要分配回来......
public void moveWithTimer() {
int x = circ.getX();
int y = circ.getY();
x = x + b;
y = y + a;
if (x < 0) {
b = 5;
}
if (x + 50 > 500) {
b = -5;
}
if (y < 0) {
a = 5;
}
if (y + 50 > 500) {
a = -5;
}
circ.setX(x);
circ.setY(y);
}
你的＆＃34;圈＆＃34; class也可以使用其他几种方法。一个随机化颜色（它已经有一个Random对象，也可以使用它）和一个来绘制对象。
public class Circle {
//...
public void paint(Graphics2D g2d) {
g2d.setColor(co);
g2d.fillOval(x, y, r * 2, r * 2);
}
//...
public void randomColor() {
setCo(ran.nextInt(255), ran.nextInt(255), ran.nextInt(255));
}
//...
}
如果是我，我也很想添加move方法，但这就是我;）
作为一个可运行的例子......
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.Random;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private Timer timer;
private int a = 5, b = 5;
private Random rand;
private Circle circ = new Circle();
public TestPane() {
timer = new Timer(50, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
moveWithTimer();
repaint();
}
});
timer.start();
InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW);
ActionMap am = getActionMap();
im.put(KeyStroke.getKeyStroke(KeyEvent.VK_SPACE, 0), "spaced");
am.put("spaced", new AbstractAction() {
@Override
public void actionPerformed(ActionEvent e) {
circ.randomColor();
repaint();
}
});
}
public void moveWithTimer() {
int x = circ.getX();
int y = circ.getY();
x = x + b;
y = y + a;
if (x < 0) {
b = 5;
}
if (x + 50 > 500) {
b = -5;
}
if (y < 0) {
a = 5;
}
if (y + 50 > 500) {
a = -5;
}
circ.setX(x);
circ.setY(y);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
circ.paint(g2d);
g2d.dispose();
}
}
public class Circle {
private int x, y, r;
private Color co;
private int Re, G, B;
private Random ran;
public Circle() {
// TODO Auto-generated constructor stub
ran = new Random();
x = 100;
y = 50;
r = ran.nextInt(50) + 50;
Re = ran.nextInt(255);
G = ran.nextInt(255);
B = ran.nextInt(255);
co = new Color(Re, G, B);
}
public void paint(Graphics2D g2d) {
g2d.setColor(co);
g2d.fillOval(x, y, r * 2, r * 2);
}
public int getRe() {
return Re;
}
public int getG() {
return G;
}
public int getB() {
return B;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public int getR() {
return r;
}
public void randomColor() {
setCo(ran.nextInt(255), ran.nextInt(255), ran.nextInt(255));
}
public void setCo(int Re, int G, int B) {
co = new Color(Re, G, B);
}
public Color getCo() {
return co;
}
public Random getRan() {
return ran;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
}
}