你不是在构建EDT http://java.sun.com/docs/books/tutorial/uiswing/concurrency/initial.html。一个实例javax.swing.Timer http://java.sun.com/javase/6/docs/api/javax/swing/Timer.html使这变得容易，因为操作事件处理程序在EDT http://java.sun.com/docs/books/tutorial/uiswing/concurrency/initial.html.
附录 1：你may决定你需要双缓冲 http://java.sun.com/docs/books/tutorial/extra/fullscreen/doublebuf.html，但首先将下面的代码与您的代码进行比较并查看。如果你走那条路，你可能会看看这个tutorial http://www.stumbleupon.com/su/8wGoxm/www.cokeandcode.com/info/tut2d.html.
附录 2：下面的示例展示了如何维护离屏缓冲区，但有时使用JPanel(boolean isDoubleBuffered) http://java.sun.com/javase/6/docs/api/javax/swing/JPanel.html#JPanel%28boolean%29构造函数具有类似的效果。
import java.awt.event.KeyAdapter;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import static java.awt.Color.*;
/** @see http://stackoverflow.com/questions/2114455 */
public class GUI extends JPanel implements ActionListener {
int x, y, x1, y1, x2, y2, changeY, changeY2;
int changeX = 1; int changeX2 = 1;
Timer t = new Timer(100, this);
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new GUI(true).display();
}
});
}
public GUI(boolean doubleBuffered) {
super(doubleBuffered);
this.setPreferredSize(new Dimension(320, 240));
}
private void display() {
JFrame frame = new JFrame("GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.addKeyListener(new KeyListener());
frame.add(this);
frame.pack();
frame.setVisible(true);
t.start();
}
@Override
public void paintComponent(Graphics g) {
g.setColor(WHITE);
g.fillRect(0, 0, getWidth(), getHeight());
g.setColor(BLACK);
g.fillRect(x, y, 100, 100);
g.setColor(RED);
g.fillRect(x1, y1, 50, 50);
g.setColor(BLUE);
g.fillRect(x2, y2, 25, 25);
}
public void change() {
if (x1 >= x + 50 && changeY == 0 && changeX == 1) {
changeX = 0;
changeY = 1;
} else if (y1 >= y + 50 && changeX == 0 && changeY == 1) {
changeX = -1;
changeY = 0;
} else if (x1 <= x && changeX == -1 && changeY == 0) {
changeX = 0;
changeY = -1;
} else if (y1 <= y && changeY == -1 && changeX == 0) {
changeX = 1;
changeY = 0;
}
x1 += changeX * 5;
y1 += changeY * 5;
}
public void change2() {
if (x2 >= x1 + 25 && changeY2 == 0 && changeX2 == 1) {
changeX2 = 0;
changeY2 = 1;
} else if (y2 >= y1 + 25 && changeX2 == 0 && changeY2 == 1) {
changeX2 = -1;
changeY2 = 0;
} else if (x2 <= x1 && changeX2 == -1 && changeY2 == 0) {
changeX2 = 0;
changeY2 = -1;
} else if (y2 <= y1 && changeY2 == -1 && changeX2 == 0) {
changeX2 = 1;
changeY2 = 0;
}
x2 += changeX2 * 2;
y2 += changeY2 * 2;
}
@Override
public void actionPerformed(ActionEvent e) {
change();
change2();
repaint();
}
private class KeyListener extends KeyAdapter {
@Override
public void keyPressed(KeyEvent e) {
int d = 5;
if (e.getKeyCode() == KeyEvent.VK_UP) {
if (y - d >= 0) {
y -= d;
y1 -= d;
y2 -= d;
}
}
if (e.getKeyCode() == KeyEvent.VK_DOWN) {
if (y + 100 + d <= getHeight()) {
y += d;
y1 += d;
y2 += d;
}
}
if (e.getKeyCode() == KeyEvent.VK_LEFT) {
if (x - d >= 0) {
x -= d;
x1 -= d;
x2 -= d;
}
}
if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
if (x + 100 + d <= getWidth()) {
x += d;
x1 += d;
x2 += d;
}
}
}
}
}
