java 无窗口边框并可以拖动窗口

本程序用 visual editor 开发
想安装 VE（eclipse 的 java 图形开发插件） 请看: http://wuzijingaip.iteye.com/admin/blogs/457976

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;

import javax.swing.JFrame;

public class test extends JFrame {
	private int xx, yy;

	private boolean isDraging = false;

	public test() {
		setUndecorated(true); // 没有标题栏
		setSize(200, 200);
		setVisible(true);
		this.addMouseListener(new MouseAdapter() {
			public void mousePressed(MouseEvent e) {
				isDraging = true;
				xx = e.getX();
				yy = e.getY();
			}

			public void mouseReleased(MouseEvent e) {
				isDraging = false;
			}
		});
		this.addMouseMotionListener(new MouseMotionAdapter() {
			public void mouseDragged(MouseEvent e) {
				if (isDraging) {
					int left = getLocation().x;
					int top = getLocation().y;
					setLocation(left + e.getX() - xx, top + e.getY() - yy);
				}
			}
		});
	}

	public static void main(String[] args) {
		test t = new test();
		t.setDefaultCloseOperation(3);
	}
}