有四道题，应该是Java开发实战1200里面的，求个代码

这里有个设置界面可以隐藏的方法，也就是第四题：

// 设置界面可以拖动的方法
	Point loc = null;
	Point tmp = null;
	boolean isDragged = false;

	private void setDragable() {
		this.addMouseListener(new java.awt.event.MouseAdapter() {
			public void mouseReleased(java.awt.event.MouseEvent e) {
				isDragged = false;
				QQMain.this.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
				if(QQMain.this.getLocation().y<0){
					try {
						Thread.sleep(500);
					} catch (InterruptedException e1) {
						// TODO Auto-generated catch block
						e1.printStackTrace();
					}
					QQMain.this.setLocation(QQMain.this.getLocation().x, -590);
				}
			}

			public void mousePressed(java.awt.event.MouseEvent e) {
				tmp = new Point(e.getX(), e.getY());

				isDragged = true;
				QQMain.this.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
			}
			
			//鼠标进入事件
			@Override
			public void mouseEntered(MouseEvent e) {
				if(QQMain.this.getLocation().y<0){
					try {
						Thread.sleep(500);
					} catch (InterruptedException e1) {
						// TODO Auto-generated catch block
						e1.printStackTrace();
					}
					QQMain.this.setLocation(QQMain.this.getLocation().x, 20);
				}
			}
			
		});
		this.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
			public void mouseDragged(java.awt.event.MouseEvent e) {
				if (isDragged) {
					loc = new Point(QQMain.this.getLocation().x + e.getX()
							- tmp.x, QQMain.this.getLocation().y + e.getY()
							- tmp.y);
					
					QQMain.this.setLocation(loc);//设置当前窗口的位置
				}
			}
		});
	}