Java GridLayout在三个相同Panel中，只有一个显示正确了，请大神进来看看

IWontQuit 2015-04-20 06:40:36

我编写了一个日历的程序，在一个Panel上初始化三个相同的日历，这三个日历的panel都设置为Gridlayout(6,7)布局，为什么只有一个panel显示正确了，其他的都少显示一列？

private class JP3 extends JPanel{

		private static final long serialVersionUID = 1L;

		private int offset=0;

        private LabelManager labelmanager;

    	public JP3(int pos){

//            super(new GridLayout(6,7));

            this.setLayout(new GridLayout(6,7));

            this.setPreferredSize(new Dimension(width,170));

            offset=pos-1;

            labelmanager=lm[pos];

            initJP3();

        }

        private void initJP3(){

            updateDate();

        }

        public void updateDate(){

            this.removeAll();

            labelmanager.clear();

            Date temp=select.getTime();

            Calendar select=Calendar.getInstance();

            select.setTime(temp);

            select.add(Calendar.MONTH, offset);                 //根据offset改变日期

            select.set(Calendar.DAY_OF_MONTH,1);

            int index=select.get(Calendar.DAY_OF_WEEK);

            for(int n=0;n<index;n++){                           //在本月1号开始之前添加空白标签

            	JLabel blank=new JLabel();

            	this.add(blank);

            }

            int sum=select.getActualMaximum(Calendar.DAY_OF_MONTH);

            for(int i=0;i<sum;i++){

                

            	labelmanager.addLabel(new MyLabel(select.get(Calendar.YEAR),

                        select.get(Calendar.MONTH),select.get(Calendar.DAY_OF_MONTH),offset));

                select.add(Calendar.DAY_OF_MONTH,1);

            }

            for(MyLabel my:labelmanager.getLabels()){

                this.add(my);

            }

            select.setTime(temp);                              //恢复到当前日期

        }

    }

private class MyLabel extends JLabel implements Comparator<MyLabel>,MouseListener{

        /**

		 * 

		 */

		private static final long serialVersionUID = 1L;

		private int year,month,day;

        private boolean isSelected;

        private int offset;

        @SuppressWarnings("unused")

		public MyLabel(){

        	

        }

       public MyLabel(int year,int month,int day,int offset){

            super(""+day,JLabel.CENTER);

            this.offset=offset;

            this.year=year;

            this.day=day;

            this.month=month;

            this.setFont(font);

       }

}

private class LabelManager{

        private List<MyLabel> list;

        public LabelManager(){

            list=new ArrayList<MyLabel>();

        }

        public void addLabel(MyLabel my){

            list.add(my);

        }

}