如何能改变gridview上的数字的颜色？？？急啊...


   现在要做一个功能，如上图，点击‘月’的时候，显示一个月的日期，如果当天有事情的话，该天的字体显示成红色！这个月中有事情的天数，放在一个数组中。如：第1天和第10天有事，则data[]={1,10}。整个这块是用个gridview做出来的，现在就是不晓得如何让字体变红？？？急死人了！！高手帮帮忙啊....
    下面是我的代码:
        Map<String, Object> ite;
List<Map<String, Object>> sDay;


//点击月时的日历显示
public void monthCalendar(){
//星期
       List<Map<String, Object>> items = new ArrayList<Map<String,Object>>();
       for (int i = 0; i < 7; i++) {
         Map<String, Object> item = new HashMap<String, Object>();
         item.put("textItem", week[i]);
         items.add(item);
       }
       SimpleAdapter adapter=new SimpleAdapter(this, items, R.layout.grid_item, new String[]{"textItem"},new int []{R.id.text_item});
       llweeks.setAdapter(adapter);
       
       //一个月中的天
       
       sDay = new ArrayList<Map<String,Object>>();
       setCalender(year,month);
       
       SimpleAdapter adapt=new SimpleAdapter(this, sDay, R.layout.grid_item, new String []{"textItem"},new int []{R.id.text_item});
       lldays.setAdapter(adapt);
       
}

public void setCalender(int year,int month)
    {
      calendar.set(year,month-1,1);              
      
      weeknum=calendar.get(Calendar.DAY_OF_WEEK)-1;
      if(weeknum>0){
       for(int i=0;i<weeknum;i++){
       ite = new HashMap<String, Object>();
       ite.put("textItem", "");
       sDay.add(ite);
       }
      }
      if(month==1||month==3||month==5||month==7
                         ||month==8||month==10||month==12)
         {
         monthday=31;
             arrangenum(weeknum,31);         
         }
      else if(month==4||month==6||month==9||month==11)
         {
       monthday=30;
             arrangenum(weeknum,30);
         }
      else if(month==2)
         {
          if((year%4==0&&year%100!=0)||(year%400==0))  
            {
           monthday=29;
              arrangenum(weeknum,29);
            }
          else
            {
           monthday=28;
              arrangenum(weeknum,28);
            }
        }
    }

    public void arrangenum(int weeknum,int monthnum)
    {
       for(int i=weeknum,n=1;i<weeknum+monthnum;i++)
              {
                //showDays[i].setText(""+n);
             ite = new HashMap<String, Object>();
                ite.put("textItem", n+"");
                n++; 
                sDay.add(ite);
                
        }
    }