Add date to Events.EXDATE Android calendar provider?

Question

I want to add exception date Events.EXDATE but I but I add it but it no effect. I also read here android: EXDATE format when adding a calendar event

I also make a test by make a daily event and delete one of them , Finally i get data in Events.EXDATE column but it 's alway null.

Update : I can add exDate now but Android may be allow us to add one day only, I want to add more than a day,

Does anybody do it before? Thank for your reading

            ContentValues values = new ContentValues();


        values.put(Events.EVENT_TIMEZONE, "Asia/Seoul");
        if(calendar_Id!=-1){

            values.put(Events.CALENDAR_ID, calendar_Id);
        }
        for(String exDate : event.getExDatesList()){
            values.put(Events.EXDATE, exDate);
        }
        if(!username.equals("")){
            values.put(Events.ORGANIZER, username);
        }
        if(event.getSummarry()!=null){
            values.put(Events.TITLE, event.getSummarry());
        }
        if(event.getDescription()!=null){
            values.put(Events.DESCRIPTION, event.getDescription());
        }
        if(event.getDateStart()!=null){
            values.put(Events.DTSTART, CaldavGlobalVar.convertTIMEtomilisecond(event.getDateStart(), event.getAllDay()));

        }
        if(event.getDateEnd()!=null){
            values.put(Events.DTEND, CaldavGlobalVar.convertTIMEtomilisecond(event.getDateEnd(), event.getAllDay()));
        }

        if(event.getLocation()!=null&&!event.getLocation().equals("")){
            values.put(Events.EVENT_LOCATION, event.getLocation());
        }

        values.put(Events.ALL_DAY, event.getAllDay());