Android使用GridView实现日历的简单功能

简单的日历实现，只是显示了每一个月，没有显示当天和记事这些功能

主要是计算月初是周几，月末是周几，然后相应的显示上一月多少天和下一月多少天。

先看一下关于日期的用到的几个工具类

 /**
   * 获取该月天数
   */
  public static int getcurrentmonthday(long millsec) {
    calendar calendar = calendar.getinstance();
    calendar.settimeinmillis(millsec);
    calendar.set(calendar.date, 1);
    calendar.roll(calendar.date, -1);
    int datecount = calendar.get(calendar.date);
    return datecount;
  }

  /**
   * 获取当月第一天
   */
  public static long getfirofmonth(long millsec) {
    calendar calendar = calendar.getinstance();
    calendar.settimeinmillis(millsec);
    calendar.set(calendar.date, 1);
    return calendar.gettimeinmillis();
  }

  /**
   * 获取当前时间戳
   */
  public static long getcurrenttime() {
    calendar calendar = calendar.getinstance();
    return calendar.gettimeinmillis();
  }

  /**
   * 获取上一月/下一月
   */
  public static long getlastornextmonth(long millsec, int count) {
    calendar calendar = calendar.getinstance();
    calendar.settimeinmillis(millsec);
    calendar.add(calendar.month, count);
    return calendar.gettimeinmillis();
  }

  /**
   * 格式化到月份
   */
  public static string long2str(long millsec) {
    simpledateformat sdf = new simpledateformat("yyyy-mm");
    return sdf.format(new date(millsec));
  }

用一个list存放每一天，因为之前考虑到每一天有记事这些，所以封装了一个类，如果不需要的话可以直接一个时间戳就可以。
打开之后先获取当前的时间戳，然后初始化到当前月份的第一天，通过工具类中方法。
然后就是计算了，把上月结余的、本月所有、下月的一起添加到list中。

 private void setcalendarlist(long millsecs) {
    beans.clear();
    calendar calendar = calendar.getinstance();
    calendar.settimeinmillis(millsecs);
//    int nor = today.getday();
    int max = dateutil.getcurrentmonthday(millsecs);
    /**
     * 当月日历
     */
    for (int i = 1; i <= max; i++) {
      daybean bean = new daybean();
      calendar cc = calendar.getinstance();
      cc.settimeinmillis(millsecs);
      cc.add(calendar.day_of_month, i - 1);
      setbean(bean, cc);
      bean.setiscurrentmonth(true);
      beans.add(bean);
    }
    //上月结余
    int fir_day_of_week = beans.get(0).getcalendar().get(calendar.day_of_week);
    log.e("aaa", "week_last:" + fir_day_of_week);
    if (fir_day_of_week != 2) {
      if(fir_day_of_week == 1){
        for (int i = 0; i < 6; i++) {
          daybean bean = new daybean();
          calendar cc = calendar.getinstance();
          cc.settimeinmillis(millsecs);
          cc.add(calendar.day_of_month, -i -1);
          setbean(bean, cc);
          log.e("aaa", "last:" + bean.getday());
          bean.setiscurrentmonth(false);
          beans.add(0, bean);
        }
      }else{
        for (int i = 0; i < fir_day_of_week-2; i++) {
          daybean bean = new daybean();
          calendar cc = calendar.getinstance();
          cc.settimeinmillis(millsecs);
          cc.add(calendar.day_of_month, -i-1);
          setbean(bean, cc);
          log.e("aaa", "last:" + bean.getday());
          bean.setiscurrentmonth(false);
          beans.add(0, bean);
        }
      }

    }
    //下月
    int last_day_of_week = beans.get(beans.size() - 1).getcalendar().get(calendar.day_of_week);
    log.e("aaa", "week_next:" + last_day_of_week);
    if (last_day_of_week != 1) {
      for (int i = last_day_of_week; i < 8; i++) {
        daybean bean = new daybean();
        calendar cc = calendar.getinstance();
        cc.settimeinmillis(millsecs);
        cc.add(calendar.day_of_month, i - last_day_of_week);
        setbean(bean, cc);
        log.e("aaa", "next:" + bean.getday());
        bean.setiscurrentmonth(false);
        beans.add(bean);
      }
    }
    gridviewadapter adapter = new gridviewadapter(this, beans);
    mgridview.setadapter(adapter);
  }

  private void setbean(daybean bean, calendar cc) {
    bean.setcalendar(cc);
    bean.setday(cc.get(calendar.day_of_month));
  }

设置每一天时设置了一个字段为是否为本月，如果是，则设置为黑色，否则设为灰色显示，在adapter中的getview方法中设置即可。

  @override
  public view getview(int position, view convertview, viewgroup parent) {
    viewholder holder;
    if (convertview == null) {
      convertview = inflater.inflate(r.layout.item_layout, null);
      holder = new viewholder();
      holder.day_text = (textview) convertview.findviewbyid(r.id.day_text);
      convertview.settag(holder);
    } else {
      holder = (viewholder) convertview.gettag();
    }
    holder.day_text.settext(beans.get(position).getday() + "");
    if (beans.get(position).istoday()) {
      holder.day_text.setbackgroundcolor(color.red);
    } else {
      holder.day_text.setbackgroundcolor(color.white);
    }
    if (beans.get(position).iscurrentmonth()) {
      holder.day_text.settextcolor(color.black);
    } else {
      holder.day_text.settextcolor(color.gray);
    }

    return convertview;
  }

  class viewholder {
    textview day_text;
  }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。