Calendar 显示是否是 今天 本周 本月 本年 （应用于微信 QQ 显示历史聊天列表 时间显示）

/**
* 是否是昨天
*
* @param time
* @return
*/
public static boolean isYesterday(long time) {
Calendar cal = Calendar.getInstance();
int d = cal.get(Calendar.DAY_OF_MONTH);
int dy = cal.get(Calendar.YEAR);
cal.setTimeInMillis(time);
int i = cal.get(Calendar.DAY_OF_MONTH);
int iy = cal.get(Calendar.YEAR);
if (d == 1) {
cal.set(Calendar.DAY_OF_MONTH, 0);
d = cal.get(Calendar.DAY_OF_MONTH);
return d == i && dy == iy;
}
return d - 1 == i && dy == iy;
}

/**
* 得到本周周一
*
*/
public static long getMondayOfThisWeek() {
Calendar c = Calendar.getInstance();
int day_of_week = c.get(Calendar.DAY_OF_WEEK) - 1;
if (day_of_week == 0)
day_of_week = 7;
c.add(Calendar.DATE, -day_of_week + 1);
return c.getTimeInMillis();
}

/**
* 得到本周周日
*
*/
public static long getSundayOfThisWeek() {
Calendar c = Calendar.getInstance();
int day_of_week = c.get(Calendar.DAY_OF_WEEK) - 1;
if (day_of_week == 0)
day_of_week = 7;
c.add(Calendar.DATE, -day_of_week + 7);
return c.getTimeInMillis();
}

/**
* 是否是这个星期
*
* @param time
* @return
*/
public static boolean isWeek(long time) {
long startWeek = getMondayOfThisWeek(); // 本周一
long endWeek = getSundayOfThisWeek();
return time >= startWeek && time <= endWeek;
}

/**
* 显示星期格式
*
* @param time
* @return
*/
public static String showWeekString(long time) {
Calendar calendar = Calendar.getInstance();
calendar.setTimeInMillis(time);
if (Calendar.MONDAY == calendar.get(Calendar.DAY_OF_WEEK)) {
return "星期一";
}
if (Calendar.TUESDAY == calendar.get(Calendar.DAY_OF_WEEK)) {
return "星期二";
}
if (Calendar.WEDNESDAY == calendar.get(Calendar.DAY_OF_WEEK)) {
return "星期三";
}
if (Calendar.THURSDAY == calendar.get(Calendar.DAY_OF_WEEK)) {
return "星期四";
}
if (Calendar.FRIDAY == calendar.get(Calendar.DAY_OF_WEEK)) {
return "星期五";
}
if (Calendar.SATURDAY == calendar.get(Calendar.DAY_OF_WEEK)) {
return "星期六";
}
if (Calendar.SUNDAY == calendar.get(Calendar.DAY_OF_WEEK)) {
return "星期日";
}
return "星期一";
}

/**
* 是否是今年
*
* @param time
* @return
*/
public static boolean isYear(long time) {
Calendar cal = Calendar.getInstance();
int dy = cal.get(Calendar.YEAR);
cal.setTimeInMillis(time);
int iy = cal.get(Calendar.YEAR);
return dy == iy;
}

/**
* 今天 昨天 本周 本年 更久 显示格式
*
* @param time
* @return
*/
public static String CastsendTime(long time) {
// 今天
if (isCurrentDay(time)) {
return long2String(time, FORMAT_DATE_HHMM);
}// 昨天
else if (isYesterday(time)) {
return FORMAT_DATE_YESTERDAY;
}// 这个星期
else if (isWeek(time)) {
return showWeekString(time);
} else if (isYear(time)) {
return long2String(time, FORMAT_DATE_MMDD);
} else {
return long2String(time, FORMAT_DATE_YYMMDD);
}
}