日期处理一之NSLalendar的使用

一、日期和时间模式

 日期和时间格式由日期和时间模式字符串组成，在日期和时间模式字符串中未加引号的'A'到‘Z’和'a'到‘z’被解释为模式字母，用来表示日期或时间。字符串元素，文本可以使用单引号（‘’）引起来使用。定义以下模式字母(所有其他字符‘A’到‘Z’,'a'到‘z’都被保留)    

二、日期格式化

  1、  yyyy-MM-dd HH:mm:ss     2014-12-12 12:12:122、  yyyy/MM/dd HH:mm:ss     2014/12/12 12:12:12

三、思维导图

四、事例代码

xzr_formatter  是自定义的静态formatter类
//是今年
- (BOOL)xzr_isToYear{NSCalendar *calendar = [NSCalendar xzr_calendar];NSCalendarUnit unit = NSCalendarUnitYear;NSDateComponents *selfComponents = [calendar components:unit fromDate:计算的日期];NSDateComponents *nowComponents = [calendar components:unit fromDate:[NSDate date]];//年都一样return (selfComponents.year == nowComponents.year);
}
//是今天
- (BOOL)xzr_isToday{NSCalendar *calendar = [NSCalendar xzr_calendar];  // 自定义方法获取日历类对象NSCalendarUnit unit = NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay; //计算的日期，如年，月，日NSDateComponents *selfComponents = [calendar components:unit fromDate:计算的日期]; NSDateComponents *nowComponents = [calendar components:unit fromDate:[NSDate date]];//现在日期return (selfComponents.year == nowComponents.year && selfComponents.month == nowComponents.month && selfComponents.day == nowComponents.day);
}
//判断日期处理
+ (NSString *)xzr_dateString:(NSString *)string{//日期格式xzr_formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";NSDate *createDate = [xzr_formatter dateFromString:string] ;if (createDate.xzr_isToYear) {//是今年if (createDate.xzr_isToday) {//今天NSDate *nowDate = [NSDate date];NSCalendarUnit unit = NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay|NSCalendarUnitHour|NSCalendarUnitMinute|NSCalendarUnitSecond;NSDateComponents *components = [xzr_calendar components:unit fromDate:createDate toDate:nowDate options:NSCalendarWrapComponents ];if (components.hour >= 1) {//几小时前return [NSString stringWithFormat:@"%ld小时前",components.hour];}else if (components.minute >=1){//几分钟前return [NSString stringWithFormat:@"%ld分钟前",components.minute];}else{//刚刚return @"刚刚";}}else if (createDate.xzr_isToYestoday){//昨天xzr_formatter.dateFormat = @"昨天 HH:mm:ss";return [xzr_formatter stringFromDate:createDate];}else{xzr_formatter.dateFormat = @"MM-dd HH:mm:ss";return [xzr_formatter stringFromDate:createDate];}}else{ return string;}
}