日期处理一之NSLalendar的使用

一、日期和时间模式

?

1 2 3

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 2	1、  yyyy-MM-dd HH:mm:ss     2014-12-12 12:12:12 2、  yyyy/MM/dd HH:mm:ss     2014/12/12 12:12:12

三、思维导图

四、事例代码

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

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;       } }