iOS 之NSDate的Category

iOS 之NSDate的Category

判断日期是是否是今年？今天？

NSDate+Extension.h

#import <Foundation/Foundation.h>@interface NSDate (Extension)//比较from和self的时间差值- (NSDateComponents *)deltaFrom:(NSDate *)from; //是否为今年- (BOOL)isThisYear;//是否为今天- (BOOL)isToday;//是否为昨天- (BOOL)isYesterday;//是否为明天- (BOOL)isTomorrow;@end

NSDate+Extension.m

#import "NSDate+Extension.h"@implementation NSDate (Extension)- (NSDateComponents *)deltaFrom:(NSDate *)from{    // 日历    NSCalendar *calendar = [NSCalendar currentCalendar];    // 比较时间    NSCalendarUnit unit = NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;    return [calendar components:unit fromDate:from toDate:self options:0];}- (BOOL)isThisYear{    // 日历    NSCalendar *calendar = [NSCalendar currentCalendar];    NSInteger nowYear = [calendar component:NSCalendarUnitYear fromDate:[NSDate date]];    NSInteger selfYear = [calendar component:NSCalendarUnitYear fromDate:self];    return nowYear == selfYear;}- (BOOL)isToday{    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];    fmt.dateFormat = @"yyyy-MM-dd";    NSString *nowString = [fmt stringFromDate:[NSDate date]];    NSString *selfString = [fmt stringFromDate:self];    return [nowString isEqualToString:selfString];}- (BOOL)isYesterday{    // 2014-12-31 23:59:59 -> 2014-12-31    // 2015-01-01 00:00:01 -> 2015-01-01    // 日期格式化类    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];    fmt.dateFormat = @"yyyy-MM-dd";    NSDate *nowDate = [fmt dateFromString:[fmt stringFromDate:[NSDate date]]];    NSDate *selfDate = [fmt dateFromString:[fmt stringFromDate:self]];    NSCalendar *calendar = [NSCalendar currentCalendar];    NSDateComponents *cmps = [calendar components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:selfDate toDate:nowDate options:0];    return cmps.year == 0    && cmps.month == 0    && cmps.day == 1;}- (BOOL)isTomorrow{     NSDateFormatter *fmt = [[NSDateFormatter alloc] init];    fmt.dateFormat = @"yyyy-MM-dd";    NSDate *nowDate = [fmt dateFromString:[fmt stringFromDate:[NSDate date]]];    NSDate *selfDate = [fmt dateFromString:[fmt stringFromDate:self]];    NSCalendar *calendar = [NSCalendar currentCalendar];    NSDateComponents *cmps = [calendar components:NSCalendarUnitDay | NSCalendarUnitMonth | NSCalendarUnitYear fromDate:nowDate toDate:selfDate options:0];    return cmps.year == 0    && cmps.month == 0    && cmps.day == 1;}@end

简单使用TopicModel

#import “TopicModel.m”文件中

- (NSString *)create_time{    // 日期格式化类    NSDateFormatter *fmt = [[NSDateFormatter alloc] init];    // 设置日期格式(y:年,M:月,d:日,H:时,m:分,s:秒)    fmt.dateFormat = @"yyyy-MM-dd HH:mm:ss";    // 帖子的创建时间    NSDate *create = [fmt dateFromString:_create_time];    if (create.isThisYear) { // 今年        if (create.isToday) { // 今天            NSDateComponents *cmps = [[NSDate date] deltaFrom:create];            if (cmps.hour >= 1) { // 时间差距 >= 1小时                return [NSString stringWithFormat:@"%zd小时前", cmps.hour];            } else if (cmps.minute >= 1) { // 1小时 > 时间差距 >= 1分钟                return [NSString stringWithFormat:@"%zd分钟前", cmps.minute];            } else { // 1分钟 > 时间差距                return @"刚刚";            }        } else if (create.isYesterday) { // 昨天            fmt.dateFormat = @"昨天 HH:mm:ss";            return [fmt stringFromDate:create];        } else if(creat.isTomorrow){            fmt.dateFormat = @"明天 HH:mm:ss";            return [fmt stringFromDate:create];        }else { // 其他            fmt.dateFormat = @"MM-dd HH:mm:ss";            return [fmt stringFromDate:create];        }    } else { // 非今年        return _create_time;    }}