iOS常用公共方法

/**

 *  计算上次日期距离现在多久

 *

 *  @param lastTime    上次日期(需要和格式对应)

 *  @param format1     上次日期格式

 *  @param currentTime 最近日期(需要和格式对应)

 *  @param format2     最近日期格式

 *

 *  @return xx分钟前、xx小时前、xx天前

 */

+ (NSString *)timeIntervalFromLastTime:(NSString *)lastTime

                        lastTimeFormat:(NSString *)format1

                         ToCurrentTime:(NSString *)currentTime

                     currentTimeFormat:(NSString *)format2{

    //上次时间

    NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc]init];

    dateFormatter1.dateFormat = format1;

    NSDate *lastDate = [dateFormatter1 dateFromString:lastTime];

    //当前时间

    NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc]init];

    dateFormatter2.dateFormat = format2;

    NSDate *currentDate = [dateFormatter2 dateFromString:currentTime];

    return [Utilities timeIntervalFromLastTime:lastDate ToCurrentTime:currentDate];

}

+ (NSString *)timeIntervalFromLastTime:(NSDate *)lastTime ToCurrentTime:(NSDate *)currentTime{

    NSTimeZone *timeZone = [NSTimeZone systemTimeZone];

    //上次时间

    NSDate *lastDate = [lastTime dateByAddingTimeInterval:[timeZone secondsFromGMTForDate:lastTime]];

    //当前时间

    NSDate *currentDate = [currentTime dateByAddingTimeInterval:[timeZone secondsFromGMTForDate:currentTime]];

    //时间间隔

    NSInteger intevalTime = [currentDate timeIntervalSinceReferenceDate] - [lastDate timeIntervalSinceReferenceDate];

    //秒、分、小时、天、月、年

    NSInteger minutes = intevalTime / 60;

    NSInteger hours = intevalTime / 60 / 60;

    NSInteger day = intevalTime / 60 / 60 / 24;

    NSInteger month = intevalTime / 60 / 60 / 24 / 30;

    NSInteger yers = intevalTime / 60 / 60 / 24 / 365;

    if (minutes <= 10) {

        return  @"刚刚";

    }else if (minutes < 60){

        return [NSString stringWithFormat: @"%ld分钟前",(long)minutes];

    }else if (hours < 24){

        return [NSString stringWithFormat: @"%ld小时前",(long)hours];

    }else if (day < 30){

        return [NSString stringWithFormat: @"%ld天前",(long)day];

    }else if (month < 12){

        NSDateFormatter * df =[[NSDateFormatter alloc]init];

        df.dateFormat = @"M月d日";

        NSString * time = [df stringFromDate:lastDate];

        return time;

    }else if (yers >= 1){

        NSDateFormatter * df =[[NSDateFormatter alloc]init];

        df.dateFormat = @"yyyy年M月d日";

        NSString * time = [df stringFromDate:lastDate];

        return time;

    }

    return @"";

}