iOS规范化时间格式，object-C计算指定时间与当前的时间差

#import <Foundation/Foundation.h>

@interface LuDate : NSDate
+(NSString *) compareCurrentTime:(NSString*) strDate;
@end

/**

* 计算指定时间与当前的时间差

* @param compareDate   某一指定时间

* @return 多少(秒or分or天or月or年)+前 (比如，3天前、10分钟前)

*/

+(NSString *) compareCurrentTime:(NSString*) strDate

{

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

[dateFormatter setDateFormat: @"yyyy-MM-dd HH:mm:ss"];

NSDate *compareDate= [dateFormatter dateFromString:strDate];

NSTimeInterval  timeInterval = [compareDate timeIntervalSinceNow];

timeInterval = -timeInterval;

long temp = 0;

NSString *result;

if (timeInterval < 60) {

result = [NSString stringWithFormat:@"刚刚"];

}

else if((temp = timeInterval/60) <60){

result = [NSString stringWithFormat:@"%ld分前",temp];

}

else if((temp = temp/60) <24){

result = [NSString stringWithFormat:@"%ld小前",temp];

}

else if((temp = temp/24) <30){

result = [NSString stringWithFormat:@"%ld天前",temp];

}

else if((temp = temp/30) <12){

result = [NSString stringWithFormat:@"%ld月前",temp];

}

else{

temp = temp/12;

result = [NSString stringWithFormat:@"%ld年前",temp];

}

return  result;

}
@end