iOS --- 比较当前时间与特定时间的时间差..

系统时间与后台给的时间比较

- (NSString *) compareCurrentTime:(NSString *)str
{
    
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSDate *timeDate = [dateFormatter dateFromString:str];
    NSTimeInterval timeInterval = [[NSDate date] timeIntervalSinceDate:timeDate];
  
    long temp = 0;
    NSString *result;
    if (timeInterval < 60) {
        result = [NSString stringWithFormat:@"刚刚"];
    }
    else if((temp = timeInterval/60) <60){
        result = [NSString stringWithFormat:@"%ld分钟前",temp];
    }
    
    else if((temp = temp/60) <24){
        result = [NSString stringWithFormat:@"%ld小时前",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:@"%@",str];
    }
    return  result;
}