-(NSString*)getTimeWithDays:(NSInteger)add dis:(NSInteger)dis{    NSInteger days = 0;    if (add!=0) {        days=add;    }    if (dis!=0) {        days=-dis;    }    NSDateFormatter *formatter=[[NSDateFormatter alloc]init];    [formatter setDateFormat:@"yyyy-MM-dd"];    NSDate*nowDate=[NSDate date];    NSTimeInterval  oneDay = 24*60*60*1;    NSDate *theDate=[nowDate initWithTimeIntervalSinceNow:+oneDay*days];    NSString *dataTime=[formatter stringFromDate:theDate];        NSLog(@"%@",dataTime);    return dataTime;}

直接调用。。。就好了