时间比较

-(int)compareOneDay:(NSString*)oneDay withAnotherDay:(NSString*)anotherDay

{

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

    [dateFormattersetDateFormat:@"yyyy-MM-dd"];

    NSDate*dateA = [dateFormatterdateFromString:oneDay];

    NSDate*dateB = [dateFormatterdateFromString:anotherDay];

    NSComparisonResultresult = [dateAcompare:dateB];

    if (result == NSOrderedDescending) {

       NSLog(@"oneDay比 anotherDay时间晚");

        return1;

    }

    elseif(result ==NSOrderedAscending){

        NSLog(@"oneDay比 anotherDay时间早");

        return-1;

    }

     NSLog(@"两者时间是同一个时间");

    return0;

}