第一种方法：

 [array sortUsingSelector:@selector(compareNsdate)]

- (NSComparisonResult)compareNsdate
{
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"yyyy-MM-dd"];

    NSMutableArray *tempArray = [NSMutableArray array];
    for (NSString *dateString in dateArray) {
        NSDate *date = [formatter dateFromString:dateString];
        [tempArray addObject:date];
    }
[tempArray sortUsingComparator:^NSComparisonResult(NSDate *date1, NSDate *date2) {
      
        return [date2 compare:date1];
    }];
}

第二种方法：

NSSortDescriptor *descriptor = [[NSSortDescriptor alloc] initWithKey:@"self"
                                                                   ascending:NO];
        NSArray *descriptors = [NSArray arrayWithObject:descriptor];
        NSArray *reverseOrder = [DateArr sortedArrayUsingDescriptors:descriptors];