UICollectionView HeaderView 怎么做

在初始化时和添加cell类似
[collectionView registerClass:[HeadView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:HeadID];
再加楼上的

• (UICollectionReusableView )collectionView:(UICollectionView )collectionView viewForSupplementaryElementOfKind:(NSString )kind atIndexPath:(NSIndexPath )indexPath
  {

if ([kind isEqualToString:UICollectionElementKindSectionHeader]) {
HeadView * view = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:HeadID forIndexPath:indexPath];
return view;
}
return nil;
}