CollectionView Header的使用

雨点打透心脏的1/2处 2022-06-03 09:50 120阅读 0赞

collectionView的使用和tableView类似，遵守数据源和代理方法是必要的，而不太常用的是 CollectionView Header，如果你想给每一组section设置不同的cell也是也可行的

遵守下面的代理方法：

- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
    {
        
        if (indexPath.section == 0) {
            if (self.attentionDataArr.count == 0) {
                PlaceholderView *placeHeader = (PlaceholderView *)[collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:PlaceheaderIdentifier forIndexPath:indexPath];
                if (self.hasAttentionPeople == 1) {
                    placeHeader.placeholdLabel.text = NSLocalizedString(@"HOME_ATTATENT_PLACEHOLDER_NULLLIVE_TIP", nil);
                }else if (self.hasAttentionPeople == 2) {
                    placeHeader.placeholdLabel.text = NSLocalizedString(@"HOME_ATTATENT_PLACEHOLDER_NULLFOLLOW_TIP", nil);
                }
                return placeHeader;
            }else{
                return nil;
            }
        }else{
            AttenttionCellHeaderView *attentionHeaderView  = (AttenttionCellHeaderView*)[collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headerIdentifier forIndexPath:indexPath];
            return attentionHeaderView;
        }
        
    }

每个headerView的高度，用以下方法返回

//这个方法是返回 Header的大小 size

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
    {
    
            if (section == 0) {
                if (self.attentionDataArr.count == 0) {
                    return CGSizeMake(kScreenWidth, 429 * ScreenHeightRatio);
                }
                return CGSizeZero;
            }else{
                return CGSizeMake(kScreenWidth, self.headerH);
            }
        
    }

就可以了，使用什么headerView记得要事先注册

[self.myCollectionView registerClass:[AttenttionCellHeaderView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:headerIdentifier]; 
    
    
    [self.myCollectionView registerClass:[PlaceholderView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:PlaceheaderIdentifier];

footer和header用法是一样的。