我正在尝试为UICollectionView添加一个头部。我使用的是自定义布局,可以横向滚动,用于查看朋友列表中的头像图像。我可以让头部出现,但无法重用。一旦头部视图离开屏幕,它就永远不会重新加载。有人能想出原因吗?
谢谢!
集合视图数据源:
- (UICollectionReusableView *)collectionView:(SWAvatarViewerCollectionView *)collectionView
viewForSupplementaryElementOfKind:(NSString *)kind
atIndexPath:(NSIndexPath *)indexPath
{
if (self.showAddAvatarHeaderView && [kind isEqualToString:UICollectionElementKindSectionHeader]) {
return [collectionView dequeueAddAvatarViewHeaderForIndexPath:indexPath];
}
return nil;
}
- (CGSize)collectionView:(UICollectionView *)collectionView
layout:(SWAvatarViewerCollectionViewFlowLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
{
if (!self.showAddAvatarHeaderView) {
return CGSizeZero;
}
return CGSizeMake(kSWAvatarViewerAddAvatarHeaderViewWidth, CGRectGetHeight(collectionView.bounds));
}
头像集合视图:
- (SWAvatarViewerAddAvatarHeaderView *)dequeueAddAvatarViewHeaderForIndexPath:(NSIndexPath *)indexPath {
SWAvatarViewerAddAvatarHeaderView *headerView = [super dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader
withReuseIdentifier:[SWAvatarViewerAddAvatarHeaderView headerReuseIdentifier]
forIndexPath:indexPath];
headerView.delegate = self;
return headerView;
}
Nib文件注册:
[self registerNib:[SWAvatarViewerAddAvatarHeaderView nib]
forSupplementaryViewOfKind:UICollectionElementKindSectionHeader
withReuseIdentifier:[SWAvatarViewerAddAvatarHeaderView headerReuseIdentifier]];
布局:
#pragma mark - Initialization
- (void)configureFlowLayout {
self.scrollDirection = UICollectionViewScrollDirectionHorizontal;
// Padding for cells is taken into account in the cell's layout. Remove all
// padding between cells
self.sectionInset = UIEdgeInsetsMake(0, 00.0f, 0, 00.0f);
self.minimumLineSpacing = 0.0f;
self.minimumInteritemSpacing = CGFLOAT_MAX;
_cellBottomLabelFont = [UIFont systemFontOfSize:12.0];
CGSize defaultAvatarSize = CGSizeMake(44.0f, 44.0f);
_avatarViewSize = defaultAvatarSize;
_springinessEnabled = YES;
_springResistanceFactor = 1000;
}