Question

我在尝试向集合视图添加标头时遇到问题。这是代码的相关部分：

collectionView?.register(ProfileHeaderView.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: Identifier.header)

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize{
    return CGSize(width: view.frame.width, height: 262.5)
}

override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
    if member == nil {
        return UICollectionReusableView()
    }
    switch kind {
    case UICollectionElementKindSectionHeader:
        let profileHeaderView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: Identifier.header, for: indexPath) as! ProfileHeaderView
        if indexPath.section == Section.header {
            profileHeaderView.config(...)
            return profileHeaderView
        } else {

            let reusabelView = UICollectionReusableView()
            let seperatorLine = UIView.seperatorLine()

            reusabelView.addSubview(seperatorLine)
            seperatorLine.bottomAnchor.constraint(equalTo: reusabelView.bottomAnchor).isActive = true
            seperatorLine.leftAnchor.constraint(equalTo: reusabelView.leftAnchor).isActive = true
            seperatorLine.centerXAnchor.constraint(equalTo: reusabelView.centerXAnchor).isActive = true

            reusabelView.backgroundColor = Color.white
            return reusabelView
        }
    default:
        return UICollectionReusableView()
    }
}

ProfileHeaderView是UICollectionReusableView的子类。运行此代码并尝试查看它的外观后，我收到此错误：

从-collectionView：viewForSupplementaryElementOfKind返回的视图：atIndexPath（UICollectionElementKindSectionHeader，{length = 2，path = 0 - 0}）未通过调用-dequeueReusableSupplementaryViewOfKind：withReuseIdentifier：forIndexPath：或者是nil（＆gt;）来检索（空）

Answer 1

我觉得你的情况有问题。

告知您收到的消息，告知您没有从collectionView中将您的补充视图出列。问题在于func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView返回创建（inited）视图的部分。

集合视图中的所有视图都必须从中出列。您可以在documentation中阅读更多内容。

尝试为UICollectionView Swift添加标头时出错

1 个答案: