[英]Swift, iOS15, UIKit, CollectionView header issue
我正在測試iOS15和UIKit的一些新功能。 我遇到了一些問題,不確定如何解決。 我沒有更改該代碼。 這只是一段與 iOS 14 完美配合的代碼,現在更新我的目標后,它會拋出錯誤。
Xcode 在為dataSource返回類型為UICollectionElementKindSectionHeader的UICollectionView的自定義 header時崩潰。 這是我的代碼:
private func configureDataSource() {
dataSource = UICollectionViewDiffableDataSource<Section, Follower>(collectionView: collectionView, cellProvider: { (collectionView, indexPath, followers) -> UICollectionViewCell? in
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: FollowerCell.reuseId, for: indexPath) as! FollowerCell
cell.set(on: followers)
return cell
})
dataSource.supplementaryViewProvider = { (collectionView, kind, indexPath) in
let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionView.elementKindSectionHeader,
withReuseIdentifier: FollowersCollectionHeaderView.reuseId,
for: indexPath) as! FollowersCollectionHeaderView
header.set(with: self.user)
return header
}
}
日志說:
從 -collectionView:viewForSupplementaryElementOfKind:atIndexPath: 返回的視圖與它所使用的元素種類不匹配。 當請求元素種類“FollowersCollectionHeaderView”的視圖時,數據源使為元素種類“UICollectionElementKindSectionHeader”注冊的視圖出隊。
我確實將UICollectionElementKindSectionHeader 轉換為FollowersCollectionHeaderView ,因此我不確定這里的問題是什么。
我看過WWDC21 what's new in UIKit但沒有看到任何提及該特定代碼的任何更改。
有什么建議,要在該代碼中修復什么?
這是我想出的部分解決方案。 Apple 建議使用對象的 ID 作為 collectionView 單元格的參考。
enum Section { case main }
var dataSource: UICollectionViewDiffableDataSource<Section, Follower.ID>!
// MARK: - Collection View configurations
fileprivate lazy var collectionView: UICollectionView = {
let collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: UIHelper.createCompositionalLayout())
collectionView.delegate = self
collectionView.backgroundColor = .systemBackground
collectionView.register(FollowersCollectionHeaderView.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: FollowersCollectionHeaderView.reuseId)
view.addSubview(collectionView)
return collectionView
}()
fileprivate lazy var snapshot: NSDiffableDataSourceSnapshot<Section, Follower.ID> = {
var snapshot = NSDiffableDataSourceSnapshot<Section, Follower.ID>()
snapshot.appendSections([.main])
let itemIdentifiers = followers.map { $0.id }
snapshot.appendItems(itemIdentifiers, toSection: .main)
dataSource.apply(snapshot, animatingDifferences: true)
return snapshot
}()
fileprivate func updateData(with followers: [Follower]) {
snapshot = NSDiffableDataSourceSnapshot<Section, Follower.ID>()
snapshot.appendSections([.main])
let itemIdentifiers = followers.map { $0.id }
snapshot.appendItems(itemIdentifiers, toSection: .main)
dataSource.apply(snapshot, animatingDifferences: true)
}
fileprivate func configureDataSource() {
let cellRegistration = UICollectionView.CellRegistration<FollowerCell, Follower.ID> { [weak self]
cell, indexPath, followerID in
guard let self = self else { return }
let followerArray = self.followers.filter { $0.id == followerID }
if let follower = followerArray.first {
cell.set(on: follower)
}
}
dataSource = UICollectionViewDiffableDataSource<Section, Follower.ID>(collectionView: collectionView) {
collectionView, indexPath, itemIdentifier in
return collectionView.dequeueConfiguredReusableCell(using: cellRegistration,
for: indexPath,
item: itemIdentifier)
}
let headerRegistration = createSectionHeaderRegistration()
dataSource.supplementaryViewProvider = { collectionView, elementKind, indexPath in
return collectionView.dequeueConfiguredReusableSupplementary(using: headerRegistration, for: indexPath)
}
}
fileprivate func createSectionHeaderRegistration() -> UICollectionView.SupplementaryRegistration<FollowersCollectionHeaderView> {
return UICollectionView.SupplementaryRegistration<FollowersCollectionHeaderView>(
elementKind: FollowersCollectionHeaderView.reuseId) { [weak self] supplementaryView, elementKind, indexPath in
guard let self = self else { return }
supplementaryView.set(with: self.user)
}
}
使用UICollectionView.elementKindSectionHeader
而不是您創建的字符串
override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
guard let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: "headerView", for: indexPath) as? TitleDetailsHeaderView else { return UICollectionReusableView() }
return header
}
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