我有两种不同的单元格类型，一种用于评论，另一种用于回复。我正在尝试以相同的方式呈现它们collectionView然后也许可以像这样对它们进行分组：每个具有特定 id 的评论下面都有其回复。然而，无论什么尝试，我都失败了。
你会怎样做呢？
private var comments = [Comment]()
private var replies = [Reply]()
var items: [Any] = []
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return items.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// let item = items[indexPath.item]
var item = items[indexPath.item]
if item is Comment.Type {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: CommentCell.cellId, for: indexPath) as! CommentCell
cell.comment = items[indexPath.item] as? Comment
print(item)
return cell
} else {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: RepliesCell.cellId, for: indexPath) as! RepliesCell
cell.reply = items[indexPath.item] as? Reply
return cell
}
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let item = items[indexPath.item]
if item is CommentCell.Type {
let dummyCell = CommentCell(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: 50))
dummyCell.comment = items[indexPath.item] as? Comment
dummyCell.layoutIfNeeded()
let targetSize = CGSize(width: view.frame.width, height: 250)
let estimatedSize = dummyCell.systemLayoutSizeFitting(targetSize)
let height = max(40 + 8 + 8, estimatedSize.height)
return CGSize(width: view.frame.width, height: height)
} else {
let dummyCell = RepliesCell(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: 50))
dummyCell.reply = items[indexPath.item] as? Reply
dummyCell.layoutIfNeeded()
let targetSize = CGSize(width: view.frame.width, height: 250)
let estimatedSize = dummyCell.systemLayoutSizeFitting(targetSize)
let height = max(40 + 8 + 8, estimatedSize.height)
return CGSize(width: view.frame.width, height: height)
}
}
}
最佳实践解决方案
创建包含 Replies 对象列表的 Reply 模型和 Comment 模型
class Comment {
var commentId: Int
var commentText: String
var replies: [Reply]
init(commentId: Int, commentText: String, replies: [Reply]) {
self.commentId = commentId
self.commentText = commentText
self.replies = replies
}
}
class Reply {
var replyId: Int
var replyText: String
init(replyId: Int, replyText: String) {
self.replyId = replyId
self.replyText = replyText
}
}
为评论标题创建 UICollectionReusableView
class CommentHeader: UICollectionReusableView {
@IBOutlet weak var commentTextLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
func configure(with comment: Comment) {
commentTextLabel.text = comment.commentText
}
}
创建一个 UICollectionViewCell 用于回复
class ReplyCell: UICollectionViewCell {
@IBOutlet weak var replyTextLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
func configure(with reply: Reply) {
replyTextLabel.text = reply.replyText
}
}
创建一个 CommentsViewController 类，其中包含 UICollectionView 和评论数据列表
注意 header 和 cell 是在 viewDidLoad 方法中注册到集合视图中的
class CommentsViewController: UIViewController {
@IBOutlet weak var collectionView: UICollectionView!
var comments: [Comment] = [Comment]()
override func viewDidLoad() {
super.viewDidLoad()
collectionView.register(UINib(nibName: "CommentHeader", bundle: nil), forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "CommentHeaderIdentifier")
collectionView.register(UINib(nibName: "ReplyCell", bundle: nil), forCellWithReuseIdentifier: "ReplyCellIdentifier")
comments = getDummyComments(with: 3)
}
func getDummyComments(with count: Int) -> [Comment] {
var comments = [Comment]()
for i in 1...count {
comments.append(Comment(commentId: i, commentText: "Comment \(i)", replies: getDummyReplies(with: i)))
}
return comments
}
func getDummyReplies(with count: Int) -> [Reply] {
var replies = [Reply]()
for i in 1...count {
replies.append(Reply(replyId: i, replyText: "Reply \(i)"))
}
return replies
}
}
最后设置 UICollectionView 数据源和委托方法
extension CommentsViewController: UICollectionViewDataSource {
// for cell
func numberOfSections(in collectionView: UICollectionView) -> Int {
return comments.count
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return comments[section].replies.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let replyCell = collectionView.dequeueReusableCell(withReuseIdentifier: "ReplyCellIdentifier", for: indexPath) as! ReplyCell
replyCell.configure(with: comments[indexPath.section].replies[indexPath.row])
return replyCell
}
// for header
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
if kind == UICollectionElementKindSectionHeader {
let commentHeader = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: "CommentHeaderIdentifier", for: indexPath) as! CommentHeader
commentHeader.configure(with: comments[indexPath.section])
return commentHeader
}
return UICollectionReusableView()
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
return CGSize(width: collectionView.frame.width, height: 100) // this height is used for the example, you can use self sizing for height
}
}
extension CommentsViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: collectionView.frame.width, height: 100) // this height is used for the example, you can use self sizing for height
}
}
让我们看看评论屏幕:)
