【发布时间】：2017-05-19 22:29:52
【问题描述】：
我被这个奇怪的问题困扰了一段时间，似乎无法弄清楚。
设置
-
A 是
UICollectionView -
B是A的
UICollectionViewCells -
C 是一个
UICollectionView，当用户在 B 中点击时作为 B 的子视图添加+------------------------------+ |A | | | | +----------+ +----------+ | | |B | |B | | | |----------| | | | | | | | | | | |C | | | | | +----------+ +----------+ | +------------------------------+
问题
当初始化 C 的 UICollectionViewFlowLayout 滚动方向属性为 .horizontal，滚动经过第二个单元格，C 的单元格消失了。
作为奖励C 本身从 UI 中消失了：用户再次能够点击单元格，该单元格执行所有在 C 的通常移除时完成的操作。当再次点击以正常重新显示它时，触发了在 C 的显示上触发的操作，但 C 仍然在视觉上无处可寻。
当滚动方向设置为.vertical时不会出现此问题。
有没有人遇到过类似的问题或任何关于这里发生了什么的线索？
提前致谢。
编辑实际实施
(B)
import UIKit
class CollectionViewCell: UICollectionViewCell {
//...
private let cellId = "cellId"
private lazy var label: UILabel = {
return CollectionViewCell._label()
}()
fileprivate lazy var gallery: UICollectionView = {
return CollectionViewCell._gallery()
}()
//...
override init(frame: CGRect) {
super.init(frame: frame)
isOpaque = true
clipsToBounds = true
layer.borderWidth = 1.5
layer.cornerRadius = 8
// ...
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
private func onSwitchDisplayGallery(_ isDiplaying: Bool) {
switch isDiplaying {
case true:
addSubview(label)
label.topAnchor.constraint(equalTo: topAnchor).isActive = true
label.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
label.widthAnchor.constraint(equalTo: widthAnchor).isActive = true
label.heightAnchor.constraint(equalToConstant: frame.height / 5.25).isActive = true
gallery.register(NestedCollectionViewCell.self, forCellWithReuseIdentifier: cellId)
gallery.delegate = self
addSubview(gallery)
gallery.topAnchor.constraint(equalTo: label.bottomAnchor).isActive = true
gallery.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
gallery.widthAnchor.constraint(equalTo: widthAnchor).isActive = true
gallery.heightAnchor.constraint(equalTo: heightAnchor, constant: -frame.height / 5.25).isActive = true
case false:
print("removed cv")
// ...
}
}
//...
}
extension CollectionViewCell: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return gallery.frame.size
}
}
private extension CollectionViewCell {
class func _gallery() -> UICollectionView {
let layout = UICollectionViewFlowLayout()
layout.minimumInteritemSpacing = 0
layout.minimumLineSpacing = 0
layout.scrollDirection = .horizontal
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.isPagingEnabled = true
cv.showsHorizontalScrollIndicator = false
cv.translatesAutoresizingMaskIntoConstraints = false
return cv
}
class func _label() -> UILabel {
let label = UILabel()
label.font = UIFont(name: "Montserrat-Regular", size: 15)
label.textColor = .white
label.translatesAutoresizingMaskIntoConstraints = false
return label
}
}
(C)
import UIKit
class NestedCollectionViewCell: UICollectionViewCell {
private let containerView = NestedCollectionViewCell._containerView()
override init(frame: CGRect) {
super.init(frame: frame)
isOpaque = true
clipsToBounds = true
backgroundColor = .white
addSubview(containerView)
containerView.centerXAnchor.constraint(equalTo: centerXAnchor).isActive = true
containerView.centerYAnchor.constraint(equalTo: centerYAnchor).isActive = true
containerView.widthAnchor.constraint(equalTo: widthAnchor).isActive = true
containerView.heightAnchor.constraint(equalTo: heightAnchor).isActive = true
//...
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
private extension NestedCollectionViewCell {
class func _containerView() -> UIImageView {
let view = UIImageView()
view.contentMode = .scaleAspectFill
view.translatesAutoresizingMaskIntoConstraints = false
return view
}
}
编辑 2 我试过尼克的回答here。
当滚动方向设置为.vertical时，一切正常。
当设置为.horizontalC 时不显示单元格...
【问题讨论】：
-
你能显示你的代码吗？你在用锚吗？还是你使用了故事板？
-
@kbunarjo：一切都是通过锚点以编程方式完成的，是的。请参阅编辑后的答案和实施。
标签： ios swift uicollectionview autolayout uikit