[英]Is it bad to change collection view cell with property observer?
class SceneCell: UICollectionViewCell {
override var isSelected: Bool {
didSet {
setSelected(bool: isSelected)
}
}
override var isHighlighted: Bool {
didSet {
setHighlighted(bool: isHighlighted)
}
}
@IBOutlet weak var thumbnailImageView: UIImageView!
override func draw(_ rect: CGRect) {
super.draw(rect)
self.backgroundColor = .clear
self.thumbnailImageView.layer.borderColor = UIColor.green.cgColor
self.thumbnailImageView.layer.masksToBounds = true
self.thumbnailImageView.clipsToBounds = true
self.thumbnailImageView.layer.cornerRadius = 8
}
func update(with scene: Scene) {
}
private func setHighlighted(bool: Bool) {
if bool {
self.alpha = 0.5
} else {
self.alpha = 1.0
}
}
private func setSelected(bool: Bool) {
if bool {
self.thumbnailImageView.layer.borderWidth = 2.5
} else {
self.thumbnailImageView.layer.borderWidth = 0
}
}
}
在我的代碼中,將isSelected設置為true時,我將圖像視圖的圖層邊框寬度更改為2.5。
當我選擇一個單元格並滾動收集視圖時,我認為重用該選定單元格時該單元格仍處於選定狀態,但是重用單元格變為未選定狀態。 其次,當我返回到所選單元格並重新使用未選中的單元格時,我認為它處於未選中狀態。 但是單元格會自動設置為選中狀態。
收集視圖是否自動管理這些內容?
問題的代碼運行正常。 這是記錄單元格選擇並為選定/取消選定狀態應用設置的替代解決方案。
class ViewController: UIViewController,UICollectionViewDelegate,UICollectionViewDataSource {
//......
var selectedIndexPaths = [IndexPath]()
public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedIndexPaths.append(indexPath)
}
public func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
if let index = selectedIndexPaths.index(of: indexPath) {
selectedIndexPaths.remove(at: index)
}
}
public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
//...
cell.setSelected(selectedIndexPaths.contains(indexPath)) //Remember to make the cell's setSelected() public.
//...
}
//......
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.