[英]Swift - CollectionView Add Single Cell With Custom Animation
我有一個內部帶有CollectionView的UIViewController,以及一個僅向CollectionView的末尾添加新單元格的按鈕。 我通過使用它添加它:
func addNewFolderCell {
self.folder!.childFolders!.append(folder)
let count = self.folder!.childFolders!.count
let index = count > 0 ? count - 1 : count
let indexPath = IndexPath(item: index, section: 0)
collectionView?.performBatchUpdates({
collectionView!.insertItems(at: [indexPath])
})
}
可行,但是我想自定義默認動畫,以便在添加單元格時可以執行縮放和淡入。 IE:
UIView.animate(withDuration: 1.4, delay: 0.15 * Double(indexPath.row), animations: {
cell.alpha = 1.0
cell.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)
})
我找到了本教程,但是當您使用UIViewController而不是UICollectionViewController時,我無法弄清楚如何使其工作:
https://littlebitesofcocoa.com/306-customizing-collection-view-cell-insertion-animations
您將動畫放在collectionView:willDisplayCell:forItemAtIndexPath中:
extension ViewController: UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
cell.alpha = 0
cell.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)
UIView.animate(withDuration: 0.25) {
cell.alpha = 1
cell.transform = .identity
}
}
}
編輯更新:
假設你使用UICollectionViewFlowLayout你需要它的子類,並覆蓋initialLayoutAttributesForAppearingSupplementaryElement(ofKind:在:)它定義UICollectionViewLayout ,UICollectionViewFlowLayout的抽象父。 如果從此方法返回屬性,它們將用作單元的初始屬性,並且動畫系統會將其插值為其最終值。 然后,將自定義UICollectionViewFlowLayout的實例設置為集合視圖的.collectionViewLayout
編輯添加代碼:
class MyFlowLayout: UICollectionViewFlowLayout {
override func initialLayoutAttributesForAppearingItem(at itemIndexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
let attributes = UICollectionViewLayoutAttributes()
attributes.alpha = 0
attributes.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)
return attributes
}
}
class ViewController: UIViewController {
var collectionView: UICollectionView!
override func viewDidLoad() {
collectionView.collectionViewLayout = MyFlowLayout()
}
}
請嘗試嘗試此答案,並告訴我它是否對您有用。
不要忘記調用UICollectionViewDelegateFlowLayout
var insertingIndexPaths = [IndexPath]()
func layoutAttributesForItem(at indexPath: IndexPath) -> UICollectionViewLayoutAttributes? {
let attributes = "YourCollectionview".layoutAttributesForItem(at: indexPath)
if insertingIndexPaths.contains(indexPath) {
attributes?.alpha = 1.0
attributes?.transform = CGAffineTransform(
scaleX: 0.1,
y: 0.1
)
}
return attributes
}
//這里是您的按鈕單擊以插入新項目
@IBAction func btn_click_sign_in(_ sender: Any) {
//here you have insert one item into your array
// for Exa. My array count is 3 here.
// So I am adding new object array.append(element)
let indexPath = IndexPath(
item: **yourArray count** - 1,
section: 0
)
"YourCollectionview"?.performBatchUpdates({
self.coll_pagview?.insertItems(at: [indexPath])
}, completion: nil)
}
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