ios - 如何在选择 Swift 3.0 时缩放 UICollectionViewCell？

Question

我在这里尝试突出显示选择的 UICollectionViewCell，如图所示。我尝试将边框添加到所选单元格，并且边框位于单元格内容 View 内。这是我的尝试:

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let cell = priorityCollectionView.cellForItem(at: indexPath)  as? BCPriorityListCollectionViewCell
    let borderWidth: CGFloat = 6
    cell?.contentView.frame = (cell?.labelBackground.frame.insetBy(dx: +borderWidth, dy: +borderWidth))!
    cell?.contentView.layer.borderColor = cell?.backgroundColor?.cgColor
    cell?.contentView.layer.borderWidth = borderWidth
}

func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
    let cell = priorityCollectionView.cellForItem(at: indexPath)  as? BCPriorityListCollectionViewCell
    let borderWidth: CGFloat = 0
    cell?.contentView.frame = (cell?.labelBackground.frame.insetBy(dx: +borderWidth, dy: +borderWidth))!
    cell?.contentView.layer.borderColor = UIColor.clear.cgColor
    cell?.contentView.layer.borderWidth = borderWidth

}

如何做到这一点？

Answer 1

不是为所选单元格添加边框宽度，而是使用变换比例缩放所选单元格。在 didSelect 中写入这段代码:

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    let selectedCell = priorityCollectionView.cellForItem(at: indexPath)  as? BCPriorityListCollectionViewCell
    priorityCollectionView.bringSubview(toFront: selectedCell!)

    UIView.animate(withDuration: 0.2, delay: 0, usingSpringWithDamping: 5, initialSpringVelocity: 0, options: [], animations: { 
        selectedCell?.transform = CGAffineTransform(scaleX: 1.2, y: 2)
        })  
}

在 didDeselect 中:

func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
    let unselectedCell = priorityCollectionView.cellForItem(at: indexPath)  as? BCPriorityListCollectionViewCell
    UIView.animate(withDuration: 0.2, delay: 0, usingSpringWithDamping: 5, initialSpringVelocity: 0, options: [], animations: {
        unselectedCell?.transform = .identity
    })
}

结果: