扩展UICollectionViewCell on tap

Question

我有垂直向上滚动的UICollectionView，我想在点击中更改项目高度。在默认状态下，单元格高度为2/3屏幕高度。我尝试了以下几点：

override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath)
            if let cell = cell as? TutorialCell {
                let attribute = layout.layoutAttributesForItem(at: indexPath)
                attribute?.frame = CGRect.init(x: 0, y: 0, width: UIScreen.main.bounds.size.width,
                                               height: UIScreen.main.bounds.size.height)
                collectionView.reloadItems(at: [indexPath])

            }
        print(indexPath.row)
    }

但它不起作用。

Answer 1

您可以通过UICollectionViewDelegateFlowLayout方法sizeForItemAt实现这一点

声明一个变量

var selectIndex: Int = -1

在您的didSelectItemAt中添加以下内容

override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    self.selectIndex = indexPath.row

    collectionView.reloadData()
}

为UICollectionViewDelegateFlowLayout添加扩展

extension YourViewController: UICollectionViewDelegateFlowLayout {

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        let height = (self.selectIndex == indexPath.row ) ?
            UIScreen.main.bounds.size.height :
            (UIScreen.main.bounds.size.height * 2) / 3

        return CGSize(width:UIScreen.main.bounds.size.width, height:height)
    }
}