我在表格 View 中有一个 collectionView，它工作得很好，但问题是 Collection View 单元格宽度在初始阶段不能完美地工作，但一旦滚动它就可以工作。

您可以在此处查看，在第一部分中，它显示了全名，但在其他部分中，它截断了尾部并且在滚动后有效。

这是重要的代码

class SubjectsViewFlowLayout: UICollectionViewFlowLayout {

override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
    let attributesForElementsInRect = super.layoutAttributesForElements(in: rect)
    var newAttributesForElementsInRect = [UICollectionViewLayoutAttributes]()
    // use a value to keep track of left margin
    var leftMargin: CGFloat = 0.0
    for attributes in attributesForElementsInRect! {
        let refAttributes = attributes
        // assign value if next row
        if (refAttributes.frame.origin.x == self.sectionInset.left) {
            leftMargin = self.sectionInset.left
        } else {
            // set x position of attributes to current margin
            var newLeftAlignedFrame = refAttributes.frame
            newLeftAlignedFrame.origin.x = leftMargin
            if newLeftAlignedFrame.origin.x + newLeftAlignedFrame.size.width > (self.collectionView?.bounds.size.width)! {
                leftMargin = 0.0
                newLeftAlignedFrame.origin.x = 0.0
                if (newAttributesForElementsInRect.last?.frame.origin.y == newLeftAlignedFrame.origin.y){
                    newLeftAlignedFrame.origin.y = newLeftAlignedFrame.origin.y + newLeftAlignedFrame.height + minimumLineSpacing
                }
            }
            refAttributes.frame = newLeftAlignedFrame
        }
        // calculate new value for current margin
        leftMargin += refAttributes.frame.size.width + 10
        newAttributesForElementsInRect.append(refAttributes)
    }
    return newAttributesForElementsInRect
}
}

class DynamicCollectionView: UICollectionView {
override func layoutSubviews() {
    super.layoutSubviews()
    if !__CGSizeEqualToSize(bounds.size, self.intrinsicContentSize) {
        self.invalidateIntrinsicContentSize()
        if self.superview?.superview?.superview is UITableView {
            (self.superview?.superview?.superview as! UITableView).beginUpdates()
            (self.superview?.superview?.superview as! UITableView).endUpdates()
        }
    }
}

override var intrinsicContentSize: CGSize {
    return collectionViewLayout.collectionViewContentSize
}
}

class TagTableCell: UITableViewCell {
@IBOutlet weak var collectionView: UICollectionView!
@IBOutlet weak var flowLayout: SubjectsViewFlowLayout!

override func awakeFromNib() {
    super.awakeFromNib()
    collectionView.register(UINib(nibName: "TagCollectionCell", bundle: nil), forCellWithReuseIdentifier: "TagCollectionCell")
}

func setupCell() {
    let flowLayout = collectionView.collectionViewLayout as? SubjectsViewFlowLayout
    flowLayout?.estimatedItemSize = .init(width: 100, height: 45)

    DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
        self.collectionView.reloadData()
    }
}

func setCollectionViewDataSourceDelegate<D: UICollectionViewDataSource & UICollectionViewDelegate>(_ dataSourceDelegate: D, forRow row: Int) {
    setupCell()
    collectionView.delegate = dataSourceDelegate
    collectionView.dataSource = dataSourceDelegate
    collectionView.tag = row + 1
    collectionView.layoutIfNeeded()
}
}

最佳答案

你只需要在异步方法中调用datasource和datadelegate，同时在tableview单元格中添加UICollectionView

    DispatchQueue.main.async {
        self.collectionView.delegate = dataSourceDelegate
        self.collectionView.dataSource = dataSourceDelegate
    }

关于ios - Collectionview 动态宽度不起作用 Swift，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/54435774/