我有一个包含 2 个部分的 collectionView。第一部分的框架将取决于其中的单元格数量。由于第一部分中的单元格总数 (firstSectionData.count
) 会有所不同,我需要找到第二部分的 CGPoint。我特别需要找出第二部分开始位置的 x/y
值。
框架也足够了,因为我可以从那里提取它们。我怎样才能找到它?
var cv: UICollectionView!
let firstSectionCell = "FirstSectionCell"
let secondSectionCell = "SecondSectionCell"
let secondSectionHeaderView = "SecondSectionHeaderView"
let firstSectionData = [String]()
let secondSectionData = [String]()
let cellHeight: CGFloat = 50
let headerHeight: CGFloat = 60
override func viewDidLoad() {
super.viewDidLoad()
let layout = UICollectionViewFlowLayout()
layout.sectionInset = UIEdgeInsetsMake(0, 0, 0, 0)
layout.scrollDirection = .horizontal
cv = UICollectionView(frame: view.frame, collectionViewLayout: layout)
cv.delegate = self ; cv.dataSource = self
cv.register(FirstSectionCell.self, forCellWithReuseIdentifier: firstSectionCell)
cv.register(SecondSectionCell.self, forCellWithReuseIdentifier: secondSectionCell)
cv.register(SecondSectionHeaderView.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: secondSectionHeaderView)
view.addSubview(cv)
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 2
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if section == 0{
return firstSectionData.count // varies
}
return secondSectionData.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if indexPath.section == 0{
return firstSectionCell = collectionView.dequeueReusableCell(withReuseIdentifier: self.firstSectionCell, for: indexPath) as! FirstSectionCell
}
return secondSectionCell = collectionView.dequeueReusableCell(withReuseIdentifier: self.secondSectionCell, for: indexPath) as! SecondSectionCell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width, height: self.cellHeight) // height is 50
}
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
let headerView: UICollectionReusableView?
if kind == UICollectionElementKindSectionHeader{
let header = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: self.secondSectionHeaderView, for: indexPath) as! SecondSectionHeaderView
headerView = header
}
return headerView!
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
if section == 0{
return CGSize.zero // the first section doesn't have a header
}
return CGSize(width: view.frame.width, height: self.headerHeight) // header height is 60 for the second section
}
最佳答案
此类信息由 Collection View 的布局管理器保存。 Collection View 提供了两种方便的方法:
layoutAttributesForItem(at:)
和:
layoutAttributesForSupplementaryElement(ofKind:at:)
这些返回值 UICollectionViewLayoutAttributes?
。这又具有 frame
等属性。
如果您想要 Collection View 中特定项目的框架,您可以这样做:
let frame = collectionView.layoutAttributesForItem(at: someIndexPath)?.frame
如果你想在 Collection View 中使用节标题的框架,你可以这样做:
let frame = collectionView.layoutAttributesForSupplementaryElement(ofKind: UICollectionElementKindSectionHeader, at: someSectionIndexPath)
关于ios - Swift iOS - 如何找到 CollectionView 第二部分的 CGPoint x/y 值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/50974686/