滚动时 CollectionView FlowLayout 重叠不起作用 [英] CollectionView FlowLayout overlapping when scrolling not working
本文介绍了滚动时 CollectionView FlowLayout 重叠不起作用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
希望你们一切顺利
在这里我创建了一个集合视图流布局，一些场景不起作用，请分享您的参考.这是集合视图
导入 UIKit类视图控制器:UIViewController {@IBOutlet 弱变量集合:UICollectionView！私有让 kCellHeight: CGFloat = UIScreen.main.bounds.width/2+38私有让 kItemSpace: CGFloat = UIScreen.main.bounds.width/2.08懒惰的 var expand_click = false懒惰的 var index_value = [String]()覆盖 func viewDidLoad() {super.viewDidLoad()collection.delegate = 自我collection.dataSource = 自我让布局 = StickyCollectionViewFlowLayout2()layout.minimumLineSpacing = -kItemSpacecollection.collectionViewLayout = 布局集合.reloadData()}}扩展 ViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) ->诠释{返回 15}func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) ->UICollectionViewCell {让 cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewCell", for: indexPath) as！集合视图单元打印(索引"，indexPath.row)返回单元格}func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) ->CGS 大小 {返回CGSize(宽度:view.frame.width-40，高度:kCellHeight)}func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {如果 (15)-1 == indexPath.row {self.showAlert(alertText:"，alertMessage:最后一个单元格")}别的{如果 index_value.contains("(indexPath.row)") {self.showAlert(alertText:"，alertMessage:重定向")expand_click = 真}别的{index_value.removeAll()index_value.append("(indexPath.row)")expand_click = 真单元格数据 = indexPath.rowcollectionView.performBatchUpdates({}，完成:无)}}}}集合视图单元格
类 CollectionViewCell: UICollectionViewCell {@IBOutlet 弱 var 容器:UIView！覆盖 func layoutSubviews() {container.backgroundColor = .whitecontainer.layer.cornerRadius = 13container.layer.shadowRadius = 2container.layer.shadowOpacity = 0.7container.layer.shadowOffset = CGSize(宽度: 0, 高度: 1)container.layer.shadowColor = UIColor.black.withAlphaComponent(0.45).cgColor}}<块引用>
- 单击单元格时，它将展开单元格并移动到其他单元格下方>* 展开的单元格再次单击它将被重定向到另一个页面 forEx(我显示警报)>*最后一个单元格单击它也应该重定向这些都是我自己做的，如果我们有 15 张卡片，它可以正常工作，超过 50 张卡片>滚动不流畅，我们有一个竞争大小的问题，也许我>无法解决问题
**Collection view FlowLayout**类 StickyCollectionViewFlowLayout2: UICollectionViewFlowLayout {var firstItemTransform: CGFloat?覆盖 func layoutAttributesForElements(in rect: CGRect) ->[UICollectionViewLayoutAttributes]?{let items = NSArray (array: super.layoutAttributesForElements(in: rect)!, copyItems: true)print("------------------------------------------------------------------------------------------------------------------------")print("Count-------->",items.count,"<--------Count")print("------------------------------------------------------------------------------------------------------------------------")var headerAttributes: UICollectionViewLayoutAttributes?self.firstItemTransform = nil如果细胞数据！=零{让 min = cellData！打印(分钟)var b = [UICollectionViewLayoutAttributes?]()var a = 假items.forEach({ (object) in让对象=对象为！UICollectionViewLayoutAttributes如果 min == object.indexPath.row {a = 真}别的{如果一个==真{b.附加(对象)}}})对于 b { 中的属性如果属性?.representedElementKind == UICollectionView.elementKindSectionHeader {headerAttributes = 属性}别的 {self.atributeLayout(属性！，headerAttributes:headerAttributes)}}单元格数据 = 无}别的{items.enumerateObjects(using: { (object, idex, stop) -> Void in让属性=对象为！UICollectionViewLayoutAttributes如果 attributes.representedElementKind == UICollectionView.elementKindSectionHeader {headerAttributes = 属性}别的 {self.atributeLayoutReset(属性，headerAttributes:headerAttributes)}})}退货?[UICollectionViewLayoutAttributes]}func atributeLayout(_ attributes: UICollectionViewLayoutAttributes, headerAttributes: UICollectionViewLayoutAttributes?){让 minY = self.collectionView!.bounds.minY + self.collectionView!.contentInset.topvar maxY = attributes.frame.origin.y+attributes.frame.height/2+80如果让 headerAttributes = headerAttributes {maxY -= headerAttributes.bounds.height}让 finalY = max(minY, maxY)var origin = attributes.frame.origin让 deltaY = (finalY - origin.y)/attributes.frame.height + 100如果让 itemTransform = self.firstItemTransform {让 scale = 1 - deltaY * itemTransformattributes.transform = CGAffineTransform(scaleX: scale, y: scale)}origin.y = finalYattributes.frame = CGRect(原点:原点，大小:attributes.frame.size)attributes.zIndex = attributes.indexPath.row}func atributeLayoutReset(_ 属性: UICollectionViewLayoutAttributes, headerAttributes: UICollectionViewLayoutAttributes?){单元格索引 = 无如果 isExpandCell != true {让 minY = self.collectionView!.bounds.minY + self.collectionView!.contentInset.topvar maxY = attributes.frame.origin.y如果让 headerAttributes = headerAttributes {maxY -= headerAttributes.bounds.height}让 finalY = max(minY, maxY)var origin = attributes.frame.origin让 deltaY = (finalY - origin.y)/attributes.frame.height + 100如果让 itemTransform = self.firstItemTransform {让 scale = 1 - deltaY * itemTransformattributes.transform = CGAffineTransform(scaleX: scale, y: scale)}origin.y = finalYattributes.frame = CGRect(原点:原点，大小:attributes.frame.size)attributes.zIndex = attributes.indexPath.row//})}别的{打印(collectionView！.contentInset.top，collectionView！.bounds.minY)让 minY = 0.0 + collectionView!.contentInset.topvar maxY = attributes.frame.origin.y如果让 headerAttributes = headerAttributes {maxY -= headerAttributes.bounds.height}让 finalY = max(minY, maxY)var origin = attributes.frame.origin让 deltaY = (finalY - origin.y)/attributes.frame.height + 100如果让 itemTransform = firstItemTransform {让 scale = 1 - deltaY * itemTransformattributes.transform = CGAffineTransform(scaleX: scale, y: scale)}origin.y = finalYattributes.frame = CGRect(原点:原点，大小:attributes.frame.size)attributes.zIndex = attributes.indexPath.row}}覆盖 func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) ->布尔 {返回假}}如果有人体验过收藏视图，请分享您的参考资料谢谢
解决方案
你好，请试试我的代码.我在 iPhone 模拟器上测试过，效果很好.
导入 SwiftUI结构卡视图:查看 {静态让 CARD_HEIGHT: CGFloat = 200静态让 CARD_WIDTH: CGFloat = 300静态让 TAB_HEIGHT: CGFloat = 30@State var selected:Int?= 无让卡:Intvar body: 一些视图 {滚动视图 {ZStack(对齐:.top){ForEach(0 ..编辑
这样使用
让 swiftUIview = CardView(cards: 10, onCardTapped: { card inprint("卡号(卡)点击")})让 uiViewController = UIHostingController(rootView: swiftUIview)Gif 因过时而被删除.
I hope you all working fine
Here I have created a collection view flow layouts some scenarios not working, please share your references. here is the collection view
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var collection: UICollectionView!
private let kCellHeight: CGFloat = UIScreen.main.bounds.width/2+38
private let kItemSpace: CGFloat = UIScreen.main.bounds.width/2.08
lazy var expand_click = false
lazy var index_value = [String]()
override func viewDidLoad() {
super.viewDidLoad()
collection.delegate = self
collection.dataSource = self
let layout = StickyCollectionViewFlowLayout2()
layout.minimumLineSpacing = -kItemSpace
collection.collectionViewLayout = layout
collection.reloadData()
}
}
extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 15
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewCell", for: indexPath) as! CollectionViewCell
print("Index",indexPath.row)
return cell
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: view.frame.width-40, height: kCellHeight)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if (15)-1 == indexPath.row {
self.showAlert(alertText: "", alertMessage: "last Cell")
}else{
if index_value.contains("(indexPath.row)") {
self.showAlert(alertText: "", alertMessage: "Redirect")
expand_click = true
}else{
index_value.removeAll()
index_value.append("(indexPath.row)")
expand_click = true
cellData = indexPath.row
collectionView.performBatchUpdates({
}, completion: nil)
}
}
}
}
collection view cells
class CollectionViewCell: UICollectionViewCell {
@IBOutlet weak var container: UIView!
override func layoutSubviews() {
container.backgroundColor = .white
container.layer.cornerRadius = 13
container.layer.shadowRadius = 2
container.layer.shadowOpacity = 0.7
container.layer.shadowOffset = CGSize(width: 0, height: 1)
container.layer.shadowColor = UIColor.black.withAlphaComponent(0.45).cgColor
}
}
- When clicked cell it will be expanding the cell and moved to be under the other the cells > * Expanded cell again click it will be redirected to another page forEx (I showed alert) > * the last cell click it's should also redirect These are all I have done my self if we have 15 cards it working fine more than 50 cards > not smooth scrolling and we have a problem for contending size maybe I > could not solve the issue
**Collection view FlowLayout**
class StickyCollectionViewFlowLayout2: UICollectionViewFlowLayout {
var firstItemTransform: CGFloat?
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
let items = NSArray (array: super.layoutAttributesForElements(in: rect)!, copyItems: true)
print("------------------------------------------------------------------------------------------------------------------------")
print("Count-------->",items.count,"<--------Count")
print("------------------------------------------------------------------------------------------------------------------------")
var headerAttributes: UICollectionViewLayoutAttributes?
self.firstItemTransform = nil
if cellData != nil {
let min = cellData!
print(min)
var b = [UICollectionViewLayoutAttributes?]()
var a = false
items.forEach({ (object) in
let object = object as! UICollectionViewLayoutAttributes
if min == object.indexPath.row {
a = true
}else{
if a == true {
b.append(object)
}
}
})
for attributes in b {
if attributes?.representedElementKind == UICollectionView.elementKindSectionHeader {
headerAttributes = attributes
}
else {
self.atributeLayout(attributes!, headerAttributes: headerAttributes)
}
}
cellData = nil
}else{
items.enumerateObjects(using: { (object, idex, stop) -> Void in
let attributes = object as! UICollectionViewLayoutAttributes
if attributes.representedElementKind == UICollectionView.elementKindSectionHeader {
headerAttributes = attributes
}
else {
self.atributeLayoutReset(attributes, headerAttributes: headerAttributes)
}
})
}
return items as? [UICollectionViewLayoutAttributes]
}
func atributeLayout(_ attributes: UICollectionViewLayoutAttributes, headerAttributes: UICollectionViewLayoutAttributes?){
let minY = self.collectionView!.bounds.minY + self.collectionView!.contentInset.top
var maxY = attributes.frame.origin.y+attributes.frame.height/2+80
if let headerAttributes = headerAttributes {
maxY -= headerAttributes.bounds.height
}
let finalY = max(minY, maxY)
var origin = attributes.frame.origin
let deltaY = (finalY - origin.y) / attributes.frame.height + 100
if let itemTransform = self.firstItemTransform {
let scale = 1 - deltaY * itemTransform
attributes.transform = CGAffineTransform(scaleX: scale, y: scale)
}
origin.y = finalY
attributes.frame = CGRect(origin: origin, size: attributes.frame.size)
attributes.zIndex = attributes.indexPath.row
}
func atributeLayoutReset(_ attributes: UICollectionViewLayoutAttributes, headerAttributes: UICollectionViewLayoutAttributes?){
cellIndex = nil
if isExpandCell != true {
let minY = self.collectionView!.bounds.minY + self.collectionView!.contentInset.top
var maxY = attributes.frame.origin.y
if let headerAttributes = headerAttributes {
maxY -= headerAttributes.bounds.height
}
let finalY = max(minY, maxY)
var origin = attributes.frame.origin
let deltaY = (finalY - origin.y) / attributes.frame.height + 100
if let itemTransform = self.firstItemTransform {
let scale = 1 - deltaY * itemTransform
attributes.transform = CGAffineTransform(scaleX: scale, y: scale)
}
origin.y = finalY
attributes.frame = CGRect(origin: origin, size: attributes.frame.size)
attributes.zIndex = attributes.indexPath.row
// })
}else{
print(collectionView!.contentInset.top,collectionView!.bounds.minY)
let minY = 0.0 + collectionView!.contentInset.top
var maxY = attributes.frame.origin.y
if let headerAttributes = headerAttributes {
maxY -= headerAttributes.bounds.height
}
let finalY = max(minY, maxY)
var origin = attributes.frame.origin
let deltaY = (finalY - origin.y) / attributes.frame.height + 100
if let itemTransform = firstItemTransform {
let scale = 1 - deltaY * itemTransform
attributes.transform = CGAffineTransform(scaleX: scale, y: scale)
}
origin.y = finalY
attributes.frame = CGRect(origin: origin, size: attributes.frame.size)
attributes.zIndex = attributes.indexPath.row
}
}
override func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
return false
}
}
if anyone experienced collection view please share me your references Thank you
解决方案
Hello please try my code. I have tested on an iPhone simulator and it works great.
import SwiftUI
struct CardView: View {
static let CARD_HEIGHT: CGFloat = 200
static let CARD_WIDTH: CGFloat = 300
static let TAB_HEIGHT: CGFloat = 30
@State var selected: Int? = nil
let cards: Int
var body: some View {
ScrollView {
ZStack(alignment: .top) {
ForEach(0 ..< cards) { card_i in
Button {
withAnimation {
self.selected = self.selected == card_i ? nil : card_i
}
print("A card was tapped. Do something with card_i here")
} label: { self.card }
.buttonStyle(PlainButtonStyle())
.frame(width: Self.CARD_WIDTH, height: Self.CARD_HEIGHT, alignment: .top)
.offset(x: .zero, y: CGFloat(card_i) * Self.TAB_HEIGHT + ((selected ?? cards + 1) < card_i ? Self.CARD_HEIGHT - Self.TAB_HEIGHT / 2 : 0))
}
}
.frame(height: Self.CARD_HEIGHT + Self.TAB_HEIGHT * CGFloat(cards), alignment: .top)
.padding()
}
}
var card: some View {
RoundedRectangle(cornerRadius: 17, style: .continuous)
.fill(Color.gray)
.overlay(RoundedRectangle(cornerRadius: 17, style: .continuous).stroke(Color.black, lineWidth: 5))
}
}
Edit
Use it like this
let swiftUIview = CardView(cards: 10, onCardTapped: { card in
print("card number (card) tapped")
})
let uiViewController = UIHostingController(rootView: swiftUIview)
Gif removed because outdated.
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