拖动和重新排序 - 带有部分的 UICollectionview [英] Drag and reorder - UICollectionview with sections
本文介绍了拖动和重新排序 - 带有部分的 UICollectionview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
是否可以从collectionview - iOS 9从一个部分拖动和重新排序到另一部分.
每次从第 1 部分拖放到第 4 部分时，都会遇到崩溃，
-[UICollectionView _endItemAnimationsWithInvalidationContext:tentativelyForReordering:
中的断言失败 func collectionView(collectionView: UICollectionView, moveItemAtIndexPath sourceIndexPath: NSIndexPath,toIndexPath destinationIndexPath: NSIndexPath){让序列 = ArrayrelatedSequence[sourceIndexPath.section] 为！SEQ_SequencerelIndexCards = 序列.rel_indexCard如果 relIndexCards.count >0 {数组索引卡 = []让 arr1: NSMutableArray = []对于 relIndexCards 中的项目 {arr1.addObject(项目)}让描述符:NSSortDescriptor = NSSortDescriptor(键:keyP_IndexCard_ID"，升序:false)让 arrNew:NSArray = arr1.sortedArrayUsingDescriptors([descriptor])让我 = 0对于 arrNew 中的项目{ArrayIndexcard.insert(项目为！NSManagedObject，atIndex:i)我+1}}让 temp = self.ArrayIndexcard.removeAtIndex(sourceIndexPath.item)self.ArrayIndexcard.insert(temp, atIndex:destinationIndexPath.item)如果 islongPressed_Indexcard == true{islongPressed_Indexcard = false让 managedContext = appDelegate.managedObjectContext变量 i = 0用于更新 ArrayIndexcard{我=我+1update.setValue(i, forKey: "keyP_IndexCard_ID")}做 {尝试 managedContext.save()collectionview_in_outline.reloadData()} 捕捉让 nserror 作为 NSError {print("未解决的错误 (nserror), (nserror.userInfo)")中止()}}}下面是我的流程布局代码，
类 CustomFlowLayout: UICollectionViewFlowLayout {var longPress:UILongPressGestureRecognizer！var originalIndexPath: NSIndexPath?var draggingIndexPath: NSIndexPath?var draggingView:UIView?var dragOffset = CGPointZero覆盖函数prepareLayout(){super.prepareLayout()安装手势识别器()}func applyDraggingAttributes(属性:UICollectionViewLayoutAttributes){属性.alpha = 0}覆盖 func layoutAttributesForElementsInRect(rect: CGRect) ->[UICollectionViewLayoutAttributes]?{让属性 = super.layoutAttributesForElementsInRect(rect)属性?.forEach { 一个在如果 a.indexPath == draggingIndexPath {如果 a.representedElementCategory == .Cell {self.applyDraggingAttributes(a)}}}返回属性}覆盖 func layoutAttributesForItemAtIndexPath(indexPath: NSIndexPath) ->UICollectionViewLayoutAttributes?{让属性 = super.layoutAttributesForItemAtIndexPath(indexPath)if let attributes = attributes where indexPath == draggingIndexPath {如果 attributes.representedElementCategory == .Cell {applyDraggingAttributes(属性)}}返回属性}func installGestureRecognizer() {如果长按 == 无 {longPress = UILongPressGestureRecognizer(目标:自我，动作:#selector(CustomFlowLayout.handleLongPress(_:)))longPress.minimumPressDuration = 0.2collectionView?.addGestureRecognizer(longPress)}}func handleLongPress(longPress:UILongPressGestureRecognizer){让 location = longPress.locationInView(collectionView!)切换 longPress.state {case .Began: startDragAtLocation(location)case .Changed: updateDragAtLocation(location)case .Ended: endDragAtLocation(location)默认:休息}}func startDragAtLocation(位置:CGPoint){守卫让 cv = collectionView else { return }守卫让 indexPath = cv.indexPathForItemAtPoint(location) else { return }保护 cv.dataSource?.collectionView?(cv, canMoveItemAtIndexPath: indexPath) == true else { return }守卫让细胞 = cv.cellForItemAtIndexPath(indexPath) else { return }原始索引路径 = 索引路径拖动索引路径 = 索引路径draggingView = cell.snapshotViewAfterScreenUpdates(true)draggingView!.frame = cell.framecv.addSubview(拖动视图！)dragOffset = CGPointMake(draggingView!.center.x - location.x, draggingView!.center.y - location.y)draggingView?.layer.shadowPath = UIBezierPath(rect: draggingView!.bounds).CGPathdraggingView?.layer.shadowColor = UIColor.blackColor().CGColordraggingView?.layer.shadowOpacity = 0.8draggingView?.layer.shadowRadius = 10无效布局()UIView.animateWithDuration(0.4, delay: 0, usingSpringWithDamping: 0.4, initialSpringVelocity: 0, options: [], animations: {self.draggingView?.alpha = 0.95self.draggingView?.transform = CGAffineTransformMakeScale(1.2, 1.2)}，完成:无)}func updateDragAtLocation(位置:CGPoint){守卫让视图 = draggingView else { return }守卫让 cv = collectionView else { return }view.center = CGPointMake(location.x + dragOffset.x, location.y + dragOffset.y)如果让 newIndexPath = cv.indexPathForItemAtPoint(location) {**cv.moveItemAtIndexPath(draggingIndexPath!, toIndexPath: newIndexPath)**拖动索引路径 = 新索引路径}}func endDragAtLocation(位置:CGPoint){守卫让dragView = draggingView else { return }守卫让 indexPath = draggingIndexPath else { return }守卫让 cv = collectionView else { return }守卫让数据源= cv.dataSource else { return }让 targetCenter = datasource.collectionView(cv, cellForItemAtIndexPath: indexPath).center让 shadowFade = CABasicAnimation(keyPath: "shadowOpacity")shadowFade.fromValue = 0.8shadowFade.toValue = 0shadowFade.duration = 0.4dragView.layer.addAnimation(shadowFade, forKey: "shadowFade")UIView.animateWithDuration(0.4, delay: 0, usingSpringWithDamping: 0.4, initialSpringVelocity: 0, options: [], animations: {dragView.center = targetCenterdragView.transform = CGAffineTransformIdentity}) {(已完成)在如果 !indexPath.isEqual(self.originalIndexPath!) {datasource.collectionView?(cv, moveItemAtIndexPath: self.originalIndexPath!, toIndexPath: indexPath)}dragView.removeFromSuperview()self.draggingIndexPath = nilself.draggingView = nilself.invalidateLayout()}NSNotificationCenter.defaultCenter().postNotificationName("Needtorefresh", object: nil)collectionView?.reloadData()}}
解决方案
详情
- Xcode 10.2 (10E125)、Swift 5
链接
完整样本
<块引用>视图控制器
导入 UIKit枚举细胞模型 {案例简单(文本:字符串)案例可用ToDrop}类视图控制器:UIViewController {私有惰性 var cellIdentifier = "cellIdentifier"私有惰性 var 补充视图标识符 = 补充视图标识符"私有惰性 var 部分 = 10私有惰性 var itemsInSection = 2私有惰性 var numberOfElementsInRow = 3私有惰性 var 数据:[[CellModel]] = {变量计数 = 0return (0 ..细胞模型在计数 += 1返回 .simple(文本:单元格 (计数)")}}}()覆盖 func viewDidLoad() {super.viewDidLoad()让 collectionViewFlowLayout = UICollectionViewFlowLayout()collectionViewFlowLayout.minimumLineSpacing = 5collectionViewFlowLayout.minimumInteritemSpacing = 5让 _numberOfElementsInRow = CGFloat(numberOfElementsInRow)让 allWidthBetwenCells = _numberOfElementsInRow == 0 ?0:collectionViewFlowLayout.minimumInteritemSpacing*(_numberOfElementsInRow-1)让宽度 = (view.frame.width - allWidthBetwenCells)/_numberOfElementsInRowcollectionViewFlowLayout.itemSize = CGSize(宽度:宽度，高度:宽度)collectionViewFlowLayout.headerReferenceSize = CGSize(宽度:0，高度:40)让 collectionView = UICollectionView(frame: .zero, collectionViewLayout: collectionViewFlowLayout)collectionView.backgroundColor = .whiteview.addSubview(collectionView)collectionView.translatesAutoresizingMaskIntoConstraints = falsecollectionView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = truecollectionView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = truecollectionView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor).isActive = truecollectionView.rightAnchor.constraint(equalTo: view.safeAreaLayoutGuide.rightAnchor).isActive = truecollectionView.register(CollectionViewCell.self, forCellWithReuseIdentifier: cellIdentifier)collectionView.register(SupplementaryView.self,对于SupplementaryViewOfKind:UICollectionView.elementKindSectionHeader，withReuseIdentifier:补充视图标识符)collectionView.dragInteractionEnabled = truecollectionView.reorderingCadence = .fastcollectionView.dropDelegate = selfcollectionView.dragDelegate = selfcollectionView.delegate = selfcollectionView.dataSource = 自我}}扩展 ViewController: UICollectionViewDelegate { }扩展视图控制器:UICollectionViewDataSource {func numberOfSections(in collectionView: UICollectionView) ->整数 { 返回数据.count }func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) ->诠释{返回数据[节].count}func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) ->UICollectionViewCell {切换数据[indexPath.section][indexPath.item] {case .simple(让文本):让 cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as！集合视图单元cell.label?.text = 文本cell.backgroundColor = .gray返回单元格案例 .availableToDrop:让 cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as！集合视图单元cell.backgroundColor = UIColor.green.withAlphaComponent(0.3)返回单元格}}func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) ->UICollectionReusableView {让 headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier:supplementaryViewIdentifier, for: indexPath as IndexPath) as！补充观点返回标题视图}}扩展视图控制器:UICollectionViewDragDelegate {func collectionView(_ collectionView: UICollectionView, itemsForBeginning session: UIDragSession, at indexPath: IndexPath) ->[UIDragItem] {让 itemProvider = NSItemProvider(object: "(indexPath)" as NSString)让 dragItem = UIDragItem(itemProvider: itemProvider)dragItem.localObject = 数据[indexPath.section][indexPath.row]返回[拖动项]}func collectionView(_ collectionView: UICollectionView, itemsForAddingTo session: UIDragSession, at indexPath: IndexPath, point: CGPoint) ->[UIDragItem] {让 itemProvider = NSItemProvider(object: "(indexPath)" as NSString)让 dragItem = UIDragItem(itemProvider: itemProvider)dragItem.localObject = 数据[indexPath.section][indexPath.row]返回[拖动项]}func collectionView(_ collectionView: UICollectionView, dragSessionWillBegin session: UIDragSession) {var itemsToInsert = [索引路径]()(0 ..UICollectionViewDropProposal {如果collectionView.hasActiveDrag，让destinationIndexPath = destinationIndexPath {切换数据[destinationIndexPath.section][destinationIndexPath.row] {案例.简单:返回 UICollectionViewDropProposal(操作:.move，意图:.insertAtDestinationIndexPath)案例 .availableToDrop:返回 UICollectionViewDropProposal(操作:.move，意图:.insertIntoDestinationIndexPath)}} else { 返回 UICollectionViewDropProposal(操作: .forbidden) }}私人 func reorderItems(协调器:UICollectionViewDropCoordinator，destinationIndexPath:IndexPath，collectionView:UICollectionView){让 items = coordinator.items如果 items.count == 1，让 item = items.first，让 sourceIndexPath = item.sourceIndexPath,让localObject = item.dragItem.localObject 为?细胞模型 {collectionView.performBatchUpdates ({数据[sourceIndexPath.section].remove(at: sourceIndexPath.item)数据[destinationIndexPath.section].insert(localObject, at:destinationIndexPath.item)collectionView.deleteItems(在:[sourceIndexPath])collectionView.insertItems(在:[destinationIndexPath])})}}私人 func copyItems(协调器:UICollectionViewDropCoordinator，destinationIndexPath:IndexPath，collectionView:UICollectionView){collectionView.performBatchUpdates({var indexPaths = [索引路径]()for (index, item) in coordinator.items.enumerated() {如果让 localObject = item.dragItem.localObject 为?细胞模型 {让 indexPath = IndexPath(row:destinationIndexPath.row + index, section:destinationIndexPath.section)数据[indexPath.section].insert(localObject, at: indexPath.row)indexPaths.append(indexPath)}}collectionView.insertItems(在:indexPaths)})}} <块引用>
细胞
导入 UIKit类 CollectionViewCell: UICollectionViewCell {弱变量标签:UILabel?覆盖初始化(帧:CGRect){超级初始化(帧:帧)clipsToBounds = true让 label = UILabel(frame: .zero)label.contentMode = .scaleAspectFill添加子视图(标签)label.translatesAutoresizingMaskIntoConstraints = falselabel.topAnchor.constraint(equalTo: topAnchor).isActive = truelabel.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = truelabel.leftAnchor.constraint(equalTo: leftAnchor).isActive = truelabel.rightAnchor.constraint(equalTo: rightAnchor).isActive = true标签.textAlignment = .center标签.textColor = .whiteself.label = 标签layer.borderWidth = 1layer.borderColor = UIColor.white.cgColor背景颜色 = .white}需要初始化?(编码器 aDecoder:NSCoder){super.init(编码器:aDecoder)}覆盖 func prepareForReuse() {super.prepareForReuse()标签?.text = nil背景颜色 = .white}}导入 UIKit类补充视图:UICollectionReusableView {弱变量标签:UILabel?覆盖初始化(帧:CGRect){超级初始化(帧:帧)背景颜色 = UIColor.blue.withAlphaComponent(0.7)}需要初始化?(编码器 aDecoder:NSCoder){super.init(编码器:aDecoder)}}结果
Is that possible to do drag and reorder from one section to another section from collectionview - iOS 9.
Every time am dragging from 1st section to drop at 4th section am getting below crash,
Assertion failure in -[UICollectionView _endItemAnimationsWithInvalidationContext:tentativelyForReordering:
func collectionView(collectionView: UICollectionView, moveItemAtIndexPath sourceIndexPath: NSIndexPath,toIndexPath destinationIndexPath: NSIndexPath)
{
let sequence = ArrayrelatedSequence[sourceIndexPath.section] as! SEQ_Sequence
relIndexCards = sequence.rel_indexCard
if relIndexCards.count > 0 {
ArrayIndexcard = []
let arr1: NSMutableArray = []
for item in relIndexCards {
arr1.addObject(item)
}
let descriptor: NSSortDescriptor = NSSortDescriptor(key: "keyP_IndexCard_ID", ascending: false)
let arrNew:NSArray = arr1.sortedArrayUsingDescriptors([descriptor])
let i = 0
for item in arrNew
{
ArrayIndexcard.insert(item as! NSManagedObject, atIndex: i)
i+1
}
}
let temp = self.ArrayIndexcard.removeAtIndex(sourceIndexPath.item)
self.ArrayIndexcard.insert(temp, atIndex: destinationIndexPath.item)
if islongPressed_Indexcard == true
{
islongPressed_Indexcard = false
let managedContext = appDelegate.managedObjectContext
var i = 0
for update in ArrayIndexcard
{
i = i+1
update.setValue(i, forKey: "keyP_IndexCard_ID")
}
do {
try managedContext.save()
collectionview_in_outline.reloadData()
} catch let nserror as NSError {
print("Unresolved error (nserror), (nserror.userInfo)")
abort()
}
}
}
My flow layout code below,
class CustomFlowLayout: UICollectionViewFlowLayout {
var longPress: UILongPressGestureRecognizer!
var originalIndexPath: NSIndexPath?
var draggingIndexPath: NSIndexPath?
var draggingView: UIView?
var dragOffset = CGPointZero
override func prepareLayout() {
super.prepareLayout()
installGestureRecognizer()
}
func applyDraggingAttributes(attributes: UICollectionViewLayoutAttributes) {
attributes.alpha = 0
}
override func layoutAttributesForElementsInRect(rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
let attributes = super.layoutAttributesForElementsInRect(rect)
attributes?.forEach { a in
if a.indexPath == draggingIndexPath {
if a.representedElementCategory == .Cell {
self.applyDraggingAttributes(a)
}
}
}
return attributes
}
override func layoutAttributesForItemAtIndexPath(indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes? {
let attributes = super.layoutAttributesForItemAtIndexPath(indexPath)
if let attributes = attributes where indexPath == draggingIndexPath {
if attributes.representedElementCategory == .Cell {
applyDraggingAttributes(attributes)
}
}
return attributes
}
func installGestureRecognizer() {
if longPress == nil {
longPress = UILongPressGestureRecognizer(target: self, action: #selector(CustomFlowLayout.handleLongPress(_:)))
longPress.minimumPressDuration = 0.2
collectionView?.addGestureRecognizer(longPress)
}
}
func handleLongPress(longPress: UILongPressGestureRecognizer) {
let location = longPress.locationInView(collectionView!)
switch longPress.state {
case .Began: startDragAtLocation(location)
case .Changed: updateDragAtLocation(location)
case .Ended: endDragAtLocation(location)
default:
break
}
}
func startDragAtLocation(location: CGPoint) {
guard let cv = collectionView else { return }
guard let indexPath = cv.indexPathForItemAtPoint(location) else { return }
guard cv.dataSource?.collectionView?(cv, canMoveItemAtIndexPath: indexPath) == true else { return }
guard let cell = cv.cellForItemAtIndexPath(indexPath) else { return }
originalIndexPath = indexPath
draggingIndexPath = indexPath
draggingView = cell.snapshotViewAfterScreenUpdates(true)
draggingView!.frame = cell.frame
cv.addSubview(draggingView!)
dragOffset = CGPointMake(draggingView!.center.x - location.x, draggingView!.center.y - location.y)
draggingView?.layer.shadowPath = UIBezierPath(rect: draggingView!.bounds).CGPath
draggingView?.layer.shadowColor = UIColor.blackColor().CGColor
draggingView?.layer.shadowOpacity = 0.8
draggingView?.layer.shadowRadius = 10
invalidateLayout()
UIView.animateWithDuration(0.4, delay: 0, usingSpringWithDamping: 0.4, initialSpringVelocity: 0, options: [], animations: {
self.draggingView?.alpha = 0.95
self.draggingView?.transform = CGAffineTransformMakeScale(1.2, 1.2)
}, completion: nil)
}
func updateDragAtLocation(location: CGPoint) {
guard let view = draggingView else { return }
guard let cv = collectionView else { return }
view.center = CGPointMake(location.x + dragOffset.x, location.y + dragOffset.y)
if let newIndexPath = cv.indexPathForItemAtPoint(location) {
**cv.moveItemAtIndexPath(draggingIndexPath!, toIndexPath: newIndexPath)**
draggingIndexPath = newIndexPath
}
}
func endDragAtLocation(location: CGPoint) {
guard let dragView = draggingView else { return }
guard let indexPath = draggingIndexPath else { return }
guard let cv = collectionView else { return }
guard let datasource = cv.dataSource else { return }
let targetCenter = datasource.collectionView(cv, cellForItemAtIndexPath: indexPath).center
let shadowFade = CABasicAnimation(keyPath: "shadowOpacity")
shadowFade.fromValue = 0.8
shadowFade.toValue = 0
shadowFade.duration = 0.4
dragView.layer.addAnimation(shadowFade, forKey: "shadowFade")
UIView.animateWithDuration(0.4, delay: 0, usingSpringWithDamping: 0.4, initialSpringVelocity: 0, options: [], animations: {
dragView.center = targetCenter
dragView.transform = CGAffineTransformIdentity
}) { (completed) in
if !indexPath.isEqual(self.originalIndexPath!) {
datasource.collectionView?(cv, moveItemAtIndexPath: self.originalIndexPath!, toIndexPath: indexPath)
}
dragView.removeFromSuperview()
self.draggingIndexPath = nil
self.draggingView = nil
self.invalidateLayout()
}
NSNotificationCenter.defaultCenter().postNotificationName("Needtorefresh", object: nil)
collectionView?.reloadData()
}
}
解决方案
Details
- Xcode 10.2 (10E125), Swift 5
Links
Coding for iOS 11: How to drag & drop into collections & tables
Full Sample
ViewController
import UIKit
enum CellModel {
case simple(text: String)
case availableToDrop
}
class ViewController: UIViewController {
private lazy var cellIdentifier = "cellIdentifier"
private lazy var supplementaryViewIdentifier = "supplementaryViewIdentifier"
private lazy var sections = 10
private lazy var itemsInSection = 2
private lazy var numberOfElementsInRow = 3
private lazy var data: [[CellModel]] = {
var count = 0
return (0 ..< sections).map { _ in
return (0 ..< itemsInSection).map { _ -> CellModel in
count += 1
return .simple(text: "cell (count)")
}
}
}()
override func viewDidLoad() {
super.viewDidLoad()
let collectionViewFlowLayout = UICollectionViewFlowLayout()
collectionViewFlowLayout.minimumLineSpacing = 5
collectionViewFlowLayout.minimumInteritemSpacing = 5
let _numberOfElementsInRow = CGFloat(numberOfElementsInRow)
let allWidthBetwenCells = _numberOfElementsInRow == 0 ? 0 : collectionViewFlowLayout.minimumInteritemSpacing*(_numberOfElementsInRow-1)
let width = (view.frame.width - allWidthBetwenCells)/_numberOfElementsInRow
collectionViewFlowLayout.itemSize = CGSize(width: width, height: width)
collectionViewFlowLayout.headerReferenceSize = CGSize(width: 0, height: 40)
let collectionView = UICollectionView(frame: .zero, collectionViewLayout: collectionViewFlowLayout)
collectionView.backgroundColor = .white
view.addSubview(collectionView)
collectionView.translatesAutoresizingMaskIntoConstraints = false
collectionView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
collectionView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
collectionView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor).isActive = true
collectionView.rightAnchor.constraint(equalTo: view.safeAreaLayoutGuide.rightAnchor).isActive = true
collectionView.register(CollectionViewCell.self, forCellWithReuseIdentifier: cellIdentifier)
collectionView.register(SupplementaryView.self,
forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader,
withReuseIdentifier: supplementaryViewIdentifier)
collectionView.dragInteractionEnabled = true
collectionView.reorderingCadence = .fast
collectionView.dropDelegate = self
collectionView.dragDelegate = self
collectionView.delegate = self
collectionView.dataSource = self
}
}
extension ViewController: UICollectionViewDelegate { }
extension ViewController: UICollectionViewDataSource {
func numberOfSections(in collectionView: UICollectionView) -> Int { return data.count }
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return data[section].count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
switch data[indexPath.section][indexPath.item] {
case .simple(let text):
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! CollectionViewCell
cell.label?.text = text
cell.backgroundColor = .gray
return cell
case .availableToDrop:
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! CollectionViewCell
cell.backgroundColor = UIColor.green.withAlphaComponent(0.3)
return cell
}
}
func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: supplementaryViewIdentifier, for: indexPath as IndexPath) as! SupplementaryView
return headerView
}
}
extension ViewController: UICollectionViewDragDelegate {
func collectionView(_ collectionView: UICollectionView, itemsForBeginning session: UIDragSession, at indexPath: IndexPath) -> [UIDragItem] {
let itemProvider = NSItemProvider(object: "(indexPath)" as NSString)
let dragItem = UIDragItem(itemProvider: itemProvider)
dragItem.localObject = data[indexPath.section][indexPath.row]
return [dragItem]
}
func collectionView(_ collectionView: UICollectionView, itemsForAddingTo session: UIDragSession, at indexPath: IndexPath, point: CGPoint) -> [UIDragItem] {
let itemProvider = NSItemProvider(object: "(indexPath)" as NSString)
let dragItem = UIDragItem(itemProvider: itemProvider)
dragItem.localObject = data[indexPath.section][indexPath.row]
return [dragItem]
}
func collectionView(_ collectionView: UICollectionView, dragSessionWillBegin session: UIDragSession) {
var itemsToInsert = [IndexPath]()
(0 ..< data.count).forEach {
itemsToInsert.append(IndexPath(item: data[$0].count, section: $0))
data[$0].append(.availableToDrop)
}
collectionView.insertItems(at: itemsToInsert)
}
func collectionView(_ collectionView: UICollectionView, dragSessionDidEnd session: UIDragSession) {
var removeItems = [IndexPath]()
for section in 0..<data.count {
for item in 0..<data[section].count {
switch data[section][item] {
case .availableToDrop: removeItems.append(IndexPath(item: item, section: section))
case .simple: break
}
}
}
removeItems.forEach { data[$0.section].remove(at: $0.item) }
collectionView.deleteItems(at: removeItems)
}
}
extension ViewController: UICollectionViewDropDelegate {
func collectionView(_ collectionView: UICollectionView, performDropWith coordinator: UICollectionViewDropCoordinator) {
let destinationIndexPath: IndexPath
if let indexPath = coordinator.destinationIndexPath {
destinationIndexPath = indexPath
} else {
let section = collectionView.numberOfSections - 1
let row = collectionView.numberOfItems(inSection: section)
destinationIndexPath = IndexPath(row: row, section: section)
}
switch coordinator.proposal.operation {
case .move:
reorderItems(coordinator: coordinator, destinationIndexPath:destinationIndexPath, collectionView: collectionView)
case .copy:
copyItems(coordinator: coordinator, destinationIndexPath: destinationIndexPath, collectionView: collectionView)
default: return
}
}
func collectionView(_ collectionView: UICollectionView, canHandle session: UIDropSession) -> Bool { return true }
func collectionView(_ collectionView: UICollectionView, dropSessionDidUpdate session: UIDropSession, withDestinationIndexPath destinationIndexPath: IndexPath?) -> UICollectionViewDropProposal {
if collectionView.hasActiveDrag, let destinationIndexPath = destinationIndexPath {
switch data[destinationIndexPath.section][destinationIndexPath.row] {
case .simple:
return UICollectionViewDropProposal(operation: .move, intent: .insertAtDestinationIndexPath)
case .availableToDrop:
return UICollectionViewDropProposal(operation: .move, intent: .insertIntoDestinationIndexPath)
}
} else { return UICollectionViewDropProposal(operation: .forbidden) }
}
private func reorderItems(coordinator: UICollectionViewDropCoordinator, destinationIndexPath: IndexPath, collectionView: UICollectionView) {
let items = coordinator.items
if items.count == 1, let item = items.first,
let sourceIndexPath = item.sourceIndexPath,
let localObject = item.dragItem.localObject as? CellModel {
collectionView.performBatchUpdates ({
data[sourceIndexPath.section].remove(at: sourceIndexPath.item)
data[destinationIndexPath.section].insert(localObject, at: destinationIndexPath.item)
collectionView.deleteItems(at: [sourceIndexPath])
collectionView.insertItems(at: [destinationIndexPath])
})
}
}
private func copyItems(coordinator: UICollectionViewDropCoordinator, destinationIndexPath: IndexPath, collectionView: UICollectionView) {
collectionView.performBatchUpdates({
var indexPaths = [IndexPath]()
for (index, item) in coordinator.items.enumerated() {
if let localObject = item.dragItem.localObject as? CellModel {
let indexPath = IndexPath(row: destinationIndexPath.row + index, section: destinationIndexPath.section)
data[indexPath.section].insert(localObject, at: indexPath.row)
indexPaths.append(indexPath)
}
}
collectionView.insertItems(at: indexPaths)
})
}
}
Cells
import UIKit
class CollectionViewCell: UICollectionViewCell {
weak var label: UILabel?
override init(frame: CGRect) {
super.init(frame: frame)
clipsToBounds = true
let label = UILabel(frame: .zero)
label.contentMode = .scaleAspectFill
addSubview(label)
label.translatesAutoresizingMaskIntoConstraints = false
label.topAnchor.constraint(equalTo: topAnchor).isActive = true
label.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
label.leftAnchor.constraint(equalTo: leftAnchor).isActive = true
label.rightAnchor.constraint(equalTo: rightAnchor).isActive = true
label.textAlignment = .center
label.textColor = .white
self.label = label
layer.borderWidth = 1
layer.borderColor = UIColor.white.cgColor
backgroundColor = .white
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func prepareForReuse() {
super.prepareForReuse()
label?.text = nil
backgroundColor = .white
}
}
import UIKit
class SupplementaryView: UICollectionReusableView {
weak var label: UILabel?
override init(frame: CGRect) {
super.init(frame: frame)
backgroundColor = UIColor.blue.withAlphaComponent(0.7)
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
}
Result
这篇关于拖动和重新排序 - 带有部分的 UICollectionview的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
