所以我有一些代码用于自动滚动collectionView，它给了我很多问题。它基于一个定时器工作，该定时器每3.5秒调用一个特定的函数来滚动到collectionView中的某个项目。代码包含在belwo
中import UIKit
class HomeFeedCell: UICollectionViewCell, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout, UIScrollViewDelegate {
var homeFeedController: HomeFeedController?
let emptyView = UIView()
//Timer user for call autoscroller of top collection view
private var timer:Timer?
var scrollTimer = Timer()
private let cellId = "cellId"
var featuredEvents: [Event]?{
didSet {
homeFeedCollectionView.reloadData()
}
}
var titles: String? {
didSet {
guard let titles = titles else {
return
}
// let attributedText = NSMutableAttributedString(string: titles, attributes: [NSAttributedStringKey.font: UIFont.boldSystemFont(ofSize: 100)])
sectionNameLabel.text = titles
// sectionNameLabel.attributedText = attributedText
}
}
override init(frame: CGRect) {
super.init(frame: frame)
self.setTimer()
setupViews()
}
func setTimer(){
//auto scroll method to call every 2.5 seconds interval
self.timer = Timer.scheduledTimer(timeInterval: 5, target: self, selector: #selector(self.startTimer(theTimer:)), userInfo: nil, repeats: true)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
let sectionNameLabel : UILabel = {
let sectionNameLabel = UILabel()
sectionNameLabel.font = UIFont(name:"HelveticaNeue-CondensedBlack", size: 36.0)
return sectionNameLabel
}()
lazy var emptyLabel: UILabel = {
let emptyLabel = UILabel()
emptyLabel.text = "Sorry We Currently Have No Events, \n In This Category Near You"
emptyLabel.font = UIFont(name: "Avenir", size: 14)
emptyLabel.numberOfLines = 0
emptyLabel.textAlignment = .center
return emptyLabel
}()
lazy var iconImageView: UIImageView = {
let imageView = UIImageView()
imageView.contentMode = .scaleAspectFit
return imageView
}()
let homeFeedCollectionView: UICollectionView = {
let layout = UICollectionViewFlowLayout()
layout.scrollDirection = .horizontal
let cv = UICollectionView(frame: .zero, collectionViewLayout: layout)
cv.backgroundColor = .clear
return cv
}()
@objc func setupViews(){
backgroundColor = .clear
addSubview(homeFeedCollectionView)
addSubview(sectionNameLabel)
sectionNameLabel.anchor(top: topAnchor, left: leftAnchor, bottom: nil, right: nil, paddingTop: 2, paddingLeft: 4, paddingBottom: 0, paddingRight: 0, width: 0, height: 0)
homeFeedCollectionView.anchor(top: sectionNameLabel.bottomAnchor, left: leftAnchor, bottom: bottomAnchor, right: rightAnchor, paddingTop: 4, paddingLeft: 0, paddingBottom: 0, paddingRight: 0, width: 0, height: 0)
homeFeedCollectionView.delegate = self
homeFeedCollectionView.dataSource = self
homeFeedCollectionView.showsHorizontalScrollIndicator = false
homeFeedCollectionView.register(HomeFeedEventCell.self, forCellWithReuseIdentifier: cellId)
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
guard let currentEventCount = featuredEvents?.count else{
return 0
}
if currentEventCount == 0 {
print("no events")
setupEmptyDataSet()
}else{
emptyView.removeFromSuperview()
}
return currentEventCount
}
@objc func setupEmptyDataSet(){
self.addSubview(emptyView)
emptyView.backgroundColor = .clear
emptyView.snp.makeConstraints { (make) in
make.edges.equalTo(self)
}
emptyView.addSubview(iconImageView)
iconImageView.image = UIImage(named: "icons8-face-100")
iconImageView.snp.makeConstraints { (make) in
make.center.equalTo(emptyView)
}
emptyView.addSubview(emptyLabel)
emptyLabel.snp.makeConstraints { (make) in
make.bottom.equalTo(iconImageView.snp.bottom).offset(30)
make.left.right.equalTo(emptyView)
}
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 20, left: 5, bottom: 20, right: 5)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: frame.width - 40, height: frame.height - 40)
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let eventDetails = EventDetailViewController()
eventDetails.currentEvent = featuredEvents?[indexPath.item]
homeFeedController?.navigationController?.pushViewController(eventDetails, animated: true)
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! HomeFeedEventCell
cell.event = featuredEvents?[indexPath.item]
var rowIndex = indexPath.row
let numberOfRecords = (featuredEvents?.count)! - 1
if rowIndex < numberOfRecords {
rowIndex = rowIndex + 1
}else{
rowIndex = 0
}
scrollTimer = Timer.scheduledTimer(timeInterval: 3.5, target: self, selector: #selector(self.startTimer(theTimer:)), userInfo: rowIndex, repeats: true)
return cell
}
@objc func startTimer(theTimer: Timer){
UIView.animate(withDuration: 1.0, delay: 0, options: .curveEaseOut, animations: {
if let currentIndexPath = self.homeFeedCollectionView.indexPathsForVisibleItems.last{
//Check visible cell is last cell of top collection view then set first index as visible
if currentIndexPath.item == self.homeFeedCollectionView.numberOfItems(inSection: 0)-1{
let nextIndexPath = NSIndexPath(item: 0, section: 0)
//top collection view scroller in first item
self.homeFeedCollectionView.scrollToItem(at: nextIndexPath as IndexPath, at: .right, animated: false)
}else{
//create next index path from current index path of the top collection view
let nextIndexPath = NSIndexPath(item: currentIndexPath.item + 1, section: 0)
//top collection view scroller to next item
self.homeFeedCollectionView.scrollToItem(at: nextIndexPath as IndexPath, at: .left, animated: true)
}
}
}) { (finished) in
if finished {
print("done")
}
}
}
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
self.homeFeedCollectionView.scrollToNearestVisibleCollectionViewCell()
}
func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
if !decelerate {
self.homeFeedCollectionView.scrollToNearestVisibleCollectionViewCell()
}
}
}
老实说，我不确定我做错了什么。但我对这种方法的问题是
当我第一次进入collectionView时，它会直接进入第三项
它有时滚动到某个项目可能是第一个或第三个，然后它就会卡在那里并停止移动。它试图移动，但它一直卡住。
答案 0 :(得分：0)
您有一个viewController用于显示您想要的视图并包含collectionView。该类应该实现UICollectionViewDataSource和UICollectionViewDelegate：
class viewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource
在本课程中，您应该实施numberOfItemsInSection和cellForItemAt方法。
并且你需要在collectionView中使用另一个类：
class customCell: UICollectionViewCell
在这个课程中，您可以定义IBOutlets或者您希望与每个单元格相关的内容 NOT collectionView
最后你应该在viewDidLoad（或viewDidAppear）而不是cellForItemAt代表中启动计时器，
该func调用每一行，然后启动计时器作为collectionView具有的单元格数。
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
scrollTimer = Timer.scheduledTimer(timeInterval: 3.5, target: self, selector: #selector(self.startTimer(theTimer:)), userInfo: rowIndex, repeats: true)
}
答案 1 :(得分：0)
您可以使用此吊舱https://cocoapods.org/pods/AutoScrollCollectionView https://github.com/mohankrishnameruva/AutoScrollCollectionView
从情节提要中的'AutoScrollCollectionView'子类化收藏视图，然后 每当您要开始滚动时，请调用此方法 在collectionView startAutoScrolling（withTimeInterval：TimeInterval（精确地：2.0）！）