Défilement infini dans collectionView par programmation

Question

Je veux faire défiler 10 images infinies dans collectionView par programme de swift. l'image est venue de web par json selon mon choix. J'ai été incapable de faire défiler 20 images dans une fois. ici est mon code

import Foundation 


import UIKit 

let categoryCellid = "categoryCellid" 


class ProductByCategoryCollectionView: UICollectionViewController, UICollectionViewDelegateFlowLayout { 

    var headercellId = "headercellId" 


    var callCategoryObject = [Product]() 


    func getPropductListByCategory(){ 

     // has api code, that was well 
    } 




    override func viewDidLoad() { 
     super.viewDidLoad() 



     self.getPropductListByCategory() 


     collectionView?.backgroundColor = .white 

     navigationItem.title = "Product" 
     navigationItem.backBarButtonItem = UIBarButtonItem(title: "Back", style: .plain, target: nil, action: nil) 
     navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Sort By", style: .plain, target: nil, action: nil) 



     self.setupHeaderView() 

     collectionView?.register(ProductByCategoryCollectionViewCell.self, forCellWithReuseIdentifier: categoryCellid) 
    } 



    func showCategoryDetailSegue() { 

     let detailcontroller = UIViewController() 
     navigationController?.pushViewController(detailcontroller, animated: true) 
    } 



    func sortBtnTarget() { 

    } 



    func filterBtnTarget() { 

    } 

    let dividedLine: UIView = { 
     let view = UIView() 

     view.backgroundColor = UIColor(white: 0.4, alpha: 0.4) 
     return view 

    }() 

    let totalItemLabel: UILabel = { 
     let label = UILabel() 

     label.text = "" 
     label.textAlignment = .center 
     label.font = UIFont.systemFont(ofSize: 15) 
     label.backgroundColor = UIColor.white 

     return label 
    }() 



    let dividerLineView: UIView = { 
     let view = UIView() 
     view.backgroundColor = UIColor.white 

     return view 
    }() 



    func setupHeaderView(){ 


     view.backgroundColor = UIColor(white: 0.4, alpha: 0.4) 


     dividedLine.frame = CGRect(x: 0, y: 95, width: view.frame.width, height: 1) 
     totalItemLabel.frame = CGRect(x: 0, y: 55, width: view.frame.width, height: 40) 

     view.addSubview(totalItemLabel) 

     view.addSubview(dividedLine) 





    } 



    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { 


     return callCategoryObject.count 
    } 

    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { 


     let cell = collectionView.dequeueReusableCell(withReuseIdentifier: categoryCellid, for: indexPath) as! ProductByCategoryCollectionViewCell 
     cell.callProductObject4Cell = callCategoryObject[indexPath.item] 



     return cell 
    } 

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { 
     return CGSize(width: 172, height: 300) 
    } 

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets { 
     return UIEdgeInsetsMake(32, 10, 0, 10) 
    } 

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat { 
     return 0 
    } 

    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) { 


     let layout = UICollectionViewFlowLayout() 
     layout.scrollDirection = .horizontal 
     let controller1 = DetailsController(collectionViewLayout: layout) 
     navigationController?.pushViewController(controller1, animated: true) 

    } 

} 

class ProductByCategoryCollectionViewCell: UICollectionViewCell { 

    var callProductObject4Cell: Product? { 
     didSet { 
      productLabel.text = callProductObject4Cell?.name 

      // priceLabel.text = String(describing: callProductObject4Cell?.price) 

      if let price = callProductObject4Cell?.price { 
       priceLabel.text = "$\(price)" 
      } else { 
       priceLabel.text = "" 
      } 




      if let profileImageUrl = callProductObject4Cell?.image { 
       productImage.loadImageUsingUrlString(profileImageUrl) 
      } 


     } 
    } 

    override init(frame: CGRect) { 
     super.init(frame: frame) 
     setupcategoryCell() 
    } 

    required init?(coder aDecoder: NSCoder) { 
     fatalError("init(coder:) has not been implemented") 
    } 

    let productImage: UIImageView = { 
     let image = UIImageView() 

     image.image = UIImage(named: "default") 
     image.contentMode = .scaleAspectFit 
     image.layer.borderWidth = 1 
     image.layer.borderColor = UIColor.orange.cgColor 
     image.layer.masksToBounds = true 
     return image 
    }() 

    let productLabel: UILabel = { 
     let label = UILabel() 
     label.text = "productName" 
     label.textColor = .black 
     label.numberOfLines = 0 
     label.font = UIFont.boldSystemFont(ofSize: 10) 

     return label 
    }() 

    let priceLabel: UILabel = { 
     let label = UILabel() 
     //  label.backgroundColor = .lightGray 
     label.text = "" 
     label.textColor = .orange 
     label.font = UIFont.systemFont(ofSize: 13) 

     return label 
    }() 

    func setupcategoryCell() { 

     addSubview(productImage) 
     addSubview(productLabel) 
     addSubview(priceLabel) 

     addConstraintsWithFormat("H:|[v0]|", views: productImage) 
     addConstraintsWithFormat("V:|[v0(230)]-2-[v1][v2(10)]-5-|", views: productImage,productLabel, priceLabel) 

     addConstraintsWithFormat("H:|[v0]|", views: productLabel) 

     addConstraintsWithFormat("H:|[v0]|", views: priceLabel) 
    } 
} 

Answer 1

Utilisez ce code pour un UIScrollView infini:

import Foundation 
import UIKit 

enum LoadMoreStatus { 
    case loading 
    case finished 
    case haveMore 
} 

class ViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout { 

    var verticalDataSource = [String]() 

    var firstCellid = "firstcellid" 
    var firstFooterCellid = "firstfootercellid" 
    var numberOfCells = 5 
    var loadingStatus = LoadMoreStatus.haveMore 

    func reloadData() { 
     //numberOfCells = 10 
     collectionView?.reloadData() 
     if numberOfCells > 0 { 
      collectionView?.scrollToItem(at: IndexPath(row: 0, section: 0), at: .left, animated: true) 
     } 
    } 

    func loadMore() { 
     if numberOfCells >= 40 { 
      // here will show untill finished number 
      loadingStatus = .finished 
      collectionView?.reloadData() 
      return 
     } 

     // Replace code with web service and append to data source 
     Timer.schedule(delay: 2) { timer in 
      self.numberOfCells += 2 
      self.collectionView?.reloadData() 
     } 
    } 

    override func viewDidLoad() { 
     super.viewDidLoad() 

     self.automaticallyAdjustsScrollViewInsets = false 

     collectionView?.register(VerticalCollectionViewCell.self, forCellWithReuseIdentifier: firstCellid) 
     collectionView?.register(VerticalCollectionViewCell2.self, forSupplementaryViewOfKind: UICollectionElementKindSectionFooter, withReuseIdentifier: firstFooterCellid) 
    } 

    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
     // Dispose of any resources that can be recreated. 
    } 

    //MARK - Rotation methods 

    override func didRotate(from fromInterfaceOrientation: UIInterfaceOrientation) { 
     var text="" 

     switch UIDevice.current.orientation { 
     case .portrait: 
      text="Portrait" 
     case .portraitUpsideDown: 
      text="PortraitUpsideDown" 
     case .landscapeLeft: 
      text="LandscapeLeft" 
     case .landscapeRight: 
      text="LandscapeRight" 
     default: 
      text="Another" 
     } 

     NSLog("You have moved: \(text)") 

     collectionView?.reloadData() 
    } 

    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int { 
     return numberOfCells 
    } 

    // The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath: 
    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell { 

     if(indexPath.row==numberOfCells-1) { 
      if loadingStatus == .haveMore { 
       self.perform(#selector(ViewController.loadMore), with: nil, afterDelay: 0) 
      } 
     }  

     let cell = collectionView.dequeueReusableCell(withReuseIdentifier: firstCellid, for: indexPath) as! VerticalCollectionViewCell 
     cell.menuHeaderLabel.text = "Labet text no \(indexPath.item)" 
     return cell 

    } 

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { 
     return CGSize(width: self.view.frame.width, height: 100) 
    } 

    override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView { 
     var footerView:VerticalCollectionViewCell2! 

     if (kind == UICollectionElementKindSectionFooter) && (loadingStatus != .finished) { 
      footerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: firstFooterCellid, for: indexPath) as! VerticalCollectionViewCell2 
     } 

     return footerView 
    } 

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize { 
     return (loadingStatus == .finished) ? CGSize.zero : CGSize(width: self.view.frame.width, height: 50) 
    }   
} 

class VerticalCollectionViewCell: UICollectionViewCell { 

    override init(frame: CGRect) { 
     super.init(frame: frame) 

     setupCell() 
    } 

    required init?(coder aDecoder: NSCoder) { 
     fatalError("init(coder:) has not been implemented") 
    } 

    let menuHeaderLabel: UILabel = { 
     let label = UILabel() 
     label.text = "lable text" 
     label.textColor = .orange 
     label.textAlignment = .center 
     label.font = UIFont.boldSystemFont(ofSize: 15) 
     label.translatesAutoresizingMaskIntoConstraints = false 

     return label 
    }() 

    func setupCell() { 
     addSubview(menuHeaderLabel) 

     // addTaskButton.addTarget(self, action: #selector(MenuHeader.addTask), for: .touchUpInside) 

     addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-8-[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": menuHeaderLabel])) 

     addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-5-[v0(30)]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": menuHeaderLabel])) 
    } 
} 

class VerticalCollectionViewCell2: UICollectionViewCell { 
    override init(frame: CGRect) { 
     super.init(frame: frame) 
     backgroundColor = .white 
     setupCell() 
    } 

    required init?(coder aDecoder: NSCoder) { 
     fatalError("init(coder:) has not been implemented") 
    } 

    let menuHeaderLabel: UILabel = { 
     let label = UILabel() 
     label.text = "loadin more waiting" 
     label.textColor = .green 
     label.textAlignment = .center 
     label.font = UIFont.boldSystemFont(ofSize: 15) 
     label.translatesAutoresizingMaskIntoConstraints = false 
     return label 
    }() 

    func setupCell() { 
     addSubview(menuHeaderLabel) 

     // addTaskButton.addTarget(self, action: #selector(MenuHeader.addTask), for: .touchUpInside) 

     addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-8-[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": menuHeaderLabel])) 

     addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-5-[v0(30)]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": menuHeaderLabel])) 
    } 
} 

extension Timer { 
    class func schedule(delay: TimeInterval, handler: @escaping (Timer!) -> Void) -> Timer { 
     let fireDate = delay + CFAbsoluteTimeGetCurrent() 
     let timer = CFRunLoopTimerCreateWithHandler(kCFAllocatorDefault, fireDate, 0, 0, 0, handler) 
     CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, CFRunLoopMode.commonModes) 
     return timer! 
    } 

    class func schedule(repeatInterval interval: TimeInterval, handler: @escaping (Timer!) -> Void) -> Timer { 
     let fireDate = interval + CFAbsoluteTimeGetCurrent() 
     let timer = CFRunLoopTimerCreateWithHandler(kCFAllocatorDefault, fireDate, interval, 0, 0, handler) 
     CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, CFRunLoopMode.commonModes) 
     return timer! 
    } 
}