CollectionView Jsonの解析でSwiftの無限のスクロール

Question

json parseを使用してcollectionView無限スクロールのコードを作成しました。次に、毎回20のデータを表示したい。 20dataを印刷した後、私はフッターを表示します。

これで、すべてのデータを一度に表示します。 Jsonの解析はOKですが、フッタービューもOKです。しかし、問題は無限である - スクロールはまったく動かない。ここで

私のすべてのコードです：

import Foundation 

import UIKit 


enum LoadMoreStatus{ 

    case loading 
    case finished 
    case haveMore 
} 

class Product: NSObject { 

    var id: Int? 
    var category_id: Int? 
    var image: String? 
    var name: String? 
    var ar_name: String? 

    var ar_description: String? 
    var price: NSNumber? 
    var quantity: String? 
    var is_featured: String? 
    var seller_id: String? 
    var payment_required: String? 
    var is_editors_choice: String? 
    var created_at: String? 
    var updated_at: String? 

} 


let categoryCellid = "categoryCellid" 

class ProductByCategoryCollectionView: UICollectionViewController, UICollectionViewDelegateFlowLayout { 



    var headercellId = "headercellId" 

    var footerCellid = "firstfootercellid" 
    var numberOfCells = 5 
    var loadingStatus = LoadMoreStatus.haveMore 


    var arrProduct = [Product]() 
    var category_id:Int = 0; 
    var product_count:Int = 0; 

    func reloadData(){ 

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

    func loadMore() { 

     if numberOfCells >= arrProduct.count{ // here will show untill 22 
      loadingStatus = .finished 
      collectionView?.reloadData() 
      return 
     } 



     Timer.schedule(delay: 2) { timer in 
      self.numberOfCells += 10 
      self.collectionView?.reloadData() 
     } 
    } 

    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) 

     collectionView?.register(ProductByCategoryFooterCell.self, forSupplementaryViewOfKind: UICollectionElementKindSectionFooter, withReuseIdentifier: footerCellid) 

    } 


    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() 

    } 



    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 arrProduct.count 

    } 

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


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



     let cell = collectionView.dequeueReusableCell(withReuseIdentifier: categoryCellid, for: indexPath) as! ProductByCategoryCollectionViewCell 
     cell.callProductObject4Cell = arrProduct[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 = UICollectionViewController(collectionViewLayout: layout) 
     navigationController?.pushViewController(controller1, animated: true) 

    } 
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) { 
     super.viewWillTransition(to: size, with: coordinator) 

     collectionView?.collectionViewLayout.invalidateLayout() 
    } 


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


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

     } 

     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 ProductByCategoryCollectionViewCell: UICollectionViewCell { 

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



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



class ProductByCategoryFooterCell: 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) 



     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! 
    } 
} 

Answer 1

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])) 
    } 
}