我用json parse编写了collectionView无限滚动的代码。接下来想要每次查看20个数据。打印20data后，我将显示页脚。
现在它将在一段时间内查看所有数据。 Json解析没问题，页脚视图也可以。但问题是无限卷轴根本不起作用。
这是我的所有代码：
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!
}
}
答案 0 :(得分：0)
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]))
}
}