Swift 中的 CollectionView 无限滚动与 Json 解析
CollectionView infinite scroll in Swift with Json parse
我用 json 解析编写了 collectionView 无限滚动的代码。接下来每次要查看20条数据。打印 20 数据后，我将显示页脚。
现在要一次查看所有数据。 Json 解析正常，页脚视图也正常。但问题是无限滚动根本不起作用。
这是我的全部代码：
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!
}
}
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]))
}
}
我用 json 解析编写了 collectionView 无限滚动的代码。接下来每次要查看20条数据。打印 20 数据后，我将显示页脚。
现在要一次查看所有数据。 Json 解析正常，页脚视图也正常。但问题是无限滚动根本不起作用。
这是我的全部代码：
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!
}
}
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]))
}
}