UITableView not visible until tapped on screen - ios

Question

I am new to swift,
I am working on an application
I Have 2 different API to get banner data and tableView Data, for the Images I am getting URL from server .
After the Banner is loaded and running I am populating the UITableView,
problem is either the UITableView visible after sometime (around 1 min) or I have to tap on the screen to make it visible
Also the banner is not scrolling properly when I switch between screens.
Can someone review the code and help me whats wrong.
Here is what I have done so far
Controller Code
class CompanyViewController: UIViewController,IndicatorInfoProvider {
#IBOutlet weak var tableView: UITableView!
#IBOutlet weak var sliderCollectionView: UICollectionView!
#IBOutlet weak var pageView: UIPageControl!
var activityIndicator: UIActivityIndicatorView=UIActivityIndicatorView()
var imgArr = [UIImage(named: "LoginHeader")]
var imgArrTemp = [String]()
var sectionHeaderName = [String]()
var imageArray = [[String]]()
var sectionImage = [String]()
var timer = Timer()
var counter = 0
override func viewDidLoad() {
super.viewDidLoad()
pageView.numberOfPages = imgArr.count
pageView.currentPage = 0
tableView.delegate = self
tableView.dataSource = self
tableView.estimatedRowHeight = 120
tableView.tableFooterView = UIView()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
self.getBannerData()
DispatchQueue.main.async() {
self.getCenterData()
self.tableView.reloadData()
}
}
func indicatorInfo(for pagerTabStripController: PagerTabStripViewController) -> IndicatorInfo {
return IndicatorInfo(title: "COMPANY")
}
#objc func changeImage() {
if counter < imgArr.count {
let index = IndexPath.init(item: counter, section: 0)
self.sliderCollectionView.scrollToItem(at: index, at: .centeredHorizontally, animated: true)
pageView.currentPage = counter
counter += 1
} else {
counter = 0
let index = IndexPath.init(item: counter, section: 0)
self.sliderCollectionView.scrollToItem(at: index, at: .centeredHorizontally, animated: true)
pageView.currentPage = counter
counter = 1
}
}
func getCenterData(){
let appId = LocalStorage.getStringDataFromLocalStorage(key:Constants.APPID)
let token = "Bearer "+LocalStorage.getStringDataFromLocalStorage(key: Constants.TOKEN)
if let url = URL(string: Constants.EXPERIENCE_CENTER+appId){
var request = URLRequest(url: url)
request.httpMethod = "GET"
request.setValue(token, forHTTPHeaderField:"Authorization")
APIManager.sharedInstance.getCall(request: request){
(data) in
if(!data.isEmpty){
do{
let _object = try JSONDecoder().decode(ExperienceCenterModel.self, from: Data(data.utf8))
let data = try JSONEncoder().encode(_object.practice)
let jsonString = String(data: data, encoding: .utf8)!
LocalStorage.saveStringDataInLocalStorage(key: Constants.PRACTICE, value: jsonString)
let technology = try JSONEncoder().encode(_object.technology)
let technologyJsonString = String(data: technology, encoding: .utf8)!
LocalStorage.saveStringDataInLocalStorage(key: Constants.TECTNOLOGY, value: technologyJsonString)
for sectionHeader in _object.practice.data{
self.sectionHeaderName.insert(sectionHeader.practiceName!, at: self.sectionHeaderName.count)
self.sectionImage.removeAll()
for images in sectionHeader.experience{
let url = images.experienceImage.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
self.sectionImage.insert(url!, at: self.sectionImage.count)
}
self.imageArray.insert(self.sectionImage, at: self.imageArray.count)
}
self.tableView.reloadData()
}catch{
let nsError = error as NSError
print(nsError.localizedDescription)
}
}
}
}
}
func getBannerData(){
let defaults = UserDefaults.standard
let appId = defaults.string(forKey: Constants.APPID)
let token = "Bearer "+defaults.string(forKey: Constants.TOKEN)!
if let url = URL(string: Constants.EXPERIENCE_BANNER_CENTER+appId!){
var request = URLRequest(url: url)
request.httpMethod = "GET"
request.setValue(token, forHTTPHeaderField:"Authorization")
APIManager.sharedInstance.getCall(request: request){
(data) in
if(!data.isEmpty){
do{
let _object = try JSONDecoder().decode(SliderModel.self, from: Data(data.utf8))
self.imgArr.removeAll()
for images in _object.data{
let url = images.experience_image.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
let imageUrlString = url
let imageUrl:URL = URL(string: imageUrlString!)!
// self.imgArrTemp.insert(url!, at: self.imgArrTemp.count)
// self.pageView.numberOfPages = self.imgArrTemp.count
DispatchQueue.main.async() {
let imageData:NSData = NSData(contentsOf: imageUrl)!
self.imgArr.insert(UIImage(data: imageData as Data), at: self.imgArr.count)
self.pageView.numberOfPages = self.imgArr.count
}
}
self.stopActivityIndicator()
}
catch{
self.stopActivityIndicator()
self.showAlertMessage(alertMessage: Constants.COMMON_ERROR)
}
DispatchQueue.main.async {
self.timer = Timer.scheduledTimer(timeInterval: 2.0, target: self, selector: #selector(self.changeImage), userInfo: nil, repeats: true)
}
}
}
}
}
func startActivityIndicator(){
activityIndicator.center = CGPoint(x: 180, y: -40)
activityIndicator.hidesWhenStopped = true
activityIndicator.style = UIActivityIndicatorView.Style.gray
view.addSubview(activityIndicator)
activityIndicator.startAnimating()
UIApplication.shared.beginIgnoringInteractionEvents()
}
func stopActivityIndicator(){
activityIndicator.stopAnimating()
UIApplication.shared.endIgnoringInteractionEvents()
}
func showAlertMessage(alertMessage:String){
self.stopActivityIndicator()
let alert = UIAlertController(title: "Alert", message: alertMessage, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { action in
switch action.style{
case .default:
print("default")
case .cancel:
print("cancel")
case .destructive:
print("destructive")
}}))
self.present(alert, animated: true, completion: nil)
}
}
extension CompanyViewController: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
if(self.imgArr.count > 0){
if let vc = cell.viewWithTag(111) as? UIImageView {
if(self.imgArr.count == indexPath.row){
vc.image = self.imgArr[indexPath.row-1]
}else{
vc.image = self.imgArr[indexPath.row]
}
}
}
return cell
}
}
extension CompanyViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let size = sliderCollectionView.frame.size
return CGSize(width: size.width, height: size.height)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 0.0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0.0
}
}
extension CompanyViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
if self.sectionHeaderName.count>0 {
return self.sectionHeaderName[section]
}else{
return ""
}
}
//NUMBER OF SECTION WE WANT IN A TABLE
func numberOfSections(in tableView: UITableView) -> Int {
return self.sectionHeaderName.count
}
/*NUMNBER OF ROWS IN A SECTION*/
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 130
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCell(withIdentifier: "tableViewCell", for: indexPath) as? TableViewCell else {fatalError("Unable to create table view cell")}
cell.cellDataURI = self.imageArray[indexPath.section]
cell.collectionView.reloadData()
return cell
}
}
Code for Table View Cell
class TableViewCell: UITableViewCell, UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
var cellData = [UIImage]()
var cellDataURI = [String]()
lazy var imageCache: NSCache<NSString,UIImage> = {
return NSCache<NSString,UIImage>.init()
}()
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return self.cellDataURI.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionCell", for: indexPath) as? CollectionViewCell
let url = cellDataURI[indexPath.row]
guard let image = self.imageCache.object(forKey: NSString(string: url))else{
return loadImage(url: URL(string: url)!, cell: cell!, indexPath: indexPath)
}
cell?.imageView.image = image//cellDataURI[indexPath.row]
return cell!
}
func loadImage(url: URL,cell: CollectionViewCell, indexPath: IndexPath) -> CollectionViewCell{
URLSession.shared.dataTask(with: url){
(rawData, _, _) in
guard let data = rawData else { return }
guard let image = UIImage.init(data: data) else{
return
}
self.imageCache.setObject(image, forKey: NSString(string: url.absoluteString) )
DispatchQueue.main.async {
guard let visCell = self.collectionView.cellForItem(at: indexPath) as? CollectionViewCell else{ return }
visCell.imageView.image = image
}
}.resume()
return cell
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize{
let size = CGSize(width: 150, height: 300)
return size
}
#IBOutlet weak var collectionView: UICollectionView!
override func awakeFromNib() {
super.awakeFromNib()
self.collectionView.delegate = self
self.collectionView.dataSource = self
}
}
Any help would be appreciated

Answer 1

You can use dispatch group to run multiple apis and get notification when all tasks are completed. Then reload tableview
let dispatchGroup = DispatchGroup()
dispatchGroup.enter()
firstApiCall(completion:{
dispatchGroup.leave()
})
dispatchGroup.enter()
secondApiCall(completion:{
dispatchGroup.leave()
})
dispatchGroup.notify(queue: .main) {[weak self] in
print("All Data fetched")
self?.tableView.reloadData()
}