why table view cells generate before animation - ios

Question

I have an api that I parse and I present the data on my tableview that generates cells . I have make an animation that normally must act before as a present animation for the cells but this did not happen . the result is that the cells appear and suddenly disappear and then appear with the animation .
in the link you can find the gif that I upload the shows what happen .
https://gifyu.com/image/SEGkZ
here is the code :
The OpeningViewController is this :
import UIKit
import ViewAnimator
class OpeningViewController: UIViewController {
//MARK: - IBProperties
#IBOutlet var openingImg: UIImageView!
#IBOutlet var startButton: UIButton!
//MARK: - Properties
var nft : Nft?
//MARK: - Life Cyrcle
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let animation = AnimationType.from(direction: .top, offset: 50)
openingImg.animate(animations: [animation] , delay: 0.3, duration: 2)
openingImg.layer.shadowColor = UIColor.black.cgColor
openingImg.layer.shadowOffset = CGSize(width: 0, height: 0)
openingImg.layer.shadowOpacity = 0.65
openingImg.layer.shadowRadius = 10
}
//MARK: - Methods
#IBAction func startApp(_ sender: Any) {
HapticsManager.shared.selectionVibrate()
let storyBoard = UIStoryboard(name: "Lobby", bundle: nil)
let controller = storyBoard.instantiateViewController(withIdentifier: "LobbyViewController") as! LobbyViewController
controller.modalTransitionStyle = .flipHorizontal
self.navigationController?.pushViewController(controller, animated: true)
}
}
The presentation happens in LobbyViewController :
import UIKit
import ViewAnimator
class LobbyViewController: UIViewController {
// MARK: - IBProperties
#IBOutlet weak var tableView: UITableView!
// MARK: - Properties
var data: [DataEnum] = []
var likes:[Int] = []
var numlikes: Int = 0
var nfts: [Nft] = []
let creators : [Creator] = []
var icons: [Icon] = []
var loadData = APICaller()
// MARK: - Life Cyrcle
override func viewDidLoad() {
super.viewDidLoad()
let nib = UINib(nibName: "AssetTableViewCell", bundle: nil)
tableView.register(nib, forCellReuseIdentifier: "AssetTableViewCell")
let nib2 = UINib(nibName: "CreatorsTableViewCell", bundle: nil)
tableView.register(nib2, forCellReuseIdentifier: "CreatorsTableViewCell")
tableView.dataSource = self //method to generate cells,header and footer before they are displaying
tableView.delegate = self //method to provide information about these cells, header and footer ....
downloadJSON {
self.tableView.reloadData()
print("success")
}
loadData.downloadData { (result) in
print(result)
}
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
let animation = AnimationType.from(direction: .top, offset: 300)
UIView.animate(views: tableView.visibleCells,
animations: [animation], delay: 1, duration: 2)
}
//stelnei ta dedomena apo to kathe row ston PresentViewController
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destination = segue.destination as? PresentViewController {
if tableView.cellForRow(at: tableView.indexPathForSelectedRow!) is AssetTableViewCell {
destination.nft = nfts[tableView.indexPathForSelectedRow!.row-1]
destination.delegate = self
} else {
//add alert action
let alert = UIAlertController(title: "Invalid Touch", message: "You press wrong row. Choose one of the following list.", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
present(alert, animated: true, completion: {
return
})
}
}
}
// MARK: - Methods
func downloadJSON(completed: #escaping () -> ()) {
let url = URL(string: "https://public.arx.net/~chris2/nfts.json")
URLSession.shared.dataTask(with: url!) { [self] data, response, error in
if error == nil {
do {
self.nfts = try JSONDecoder().decode([Nft].self, from: data!)
let creators = nfts.map { nft in
nft.creator
}
self.data.append(.type1(creators: creators))
self.nfts.forEach { nft in
self.data.append(.type2(nft: nft))
}
DispatchQueue.main.async {
completed()
}
}
catch {
print("error fetching data from api")
}
}
}.resume()
}
}
// MARK: - Extensions
extension LobbyViewController : UITableViewDelegate , UITableViewDataSource {
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data.count
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
indexPath.row == 0 ? 100 : UITableView.automaticDimension
}
//gemizo ta rows tou table
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
switch self.data[indexPath.item] {
case .type1(let creators):
print("--->", creators)
let cell = tableView.dequeueReusableCell(withIdentifier: "CreatorsTableViewCell",
for: indexPath) as! CreatorsTableViewCell
cell.layer.cornerRadius = 15
cell.layer.shadowColor = UIColor.black.cgColor
cell.layer.shadowOffset = CGSize(width: 0, height: 0)
cell.layer.shadowOpacity = 0.8
cell.layer.shadowRadius = 15
cell.layer.cornerRadius = cell.frame.height/2
cell.updateCreators(creators)
return cell
case .type2(let nft):
let cell = tableView.dequeueReusableCell(withIdentifier: "AssetTableViewCell",
for: indexPath) as! AssetTableViewCell
cell.nameLabel?.text = nft.name
cell.nameLabel.layer.cornerRadius = cell.nameLabel.frame.height/2
cell.likesLabel?.text = "\((numlikes))"
let imgUrl = (nft.image_url)
print(imgUrl)
cell.iconView.downloaded(from: imgUrl)
cell.iconView.layer.cornerRadius = cell.iconView.frame.height/2
return cell
}
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
performSegue(withIdentifier: "showDetails", sender: self)
}
}
extension LobbyViewController : TestDelegate{
func sendBackTheLikess(int: Int) {
numlikes = int
tableView.reloadData()
}
}
// MARK: - Enums
enum DataEnum {
case type1(creators: [Creator])
case type2(nft: Nft)
}
// MARK: - Struct
struct Constants {
static let url = "https://public.arx.net/~chris2/nfts.json"
}
The APICaller :
import Foundation
final class APICaller {
static let shared = APICaller()
public struct Constants {
static let url = "https://public.arx.net/~chris2/nfts.json"
}
public func downloadData(completion:#escaping (Result<[Nft], Error>) -> Void )
{
guard let url = URL(string:Constants.url)else{
return
}
let task = URLSession.shared.dataTask(with: url) { data, response, error in
//print(response)
print("here")
guard let data = data , error == nil else{
print("something went wrong with data")
return
}
print("here4")
//mexri edo exoume parei ta data kai tora me to do-catch tha ta kanoume convert se object
do{
//Decode the response
let nfts = try JSONDecoder().decode([Nft].self, from: data)
completion(.success(nfts))
print(nfts)
}catch{
completion(.failure(error))
}
}
task.resume()
}
}

Answer 1

Just move your animation from viewDidAppear(animated:) to tableView(_:willDisplay:forRowAt:) and call for each cell separately. Also don’t forget not to call this animation once it finished.