Download image to tableview from Firebase - ios

Question

class ArtistModel {
var id: String?
var name: String?
var genre: String?
var img: String?
init(id: String?, name: String?, genre: String?, img: String?){
self.id = id
self.name = name
self.genre = genre
self.img = img
}
}
and this my tableviewCell
class addArtistTableViewCell: UITableViewCell {
#IBOutlet weak var lblName: UILabel!
#IBOutlet weak var lblGenre: UILabel!
#IBOutlet weak var img: UIImageView!
and this my viewController
import UIKit
import Firebase
import FirebaseDatabase
class addArtistViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var refArtists: FIRDatabaseReference!
#IBOutlet weak var textFieldName: UITextField!
#IBOutlet weak var textFieldGenre: UITextField!
#IBOutlet weak var img: UIImageView!
#IBOutlet weak var labelMessage: UILabel!
#IBOutlet weak var tableViewArtists: UITableView!
//list to store all the artist
var artistList = [ArtistModel]()
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
//getting the selected artist
let artist = artistList[indexPath.row]
//building an alert
let alertController = UIAlertController(title: artist.name, message: "Give new values to update ", preferredStyle: .alert)
//the confirm action taking the inputs
let confirmAction = UIAlertAction(title: "Enter", style: .default) { (_) in
//getting artist id
let id = artist.id
//getting new values
let name = alertController.textFields?[0].text
let genre = alertController.textFields?[1].text
//calling the update method to update artist
self.updateArtist(id: id!, name: name!, genre: genre!)
}
//the cancel action doing nothing
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (_) in }
//adding two textfields to alert
alertController.addTextField { (textField) in
textField.text = artist.name
}
alertController.addTextField { (textField) in
textField.text = artist.genre
}
//adding action
alertController.addAction(confirmAction)
alertController.addAction(cancelAction)
//presenting dialog
present(alertController, animated: true, completion: nil)
}
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
return artistList.count
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
//creating a cell using the custom class
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! addArtistTableViewCell
//the artist object
let artist: ArtistModel
//getting the artist of selected position
artist = artistList[indexPath.row]
//adding values to labels
cell.lblName.text = artist.name
cell.lblGenre.text = artist.genre
//returning cell
return cell
}
#IBAction func buttonAddArtist(_ sender: UIButton) {
addArtist()
}
override func viewDidLoad() {
super.viewDidLoad()
//getting a reference to the node artists
refArtists = FIRDatabase.database().reference().child("artists")
//observing the data changes
refArtists.observe(FIRDataEventType.value, with: { (snapshot) in
//if the reference have some values
if snapshot.childrenCount > 0 {
//clearing the list
self.artistList.removeAll()
//iterating through all the values
for artists in snapshot.children.allObjects as! [FIRDataSnapshot] {
//getting values
let artistObject = artists.value as? [String: AnyObject]
let artistName = artistObject?["artistName"]
let artistId = artistObject?["id"]
let artistGenre = artistObject?["artistGenre"]
let artistImg = artistObject?["artistImg"]
//creating artist object with model and fetched values
let artist = ArtistModel(id: artistId as! String?, name: artistName as! String?, genre: artistGenre as! String?, img: artistImg as! String?)
//appending it to list
self.artistList.append(artist)
}
//reloading the tableview
self.tableViewArtists.reloadData()
}
})
}
func addArtist(){
//generating a new key inside artists node
//and also getting the generated key
let key = refArtists.childByAutoId().key
//creating artist with the given values
let artist = ["id":key,
"artistName": textFieldName.text! as String,
"artistGenre": textFieldGenre.text! as String,
] //as [String : Any]
//adding the artist inside the generated unique key
refArtists.child(key).setValue(artist)
//displaying message
labelMessage.text = "Artist Added"
}
func updateArtist(id:String, name:String, genre:String){
//creating artist with the new given values
let artist = ["id":id,
"artistName": name,
"artistGenre": genre
]
//updating the artist using the key of the artist
refArtists.child(id).setValue(artist)
//displaying message
labelMessage.text = "Artist Updated"
}

Answer 1

First I'd cache the image.
let imageCache = NSCache<AnyObject, AnyObject>()
extension UIImageView {
func loadImageFromCacheWithUrlSting(urlString: String) {
self.image = nil
if let cachedImage = imageCache.object(forKey: urlString as AnyObject) as? UIImage {
self.image = cachedImage
return
}
let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil {
print(error!)
}
DispatchQueue.main.async {
if let downloadedImage = UIImage(data: data!) {
imageCache.setObject(downloadedImage, forKey: urlString as AnyObject)
self.image = downloadedImage
}
}
}.resume()
}
This will save you downloading the image every time the view loads. Then add something like this to cellForRow
if let artistImage = dictionary["img"] as? String {
cell?.artistImageView.loadImageFromCacheWithUrlSting(urlString: artistImage)
}