My images take a second to load before they appear, which looks bad. On apps such as instagram, the tableview is hidden until the tableview is loaded... how do they do this? I have a loader that I want to display but don't know when to stop it and show tableview and detect the images have first finished loading? Where do I put stopTimer()?
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MainTableViewCell",
for: indexPath) as! MainTableViewCell
let payment = self.payments[indexPath.row]
cell.profilePicture.layer.cornerRadius = cell.profilePicture.frame.size.width / 2
cell.profilePicture.clipsToBounds = true
if let profileImageUrl = payment.picture {
cell.profilePicture.loadImageUsingCacheWithUrlString(profileImageUrl)
}
if payment.message == "none" {
cell.detailsLabel.text = "No Message"
} else {
cell.detailsLabel.text = "\"\(payment.message ?? "")\""
}
}
MY CODE TO FETCH IMAGE IN TABLEVIEW:
let imageCache = NSCache<NSString, AnyObject>()
extension UIImageView {
func loadImageUsingCacheWithUrlString(_ urlString: String) {
self.image = nil
//check cache for image first
if let cachedImage = imageCache.object(forKey: urlString as NSString) as? UIImage {
self.image = cachedImage
return
}
//otherwise fire off a new download
guard let url = URL(string: urlString) else { return }
URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in
//download hit an error so lets return out
if let error = error {
print(error)
return
}
DispatchQueue.main.async(execute: {
if let downloadedImage = UIImage(data: data!) {
imageCache.setObject(downloadedImage, forKey: urlString as NSString)
self.image = downloadedImage
}
})
}).resume()
}
}
You can simple use SDWebImage with cocoaPods and use it for async image downloader with cache support. Your cell will look like after ad SDWebImage.
import SDWebImage
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MainTableViewCell",
for: indexPath) as! MainTableViewCell
let payment = self.payments[indexPath.row]
cell.profilePicture.layer.cornerRadius = cell.profilePicture.frame.size.width / 2
cell.profilePicture.clipsToBounds = true
if let profileImageUrl = payment.picture {
cell.profilePicture.sd_setImage(with: profileImageUrl, placeholderImage: UIImage(named: "yourPlaceholderImage.png"))
}
if payment.message == "none" {
cell.detailsLabel.text = "No Message"
} else {
cell.detailsLabel.text = "\"\(payment.message ?? "")\""
}
}
There is no need to hide tableView for downloading image.
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