swift pass images from collection view controller to another view controller - ios

Question

i have downloaded set of users photo from firebase and view it as collection view (instagram like)
but im trying to enlarge the photo clicked in another view controller using segue but its not working.
Any thoughts about my code:
class ProfileViewController: UIViewController{
var photoThumbnail: UIImage!
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collection_cell", for: indexPath) as! ProfileCollectionViewCell
cell.imageCollection.downloadImage2(from: currPosts[indexPath.row].photoUrl)
cell.imageCollection.image = photoThumbnail
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
performSegue(withIdentifier: "photoViewSegue", sender: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
var destViewController : EnlargePhotoViewController = segue.destination as! EnlargePhotoViewController
destViewController.labelText = "test" //**** this works
destViewController.myImage = photoThumbnail //**** this doesnt work
}
}
and the collection view cell is:
class ProfileCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var imageCollection: UIImageView!
}
lastly the target viewController:
class EnlargePhotoViewController: UIViewController {
#IBOutlet weak var myLabel: UILabel!
#IBOutlet weak var enlargedPhoto: UIImageView!
var labelText = String()
var myImage: UIImage!
override func viewDidLoad() {
super.viewDidLoad()
myLabel.text = labelText
enlargedPhoto.image = myImage
}
}

Answer 1

Try to change to this code:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.cellForItem(at: indexPath) as! ProfileCollectionViewCell
photoThumbnail = cell.imageCollection.image
performSegue(withIdentifier: "photoViewSegue", sender: nil)
}

Answer 2

your only goal is to get the image of the selected cell, this can be done more efficiently. All you have to do is read/write to the cells imageView property, photoThumbnail is never set so always nil, just modify this
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collection_cell", for: indexPath) as! ProfileCollectionViewCell
cell.imageCollection.downloadImage2(from: currPosts[indexPath.row].photoUrl)
//cell.imageCollection.image = photoThumbnail <-- No need of this
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
// get the correct cell on select
if let cell = collectionView.cellForItem(at: indexPath) as! ProfileCollectionViewCell
{
photoThumbnail = cell.imageCollection.image <-- finally assign the imageview to image
performSegue(withIdentifier: "photoViewSegue", sender: self)
}
}
for safer retrieve the image, use like
override func viewDidLoad() {
super.viewDidLoad()
if let getImage = myImage
{
myLabel.text = labelText
enlargedPhoto.image = getImage
}
}

Answer 3

First View Controller
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if indexPath.row == 0
{
let objstory = storyboard?.instantiateViewController(withIdentifier: "SecondViewController") as! SecondViewController
objstory.strd = imageView.image
_ = self.navigationController?.pushViewController(objstory, animated: true)
}
}
SecondViewController
var strd:UIImage!
#IBOutlet weak var imgprof: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
imgprof.image = strd
// Do any additional setup after loading the view.
}

Answer 4

class ProfileViewController: UIViewController{
var photoThumbnail: UIImage!
var selectedPhotoURL: NSUrl!
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collection_cell", for: indexPath) as! ProfileCollectionViewCell
cell.imageCollection.downloadImage2(from: currPosts[indexPath.row].photoUrl)
cell.imageCollection.image = photoThumbnail
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedPhotoURL = currPosts[indexPath.row].photoUrl
performSegue(withIdentifier: "photoViewSegue", sender: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
var destViewController : EnlargePhotoViewController = segue.destination as! EnlargePhotoViewController
destViewController.labelText = "test" //**** this works
//make image from selected url or pass url and download it in EnlargePhotoViewController
let downlodedImage = yourMethodToDownload(selectedPhotoURL)
destViewController.myImage = downlodedImage //**** this will work work
}
}