How to use the button inside CollcetionViewCell to delete cell itself - ios

Question

My app use flickr Api to search photo and present by collectionView.
Also I want to add the photo that i want to favorite.
So I add the button on cell and use Coredata to save image and photo title.
#IBAction func saveBtn(_ sender: UIButton) {
checkFavorite(photoTitle: photoArrayFromSearchView[sender.tag].title)
if isAdded == false {
save(btnTag: sender.tag)
}
}
func save(btnTag:Int){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
let favoritePhotos = FavoritePhotos(context: context)
downloadFavoriteData(btnTag: btnTag, favoritePhotos: favoritePhotos) { (dataDownloaded) in
if dataDownloaded {
do {
try context.save()
print("save successfully")
} catch {
print("fail to save")
}
}
}
}
I cant find the way to press button to save relative photo so i use button.tag = cell.item to achieve.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath) as! ResultCollectionViewCell
cell.BtnView.tag = indexPath.item
cell.photoTitle.text = photoArrayFromSearchView[indexPath.row].title
cell.photoImg.af_setImage(withURL: photoArrayFromSearchView[indexPath.row].photoURL)
return cell }
It works but here is the problem.
I cant use the same way by button.tag to delete item.
When the item has been delete, somehow my button.tag won't reload.
And it crash. Error: Index out of range.
Because button.tag didn't reload but collectionView index is already change.
#IBAction func deleteBtn(_ sender: UIButton) {
let Index = IndexPath(row: sender.tag, section: 0)
deleteItem(btnTag: sender.tag)
fetch()
favoritePhotoCollection.deleteItems(at: [Index])
}
func deleteItem(btnTag:Int){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
context.delete(favoriteArray[btnTag])
do {
try context.save()
} catch {
print("delete fail")
}
}
func fetch(){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let context = appDelegate.persistentContainer.viewContext
let fetchRequset = NSFetchRequest<FavoritePhotos>(entityName: "FavoritePhotos")
fetchRequset.returnsObjectsAsFaults = false
do {
favoriteArray = try context.fetch(fetchRequset)
} catch {
print("fail to fetch")
}
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return favoriteArray.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath) as!
FavoriteCollectionViewCell
cell.BtnView.tag = indexPath.item
cell.photoTitle.text = favoriteArray[indexPath.row].photoTitle
if let data = favoriteArray[indexPath.row].photoImg as Data? {
cell.photoImg.image = UIImage(data: data)
}else {
cell.photoImg.image = nil
}
return cell
}
Can someone tell me how to fix this problem?
Or the better way to achieve using button inside CollcetionViewCell to delete or save data.
thx your patience to read.

Answer 1

It will not work because as collection view recycle. So that tag wouldn't be the same. What you can do is assigning something which is unique like you can use save title as a tag and try to save and extract using that tag.

Answer 2

The problem is the fetch line. Remove the item from CoreData and from the data source array but don't refetch the data.
#IBAction func deleteBtn(_ sender: UIButton) {
let indexPath = IndexPath(row: sender.tag, section: 0)
photoArrayFromSearchView.remove(at: indexPath.row)
deleteItem(btnTag: sender.tag)
favoritePhotoCollection.deleteItems(at: [indexPath])
}
There is another inconsistency: There are two different arrays favoriteArray and photoArrayFromSearchView

Answer 3

Instead of the button.tag, you could make a delete action delegate protocol(that has deleteCell func). Your view controller should conform the protocol and assign self to the cells. Then view controller can figure out the item's indexPath by "collectionView.indexPath(for :UICollectionViewCell)" and then delete the cell in the implementation of deleteCell func.