Perform Segue from UICollectionViewCell Button different from Cell Click - ios

Question

I have a UICollectionViewCell, with a UIButton. And I have two different actions. The first one, when the user presses the cell, it will segue to another view withdidSelectITemAt; the second one, when the users presses the UIButton inside the cell.
My problem is that on Swift Code of MyCollectionViewCell, I cant perform a segue, When I write the Code:
self.performSegue(withIdentifier: "toStoreFromMyDiscounts", sender: nil)
it says the error:
Value of Type MyCollectionViewCell has no member performSegue.
I also cannot write prepareForSegue, it doesn't auto complete.
How can I create a segue from a cell, that is different from click the cell itself?

Answer 1

You can not call performSegue from your UICollectionViewCell subclass, because there is no interface declared on UICollectionViewCell like that.
The reason why it is working didSelectItemAtIndexPath() is because i suppose the delegate of your UICollectionView is a UIViewController subclass, what has the function called performSegueWithIdentifier:()`.
You need to notify your UIViewController when the button was clicked in your UICollectionViewCell, for what you have various possibilities, like KVO or using delegate.
Here is a little code sniplet, how to use KVO. This solution is great, as long as you do not care, in which cell was the button pressed.
import UIKit
class CollectionViewCell: UICollectionViewCell {
#IBOutlet weak var button: UIButton!
}
class CollectionViewController: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!
}
extension CollectionViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell: CollectionViewCell = self.collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! CollectionViewCell
// Add your `UIViewController` subclass, `CollectionViewController`, as the target of the button
// Check out the documentation of addTarget(:) https://developer.apple.com/reference/uikit/uicontrol/1618259-addtarget
cell.button.addTarget(self, action: #selector(buttonTappedInCollectionViewCell), for: .touchUpInside)
return cell
}
func buttonTappedInCollectionViewCell(sender: UIButton) {
self.performSegue(withIdentifier: "toStoreFromMyDiscounts", sender: nil)
}
}
EDIT:
If you care, in which cell the touch event has happend, use the delegate pattern.
import UIKit
protocol CollectionViewCellDelegate: class {
// Declare a delegate function holding a reference to `UICollectionViewCell` instance
func collectionViewCell(_ cell: UICollectionViewCell, buttonTapped: UIButton)
}
class CollectionViewCell: UICollectionViewCell {
#IBOutlet weak var button: UIButton!
// Add a delegate property to your UICollectionViewCell subclass
weak var delegate: CollectionViewCellDelegate?
#IBAction func buttonTapped(sender: UIButton) {
// Add the resposibility of detecting the button touch to the cell, and call the delegate when it is tapped adding `self` as the `UICollectionViewCell`
self.delegate?.collectionViewCell(self, buttonTapped: button)
}
}
class CollectionViewController: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!
}
extension CollectionViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell: CollectionViewCell = self.collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! CollectionViewCell
// Asssign the delegate to the viewController
cell.delegate = self
return cell
}
}
// Make `CollectionViewController` confrom to the delegate
extension CollectionViewController: CollectionViewCellDelegate {
func collectionViewCell(_ cell: UICollectionViewCell, buttonTapped: UIButton) {
// You have the cell where the touch event happend, you can get the indexPath like the below
let indexPath = self.collectionView.indexPath(for: cell)
// Call `performSegue`
self.performSegue(withIdentifier: "toStoreFromMyDiscounts", sender: nil)
}
}

Answer 2

Here's an elegant solution that only requires a few lines of code:
Create a custom UICollectionViewCell subclass
Using storyboards, define an IBAction for the "Touch Up Inside" event of your button
Define a closure
Call the closure from the IBAction
Swift 4+ code
class MyCustomCell: UICollectionViewCell {
static let reuseIdentifier = "MyCustomCell"
#IBAction func onAddToCartPressed(_ sender: Any) {
addButtonTapAction?()
}
var addButtonTapAction : (()->())?
}
Next, implement the logic you want to execute inside the closure in your
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: MyCustomCell.reuseIdentifier, for: indexPath) as? MyCustomCell else {
fatalError("Unexpected Index Path")
}
// Configure the cell
// ...
cell.addButtonTapAction = {
// implement your logic here, e.g. call preformSegue()
self.performSegue(withIdentifier: "your segue", sender: self)
}
return cell
}
You can use this approach also with table view controllers.

Answer 3

Another solution that also works like a charm:
extension YOURViewController : UICollectionViewDataSource
{
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
{
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "YOURCell", for: indexPath) as! YOURCollectionViewCell
cell.butTapped = {
[weak self] (YOURCollectionViewCell) -> Void in
// do your actions when button tapped
}
}
return cell
}
class YOURCollectionViewCell: UICollectionViewCell
{
var butQRTapped: ((YOURCollectionViewCell) -> Void)?
#IBAction func deleteButtonTapped(_ sender: AnyObject) {
butTapped?(self)
}
}