UICollectionView didSelectItemAt 未被调用

Question

I am puzzled because It is just a simple thing but doesn't work.

This is my checked list before write question at here.

1. UICollectionViewDelegate is registered

2. There is nothing on above than UICollectionView from "Debug View Hierarchy"

3. isUserInteractionEnabled of UICollectionView and UICollectionViewCell is true

4. isAllowsSelection of UICollectionView is true

Is there anything else I should check out?

=====

class MyView: NibDesignable { // It's UIView with NibDesignableProtocol (https://github.com/mbogh/NibDesignable)
    @IBOutlet weak var collectionView: UICollectionView!

    override init(frame: CGRect) {
        super.init(frame: frame)

        self.setup()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        self.setup()
    }

    private func setup() {
        print("test - It's called.")

        self.collectionView.dataSource = self
        self.collectionView.delegate = self
        self.collectionView.isUserInteractionEnabled = true
        self.collectionView.isAllowsSelection = true
    }
}

extension MyView: UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath {
        print("test - It's not called")
    }
}

I pasted only the part relating to question because all of code is too long.

Answer 1

This can happen if you have a gestureRecognizer in your custom cell. this will override the didSelectItemAt delegate of the collectionView.

If this is your issue, then you can resolve it by identifying the gestureRecognizer and doing the following:

let tap = UITapGestureRecognizer(target: self, action: #selector(self.someViewInMyCellTapped(_:)))
someViewInMyCell.addGestureRecognizer(tap)

tap.cancelsTouchesInView = false

Answer 2

isUserInteractionEnabled在MyView本身或其任何父项上可能为 false。

Answer 3

If anyone's experiencing same issue as me with Simulator XR try out other simulators. My didSelectItemAt method was never being called for some indexes when using XR simulator and index were random everytime I relaunched the simulator. Using iPhone 6s simulator made it go away

Answer 4

I changed the isUserInteractionEnabled property of the subviews of Cell to false . and it works.

Answer 5

确保单元格是UICollectionViewCell的子类，而不是UICollectionViewReusableView 。

Answer 6

For me the problem was in Keyboard extension on My BaseViewController

extension NewBaseVC: UITextFieldDelegate {

    func initializeHideKeyboard(){
        let tap: UITapGestureRecognizer = UITapGestureRecognizer(
            target: self,
            action: #selector(dismissMyKeyboard))

        view.addGestureRecognizer(tap)
    }

    @objc func dismissMyKeyboard(){
        view.endEditing(true)
    }
}

When I called the initializeKeyboard() , the TapRecognizer was fired. And the tap recognizer was overlapping with my collection view didSelectItemEvent.

Answer 7

Try setting delegate inside

func awakeFromNib(){
 super.awakeFromNib()
 self.collectionView.dataSource = self
 self.collectionView.delegate = self } 

Answer 8

In my case there was a problem with custom UITapGestureRecognizer . Despite the fact that the scroll and highlight worked for the collection, there was no cell selection. I had to use cancelsTouchesInView property of the recognizer.

let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(myAction(_:)))
tapGestureRecognizer.cancelsTouchesInView = false // <- this helped

Also worth to check your collection view cell frame after screen loaded and views layout finished.

Answer 9

In my case, it's because collectionView keep crazy reloading.

collectionView.reloadData

Only after end reload then I can interact with it.

Answer 10

Also check parent view for UITapGestureRecognizer .

In my case UITapGestureRecognizer was on the on of the parent view for UICollectionView .

UICollectionView was scrolling ok, but didSelectItemAt was never called.

Answer 11

In storyboard CollectionView Selectable is uncheck for me. once you checkmark Selectable then Collectionview didSelectItemsAt will call.

1. Go to your storyboard
2. Select your CollectionView
3. checkmark Selectable