How to add UICollectionView inside UIAlertViewController?

Question

There are similar question on stackoverflow How to add UITableView in a UIAlertView in swift and How to add a UITableView inside the UIAlertView in iPhone? but I am adding UICollectionView inside UIAlertViewController and I am getting crash

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UICollectionView view]: unrecognized selector sent to instance 0x103808200'

I am using below Code

class NewProjectViewController: UIViewController {
    var iconCollectionView:UICollectionView!
    @IBAction func projectIconAction(_ sender: UIButton) {
        selectIcon()
    }
}

extension NewProjectViewController:UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout
{
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return Constant.iconArray.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell:UICollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath as IndexPath)

        cell.backgroundColor = UIColor.blue
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize
    {
        return CGSize(width: 50, height: 50)
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets
    {
        return UIEdgeInsets(top: 5, left: 5, bottom: 5, right: 5)
    }

    func selectIcon() {

        let flowLayout = UICollectionViewFlowLayout()
        iconCollectionView = UICollectionView(frame: self.view.bounds, collectionViewLayout: flowLayout)
        iconCollectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
        iconCollectionView.delegate = self
        iconCollectionView.dataSource = self

        let alertController:UIAlertController = UIAlertController(title: "ICON", message: "", preferredStyle: UIAlertControllerStyle.alert)
        alertController.addAction(UIAlertAction(title: "Select", style: UIAlertActionStyle.default, handler: { (action) in
            print("Icon Selected")
        }))
        alertController.setValue(iconCollectionView, forKey: "contentViewController")
        alertController.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.destructive, handler: nil))
        self.present(alertController, animated: true, completion: nil)
    }

}

Please let me know what I am doing wrong here

Edit 1: If I am using bellow code to add UICollectionViewController as subview to UIAlertController then I got out as in screenshot

func selectIcon() {

        let flowLayout = UICollectionViewFlowLayout()
        iconCollectionView = UICollectionView(frame: CGRect(x: 0, y: 80, width: 300, height: 300), collectionViewLayout: flowLayout)
        iconCollectionView.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
        iconCollectionView.delegate = self
        iconCollectionView.dataSource = self

        let alertController:UIAlertController = UIAlertController(title: "ICON", message: "", preferredStyle: UIAlertControllerStyle.alert)
        alertController.addAction(UIAlertAction(title: "Select", style: UIAlertActionStyle.default, handler: { (action) in
            print("Icon Selected")
        }))
//        alertController.setValue(iconCollectionView, forKey: "contentViewController")
        alertController.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.destructive, handler: nil))
        alertController.view.addSubview(iconCollectionView)
        self.present(alertController, animated: true, completion: nil)
    }

Answer 1

Unfortunately such a thing is not possible with the Apple UIAlertController. As the answers to the question you linked suggest, you need to create a custom view to do this.

You can do this yourself, (refer to the other answer), or alternatively, many libraries exist that you can use.

I have personally used this one before and had great success with it.

Good luck!