Pass Array from View Controller To View Controller Returns Empty Array

Question

This type of question has been asked and answered, but my specific situation returns an empty array. I first create an array in View Controller 1 (VC1). VC1 includes a collection view. I try to add a UIView to the array in cellForItem func.

/// A subclass of `UIViewController` with a `MessagesCollectionView`  object
/// that is used to display conversation interfaces.

open class MessagesViewController: UIViewController,
UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {


public var cellViewArray = NSMutableArray() 

open func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath:    IndexPath) -> UICollectionViewCell {

let cell = messagesCollectionView.dequeueReusableCell(TextMessageCell.self, for: indexPath)
        cell.configure(with: message, at: indexPath, and: messagesCollectionView)

        let cellView = cell.contentView
        //print("cellView = \(cellView)")
        messageViewArray.insert(cellView, at: indexPath.row)
        //print("messageViewArray = \(String(describing: messageViewArray))")

return cell
}

I confirmed in debug that when the collection view runs, it does save the cellView to messageViewArray and neither are nil.

messageViewArray = (
"<UIView: 0x142913720; frame = (0 0; 359 140); autoresize = W+H; gestureRecognizers =  <NSArray: 0x142913d30>; layer = <CALayer: 0x1429138a0>>",
"<UIView: 0x14291bbc0; frame = (0 0; 359 256); autoresize = W+H; gestureRecognizers = <NSArray: 0x14291c1d0>; layer = <CALayer: 0x14291bd40>>",
"<UIView: 0x142929520; frame = (0 0; 359 256); autoresize = W+H; gestureRecognizers = <NSArray: 0x142929b30>; layer = <CALayer: 0x1429296a0>>",
"<UIView: 0x14298e610; frame = (0 0; 359 140); autoresize = W+H; gestureRecognizers = <NSArray: 0x14298ec20>; layer = <CALayer: 0x14298e790>>",
"<UIView: 0x142929520; frame = (0 0; 359 256); autoresize = W+H; gestureRecognizers = 
)

In View Controller 2 (VC2), I try to access messageViewArray from VC1 and do something with the UIView objects.

let messagesViewController  =  MessagesViewController()
print("messagesViewController.messageViewArray = \(messagesViewController.integerViewArray.description)")

This returns the below in debug showing empty array.

messagesViewController.messageViewArray = (
)

Why doesn't the array objects persist in VC2? What change can I make to reference messageViewArray in VC2. Thanks in advance for your time.

Answer 1

This works. You can access it directly. I'm not sure the exact reasoning, so someone else is welcome to explain.

In VC 2 - declare variable.

/// A subclass of `UIViewController` with a `MessagesCollectionView` object
/// that is used to display conversation interfaces.
open class MessagesViewController: UIViewController,
UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {

public static var arrayNameInVCTwo : NSMutableArray? = nil

In VC 1 - reference variable from VC 2

let arrayNameInVCOne = MessagesViewController.arrayNameInVCTwo