Get rid of subview if collection view is empty

Question

I have a collection view when I display a message to the user if the collection view is empty. I also programmatically add a button to let the user add a photo if the collection view is empty. However, once the photo is added and the I reload the collection view, I found a way to get rid of the label, however, how can I get rid of the button's subview? since I can't access "self.collectionViews?.addSubview(button)" since it is in a guard let statement. Thanks in advance!

  guard let parseUSERS = parseJSON["users"] as? [AnyObject] else {


// if the collection view is empty, display a message
   let messageLabel = UILabel(frame: CGRect(x: 20.0, y: 10, width: self.collectionViews!.bounds.size.width - 40.0, height: (self.collectionViews?.bounds.size.height)!))
   messageLabel.text = "Collection view is empty!"
   messageLabel.font = messageLabel.font.withSize(20)
   messageLabel.font = UIFont.boldSystemFont(ofSize: messageLabel.font.pointSize)
   messageLabel.textColor = UIColor.white
   messageLabel.numberOfLines = 0
   messageLabel.textAlignment = NSTextAlignment.center
   messageLabel.sizeToFit()

   let button = UIButton(frame: CGRect(x: 80.0, y: 320, width: 215, height: 50))
   button.backgroundColor = UIColor.white
   button.setTitle("create",for: .normal)
   button.setTitleColor(colorCircleBlue, for: .normal)
   button.addTarget(self, action: #selector(self.action(sender:)), for: .touchUpInside)

   // round corners for login/register buttons
   button.layer.cornerRadius = button.bounds.width / 20

   self.collectionViews?.backgroundColor = UIColor.blue
   self.collectionViews?.backgroundView = messageLabel
   self.collectionViews?.addSubview(button)


    return
}


    self.collectionViews?.backgroundColor = UIColor.white
    self.collectionViews?.backgroundView = nil

Answer 1

I would recommend making a UIView that contains both your UILabel and the UIButton. Then setting the aforementioned UIView as the backgroundView of the UICollectionView. Ensure userInteraction is enabled on the backgroundView.

This will make sure that the both the UILabel & the UIButton are removed when you set the backgroundView to nil.

Something like this should do the trick (Be aware I have not tested this):

    //Container view
    let view = UIView.init(frame: self.collectionViews?.frame)
    //Label 
    let messageLabel = UILabel(frame: CGRect(x: 20.0, y: 10, width: self.collectionViews!.bounds.size.width - 40.0, height: (self.collectionViews?.bounds.size.height)!))
    messageLabel.text = "Collection view is empty!"
    messageLabel.font = messageLabel.font.withSize(20)
    messageLabel.font = UIFont.boldSystemFont(ofSize: messageLabel.font.pointSize)
    messageLabel.textColor = UIColor.white
    messageLabel.numberOfLines = 0
    messageLabel.textAlignment = NSTextAlignment.center
    messageLabel.sizeToFit()
    //Button
    let button = UIButton(frame: CGRect(x: 80.0, y: 320, width: 215, height: 50))
    button.backgroundColor = UIColor.white
    button.setTitle("create",for: .normal)
    button.setTitleColor(colorCircleBlue, for: .normal)
    button.addTarget(self, action: #selector(self.action(sender:)), for: .touchUpInside)
    // round corners for login/register buttons
    button.layer.cornerRadius = button.bounds.width / 20
    //Add elements to container view
    view.addSubview(messageLabel)
    view.addSubview(button)
    self.collectionViews?.backgroundView = view

Then in the future when you want to remove both elements you can just set the backgroundView to nil.