How do I use performSegue to get to another UIViewController?

Question

I tried to connect my ViewController to a CollectionViewController with a segue between the two. I control+clicked from the ViewController to the CollectionView Controller and selected the 'show detail' segue, and then made a button with this code:

class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    print("ViewController loaded")
}

@IBAction func EditCharacterSetPressed(_ sender: UIButton) {
    self.performSegue(withIdentifier: "CollectionViewSegue", sender: self)
}

When I press the button in the simulator, it gives me this error message:

How do I fix this? Does it have something to do with these other warnings about my CollectionView?:

I have an Identifier, so that's not the problem:

Answer 1

EDIT: Problem was, he had non-existent IBAction connected to his button.

It seems like your segue does not have an identifier in your storyboard. Based on your code, it should be

CollectionViewSegue

Regarding your collection view cells. If I recall correctly (did objective-c couple of years back) xcode is creating instances of new Cell and not re-using any of the existing, because you don't have prototype cells defined.

You can (and should) create a cell (either in storyboard, or purely in code), set an identifier to that cell and reuse it in your table view controllers (or in this case in your collection view).

I guess you are just starting with the development, so I would suggest to go through couple of tutorials (e.g. http://www.thomashanning.com/uitableview-tutorial-for-beginners/)