Var in extension class show error “Extensions must not contain stored properties”

Question

Since I have many vars and I would like put in new file. When I move var to new file in extension, I got error "Extensions must not contain stored properties". How can I solve it? What is best way to "Clean up" var? Here my code:

Class:

class ReminderMain: UIViewController {
   override func viewDidLoad() {
      //Do something
   }
}

Extension:

extension ReminderMain {
   var greeting = UILabel()
}

Answer 1

What you actually need is to follow an architecture for your project like MVC , MVP or MVVM these are the popular ones (there are many more). These architecture enable you to clean up your code and maintain a structure for your project.

Now for you scenario that you have explained above, you seem to have many stored properties like var greeting = UILabel() you might wanna move them into a view class and use only one view to set the view of the controller. Here's an example (in MVC):

class ViewController: UIViewController {
    let myView = View()
    override func loadView() {
        super.loadView()
        view = myView
        myView.model = Model(greetingText: "My greeting")
    }
}

class View: UIView {
    var model: Model? {
        didSet { greeting.text = model?.greetingText }
    }
    var greeting = UILabel()
    override init(frame: CGRect) {
        super.init(frame: frame)
        addSubview(greeting)
        // add all other sub-views and layout them here
    }
}
struct Model { var greetingText: String }

For more details about refactoring go through tutorials that explain this much better and in detail.