Swift correct declaration of object corresponding to protocol and having superclass

Question

I am Swift beginner and really stuck with this problem.

I have a prototype cell CurrencySwitchTableViewCell that is subclass of UITableViewCell.

class CurrencySwitchTableViewCell: UITableViewCell {
       @IBOutlet weak internal var currencySwitchDelegate: AnyObject!

This cell has a currencySwitchDelegate property that should be of CurrencySwitchDelegate protocol

protocol CurrencySwitchDelegate {
   func didSelectCurrency(currency:Currency)
}

How can I declare in CurrencySwitchTableViewCell that my currencySwitchDelegate is AnyObject corresponding to CurrencySwitchDelegate protocol?

What is Swift analog of Objective-C code like this?

NSObject<CurrencySwitchDelegate> or id<CurrencySwitchDelegate>

P.S.

I know I can just declare my property to be

@IBOutlet weak internal var currencySwitchDelegate: CurrencySwitchDelegate!

But XCode gives me error with @IBOutlet modifier (IBOutlets should be of AnyObject class)

Answer 1

An object have often a weak reference to the delegate and only objects can become weak references. You can inform the compiler that the delegate is an object by using : class

protocol CurrencySwitchDelegate: class {
   func didSelectCurrency(currency:Currency)
}

For the moment Xcode cannot IBOutlet protocol. The temporary solution is to create an other IBOutlet of type AnyObject and then cast it in your code.

@IBOutlet weak internal var outletDelegate: AnyObject?

private var delegate: CurrencySwitchDelegate? {
    return self.outletDelegate as! CurrencySwitchDelegate?
}