How do you use Interface builder with Swift?

Question

When hooking Swift code up to a Storyboard, how do you add the IBAction and IBOutlet tags?

Parthenia

same way, ctrl+drag inside class block, then you choose if it's outlet or action – Annisannissa

@CalinChitu: Can you elaborate? I usually wire things up in the other direction - from IB to code. – Parthenia

yes, from IB to code, same as before. Just the interface it's not there anymore so you drag inside class to your code. And you have to pick if it's an outlet or action – Annisannissa

Answer 1

Add IBAction and IBOutlet attributes to variables and functions so they can be visible in Interface builder.

class ViewController: UIViewController {

    @IBOutlet var label: UILabel?

    @IBAction func doTap(x:UIButton) {
        println("Tapped: \(x)")
    }
}

Parthenia

You can also use @IBDesignable and @IBInspectable if you're developing your own controls. :) – Castorina

True. The Swift book also mentions these two new attributes, but I guess we have to wait for the NDA to be lifted before we can say more about them. – Parthenia

Actually we can publically discuss this: oleb.net/blog/2014/06/apple-lifted-beta-nda – Captor

I tried something like this and can't make it work. I see the outlet circle in the gutter of the ViewController.swift, but can't drag from it to the button or control-drag from the view to swift code... wonder if i'm doing something obviously wrong or it's a bug of some sort – Tiffie

The way I do it (and I'm sure there has to be a better way) is: 1) select the object in IB, 2) in the far-right pane select "connection inspector", 3) under "New Referencing Outlet" click the circle and drag it all the way to the view controller that has the @IBOutlet in the left-pane of IB. – Parthenia

I was doing it right, it's a bug in Xcode. I was trying to do it in an existing project and when i open the project, it was giving me a "something is wrong, no further information". When i create a completely new project it works well – Tiffie

Shouldn't it @IBOutlet weak var label: UILabel! ? – Dropforge

Answer 2

Below code shows IBOutlet and IBAction format in Swift :

class MyViewController: UIViewController {

  @IBOutlet weak var btnSomeButton: UIButton?
  @IBOutlet weak var lblLabelItem: UILabel?

  @IBAction func btnSomeButtonClicked(sender: UIButton) {
    ...
  }
}

You can bind them same way as done in Objective-C.

Conjugated

Answer 3

Just use old ctrl + drag technique which was popular in Xcode5 and everything works fine.

Bonina

If the control-drag technique isn't working, make sure you have the class in IB set to match the name of your custom swift view controller class. – Cerise

Answer 4

I would agree more with Jayprakash than the upvoted first answer. The only thing I would correct is the marking of the IBOutlets as implicitly unwrapped with the ! The first answer used to be correct, but several changes were made in Swift and how it interacts with IB in the latest release. In Swift, IBOutlets no longer have any implicit behavior or magic--they are simply annotations for IB. As of the date of this response, the following code is correct:

// How to specify an the equivalent of IBOutletCollection in Swift
@IBOutlet var fields: [UITextField]!
// How to specify a standard IBOutlet
@IBOutlet weak var button: UIButton!
// How to specify an IBAction
@IBAction func buttonWasPressed(sender: UIButton) { ... } 

Liggitt

Answer 5

While creating a project, you should have selected the storyboard, so that you can add your IBOutlet's directly in the story board.

The Below code gives you a idea of how to add IBOutlet to the UILabel

class ViewController: UIViewController {

    @IBOutlet var label : UILabel

}

Lovelace

IBOutlet has non-optional type UIButton – Outworn