CODEWITHSUNDEEP
swiftuibuttonswift-protocols
Brewski
Brewski

Reputation: 684

Delegate Method is not called in UIButton class

I have a UIbutton class - from which I would like to call an 'adjust constraints' method after the user makes changes on the setting screen. I have created some protocols and all seems in order but it is not calling the method from the subview UIButton after the user closes the Setting Screen.

I have tried some of the other solutions here - that hasn't worked and I think it might be because I am using a UIButton class and I can't reinstantiate it, or call the instantiation? Either way, it never calls the method from the delegate.

Is using protocols the right way to solve this problem and if so, what am I missing?

Basically I have 3 files; the MainVC which I set as my first delegate (it gets triggered from my SettingScreenVC when user is done making changes to Setting Screen):

class MainVC: UIViewController, SettingScreenDelegate {

    weak var numButtonDelegate: Buttons_Numeric?

    func settingSetButtonConstraints() {
        numButtonDelegate?.setupButtonConstraints()
    }
}

Then in my Setting Screen I call the MainVC after the user made some changes to their settings:

class MainVC: SettingScreenVC {

    weak var delegate: SettingScreenDelegate?

    func closeSettings() {
        delegate?.settingSetButtonConstraints()
    }

}

Then in my Buttons_Numeric class I declare the function and the UIButton class delegate:

protocol numButtonDelegate: class {
    func setupButtonConstraints()
}

class Buttons_Numeric: UIButton, numButtonDelegate {

    weak var numButtonDelegate: Buttons_Numeric?

    required init(coder aDecoder:NSCoder) { super.init(coder: aDecoder)!}

    override init(frame:CGRect) {super.init(frame: frame)
        self.numButtonDelegate = self
        setupButtonConstraints()
    }

    override func awakeFromNib() {
        self.numButtonDelegate = self
        setupButtonConstraints()
    }

    func setupButtonConstraints() {
        //SET UP CONSTRAINTS
    }
}

Upvotes: 0

Views: 387

Answers (2)

Mr Spring
Mr Spring

Reputation: 545

Ok so couple of things you need to understand about delegates:

  1. if you create a delegate, you need to conform to the delegate somewhere.
  2. the conforming class should be assigned to the instance of the delegate.

With that in mind lets try to fix the code:

first the settings screen:

protocol SettingScreenDelegate: class {
    func settingSetButtonConstraints()
}

class SettingScreenVC {
    weak var delegate: SettingScreenDelegate?

    func closeSettings() {
        delegate?.settingSetButtonConstraints()
    }
}

So far so good now the mainScreen should conform to the SettingScreenDelegate and be assigned to its delegate:

class MainVC: UIViewController, SettingScreenDelegate {
    
    weak var button: Buttons_Numeric!

    func openSettingsScreen() {
        let settingsScreen = ... // the setting screen instanciation
        settingsScreen.delegate = self // the MainVC
    }

    func settingSetButtonConstraints() {
        self.button.setupButtonConstraints()
    }
}

Now for the last step, the MainVC should have an instance of the button, then the only thing we need to do is call the function 'setupButtonConstraints' from the MainVC which means we do not need the delegate at the button.

class Buttons_Numeric: UIButton {

    required init(coder aDecoder:NSCoder) { super.init(coder: aDecoder)!}

    override init(frame:CGRect) {super.init(frame: frame)
        setupButtonConstraints()
    }

    override func awakeFromNib() {
        setupButtonConstraints()
    }

    func setupButtonConstraints() {
        //SET UP CONSTRAINTS
    }
}

Upvotes: 4

Jake
Jake

Reputation: 2216

You need to assign a value to the delegate variable. I would do it like this if the answer is always self

class Example: SomeDelegate {
    lazy var someDelegate: SomeDelegate? = self
}

Otherwise you'll want to do it in the class' initializer or ViewDidLoad.

Upvotes: 0

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