Where to set UiTextField delegate method in custom UiView

Question

Error occurs when I set UITextField delegate.

My code is:

import UIKit

class UserAlertVC: UIView , UITextFieldDelegate {
/*
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
    // Drawing code
}
*/

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

}

required init(coder aDecoder: NSCoder) {

    super.init(coder: aDecoder)!
    self.addBehavior()

}


func addBehavior (){
    print("Add all the behavior here")
    userNameTxtField.delegate = self
    passwordTxtField.delegate = self

}


func textFieldShouldReturn(textField: UITextField) -> Bool {

    return true
}

func textFieldDidBeginEditing(textField: UITextField) {

}


@available(tvOS 10.0, *)
func textFieldDidEndEditing(textField: UITextField, reason: UITextFieldDidEndEditingReason) {

}

@IBAction func actionOnCancel(sender: UIButton) {
    self .removeFromSuperview()


}


@IBAction func actionOnProceed(sender: UIButton) {
    self .removeFromSuperview()
UserAlertVC.showAlertForUser()


}

@IBOutlet var userNameTxtField: UITextField!

@IBOutlet var passwordTxtField: UITextField!

static func showAlertForUser() {

    let alert       = NSBundle.mainBundle().loadNibNamed("KeyboardViewController", owner: self, options: nil)!.last as! UIView
    let windows     = UIApplication.sharedApplication().windows
    let lastWindow  = windows.last
    alert.frame     = UIScreen.mainScreen().bounds
    lastWindow?.addSubview(alert)


}
}

Error message is:

fatal error: unexpectedly found nil while unwrapping an Optional value

I have used Custom Alert View using XIB.pls suggest any solution.

Answer 1

Firstly take a look at life cycle of the view. Depending on this it is possible to highlight that method awakeFromNib is quite suitable because:

The nib-loading infrastructure sends an awakeFromNib message to each object recreated from a nib archive, but only after all the objects in the archive have been loaded and initialized. When an object receives an awakeFromNib message, it is guaranteed to have all its outlet and action connections already established.

Answer 2

Make sure to put an @IBOutlet for the .Xib content view, also you need to add the Nib code. Last, make sure in your ViewController you set your UIView Outlet to be UserAlertVC and you add the awakeFromNib method. Please find attached the code. Let me know if you need further help.

Here is the code related to the .xib file.

import UIKit

class UserAlertVC: UIView, UITextFieldDelegate {

//MARK: - Outlets

@IBOutlet var contentView: UIView!
@IBOutlet var userNameTxtField: UITextField!
@IBOutlet var passwordTxtField: UITextField!

//MARK: - Loads

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

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

//MARK: - Functions

func commonInit() {
    Bundle.main.loadNibNamed("UserAlertVC", owner: self, options: nil)
    userNameTxtField.delegate = self
    passwordTxtField.delegate = self

    contentView.translatesAutoresizingMaskIntoConstraints = false

    addSubview(contentView)

    // add constraints programmatically
}

// add the rest of your code

}

Here is the code related to the ViewController.

class ViewController: UIViewController {

//MARK: - Outlets

@IBOutlet weak var userAlertVC: UserAlertVC!

//MARK: - Loads

override func viewDidLoad() {
    super.viewDidLoad()
}

override func awakeFromNib() {
    super.awakeFromNib()
}

}