How to change label text according to TextField content while edited

Question

I've just approached Swift and I'm trying to learn some very basic stuff.

I'm trying to achieve this:

I have a TextField and an Label, and I want the Label to be set to a specific emoji, according to the TextField text (which should a country name).

Example:

If the TextField contains the word "Italy", I want the Label to be set to "".

If the TextField contains the word "Mexico", the Label should be set to "".

This should happen while the TextField is being edited, not using any button to confirm the text in it.

This is my (not working, obviously) code.

@IBOutlet weak var emojiLabel: UILabel!
@IBOutlet weak var myTestField: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    changeLabel()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func changeLabel() {

    emojiLabel.text = ""
    var countryName = myTestField.text

    if (countryName == "Italia") {
        emojiLabel.text = ""
        print (emojiLabel)
    }

}

Have a look here: https://stackoverflow.com/questions/28394933/how-do-i-check-when-a-uitextfield-changes — Teetz, Aug 09 '18 at 20:13

score 4 · Accepted Answer · answered Aug 09 '18 at 20:28

The first thing you want to do is set up a dictionary with all of the pairs you want, for example:

    //Put this line outside of viewDidLoad
    var dictionary: [String: String] = [:]

    //Put these lines inside of viewDidLoad
    dictionary["Italy"] = ""
    dictionary["Mexico"] = ""
    //...Add more pairs to the dictionary

Now that you have defined all of your pairs, the next thing you want to do is setup the delegate of your text field. Doing this allows you to run some block of code whenever text is entered into your textfield. First, in your view controllers class definition, you want to conform to the UITextFieldDelegate:

class ViewController: UIViewController, UITextFieldDelegate {
    //...rest of the code in the view controller
}

Then, in your viewDidLoad, you want to set the delegate of your text field to self (a.k.a. to this view controller, which we have just conformed to the UITextFieldDelegate):

override func viewDidLoad() {
    super.viewDidLoad()
    //...rest of code in viewDidLoad
    myTestField.delegate = self
}

Now, with all of that out of the way, we want to call this function, just start typing textfield and it will autocomplete because we have already conformed to the UITextFieldDelegate:

func textFieldDidEndEditing(_ textField: UITextField) {
    //...This function is called EVERY time editing is finished in myTestField
}

Ok, so inside of the textFieldDidEndEditing function, all we need to do is check what was entered in myTestField and see if it matches any of the keys in the dictionary we created in the first step...if it does, then we are finally going to update our label:

func updateLabel(textField: UITextField) {
    //we are using guard here because we are dealing with optional values, 
    //meaning that textField.text doesn't necessarily have a value, and  
    //dictionary[text] may not actually have a value either.
    guard let text = textField.text,
        let labelText = dictionary[text] else {return}
    //Now we are going to actually update our label
    emojiLabel.text = labelText
}

Ok, looking good, last thing to do is just call our updateLabel function inside of the textFieldDidEndEditing function:

func textFieldDidEndEditing(_ textField: UITextField) {
    //...This function is called EVERY time editing is finished in myTestField
    updateLabel(textField: textField)
}

That's it!

I see you found a solution but you really should at least be using a dictionary do store your pairs instead of checking with conditionals — Greg, Aug 09 '18 at 20:37
Thank you so much @Greg ! This solution is definitely more elegant and efficient than mine. As a new Swift programmer, I can only thank you for the things you shown me with your code! Again, thank you so much! — Mehdi Brando Mahdloo, Aug 09 '18 at 23:09
No problem, as an added challenge, you should try to reorganize this code by putting all of the UITextFieldDelegate stuff into a separate swift file that extends the view controller, this will make things much cleaner and is a good habit to get into. Let me know if you need to see the code for that. — Greg, Aug 10 '18 at 16:32
Great suggestion. I’ll give it a shot myself and I’ll let you know if I need help. So happy there’s people like you Greg. Thank you so much. — Mehdi Brando Mahdloo, Aug 10 '18 at 16:35

Mehdi Brando Mahdloo · Answer 2 · 2018-08-10T07:39:00.543

I made it thanks to Teetz comment. This is my working code if someone else needs it:

EDIT 1: I strongly recommend to use the Greg solution, marked as answer.

@IBOutlet weak var emojiLabel: UILabel!
@IBOutlet weak var myTestField: UITextField!

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    myTestField.addTarget(self, action: #selector(ViewController.textFieldDidChange(_:)), for: UIControlEvents.editingChanged)
    textFieldDidChange(myTestField)

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@objc func textFieldDidChange(_ textField: UITextField) {

    emojiLabel.text = ""
    var countryName = myTestField.text

    if (countryName == "Italia") {
        emojiLabel.text = ""
    }

}

How to change label text according to TextField content while edited

2 Answers2