CODEWITHSUNDEEP
swift
moe safar
moe safar

Reputation: 150

Error in reading values of UITextfields

I'm having trouble reading the values from a textfield. Every time I type in this line let username = UsernameTextField.text I get an error saying "Cannot use instance member 'UsernameTextField' within property initializer; property initializers run before 'self' is available".

Here is the full code:

import UIKit

class SignInViewController: UIViewController,UITextFieldDelegate {
    @IBOutlet var UsernameTextField: UITextField!
    @IBOutlet var PasswordTextField: UITextField!
    @IBOutlet var LogInButton: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
        navigationController?.navigationBar.shadowImage = UIImage()
        navigationController?.navigationBar.isTranslucent = true
        navigationController?.view.backgroundColor = UIColor.clear
        // Remove Autocorrection Type
        UsernameTextField.autocorrectionType = .no
        PasswordTextField.autocorrectionType = .no
        PasswordTextField.textContentType = UITextContentType("")
        //Next button takes user to the next textfield
        UsernameTextField.delegate = self
        PasswordTextField.delegate = self
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        if textField == UsernameTextField{
            PasswordTextField.becomeFirstResponder()

        } else if textField == PasswordTextField {
            self.view.endEditing(true)
        }
        return true
    }

    let username = UsernameTextField.text
}

Upvotes: 0

Views: 68

Answers (5)

user9535754
user9535754

Reputation:

You have to move you constants and place them right under "return true"

Upvotes: 0

Oren
Oren

Reputation: 61

Any chance that you have a subclass of UITextField called UsernameTextField? If so, it might be referencing the class instead of the instance.

I would recommend keeping variables' names camelCased. Makes it easier to differentiate between variables and classes.

If this is the convention you use, you might also try using

let name = self.UsernameTextField.text

EDIT:

It seems that this line is outside the function scope. Should move it before the closing }.

Upvotes: 1

Yoni Reiss
Yoni Reiss

Reputation: 350

As the error suggests "UsernameTextField" is an instance member which means it does not get instantiated until the class is instantiated (as opposed to static members) which means that by the time your line is compiled which is before the class is instantiated, that member does not exist yet.

Upvotes: 0

Jake
Jake

Reputation: 2216

That is what you have, the call to set the text is NOT in a function.

func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    if textField == UsernameTextField{
        PasswordTextField.becomeFirstResponder()

    } else if textField == PasswordTextField {
        self.view.endEditing(true)
    }
    return true
}

let username = UsernameTextField.text // THIS IS NOT IN A FUNCTION

Move it here:

func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    if textField == UsernameTextField{
        PasswordTextField.becomeFirstResponder()
    } else if textField == PasswordTextField {
        self.view.endEditing(true)
    }
    let username = UsernameTextField.text // THIS IS NOW IN A FUNCTION    
    return true
}

Upvotes: 1

Matthias Grün
Matthias Grün

Reputation: 1496

The line

let username = UsernameTextField.text

is in the scope of your class definition, not inside the scope of a method. Therefore this constitutes a property initialization which is run upon construction of an instance of the class. You're trying to initialize the member variable username using ANOTHER member variable (UsernameTextField). This, of course, cannot work, since the object has to be fully initialized before any members can be read.

Did you mean to put the line inside the scope of the method textFieldShouldReturn?

Upvotes: 0

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