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iOS Delegates in Swift 2 Delegation in iOS Modifying Behavior With Delegates

count the length of a String - Swift Delegate

Hi, in the video, count is done like this:

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
        let length = count(textField.text) - range.length + count(string) // but this error occurred: "Cannot invoke 'count' with an argument list of type '(String?)'"
        if length > 0 {
            submitButton.enabled = true
        } else {
            submitButton.enabled = false
        return true

what I do?

2 Answers

Eduardo Pinheiro
Eduardo Pinheiro
4,649 Points

If you're using Xcode 7, you need to change 'count(textField.text)' to 'textField.text!.characters.count' and 'count(string)' to 'string.characters.count'.

gurminder thind
gurminder thind
Courses Plus Student 10,062 Points

Correct code for Xcode 8.1 is () func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { let length = (textField.text?.characters.count)! - range.length + string.characters.count if length > 0 { submitButton.isEnabled = true } else { submitButton.isEnabled = false } return true } ()

Please note that count(textField.text) has been changed to (textField.text?.characters.count)! in Xcode 8.1 and also 'submitButton.enabled' has been changed to 'submitButton.isEnabled'. Again it will be nice if put in teacher's notes.