How do I check when a UITextField changes?

Question

I am trying to check when a text field changes, equivalent too the function used for textView - textViewDidChange so far I have done this:

  fu         


        

Answer 1

The way I've handled it so far: in UITextFieldDelegate

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
{
    // text hasn't changed yet, you have to compute the text AFTER the edit yourself
    let updatedString = (textField.text as NSString?)?.stringByReplacingCharactersInRange(range, withString: string)

    // do whatever you need with this updated string (your code)


    // always return true so that changes propagate
    return true
}

Swift4 version

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let updatedString = (textField.text as NSString?)?.replacingCharacters(in: range, with: string)
    return true
}

Answer 2

Swift 4

textField.addTarget(self, action: #selector(textIsChanging), for: UIControlEvents.editingChanged)

@objc func textIsChanging(_ textField:UITextField) {

 print ("TextField is changing")

}

If you want to make a change once the user has typed in completely (It will be called once user dismiss keyboard or press enter).

textField.addTarget(self, action: #selector(textDidChange), for: UIControlEvents.editingDidEnd)

 @objc func textDidChange(_ textField:UITextField) {

       print ("TextField did changed") 
 }

Answer 3

Maybe use RxSwift ?

need

pod 'RxSwift',    '~> 3.0'
pod 'RxCocoa',    '~> 3.0'

add imports obviously

import RxSwift
import RxCocoa

So u have a textfield : UITextField

let observable: Observable<String?> = textField.rx.text.asObservable()
observable.subscribe(
            onNext: {(string: String?) in
                print(string!)
        })

U have other 3 methods..

1. onError
2. onCompleted
3. onDisposed
4. onNext

Answer 4

Swift 3

 textField.addTarget(self, action: #selector(ViewController.textFieldDidChange(sender:)), for: UIControlEvents.editingChanged)

Answer 5

Swift 4.2

write this in viewDidLoad

// to detect if TextField changed
TextField.addTarget(self, action: #selector(textFieldDidChange(_:)),
                                   for: UIControl.Event.editingChanged)

write this outside viewDidLoad

@objc func textFieldDidChange(_ textField: UITextField) {
    // do something
}

You could change the event by UIControl.Event.editingDidBegin or what ever you want to detect.

Answer 6

SWIFT

Swift 4.2

textfield.addTarget(self, action: #selector(ViewController.textFieldDidChange(_:)), for: .editingChanged)

and

@objc func textFieldDidChange(_ textField: UITextField) {

}

SWIFT 3 & swift 4.1

textField.addTarget(self, action: #selector(ViewController.textFieldDidChange(_:)), for: .editingChanged)

and

func textFieldDidChange(_ textField: UITextField) {

}

SWIFT 2.2

textField.addTarget(self, action: #selector(ViewController.textFieldDidChange(_:)), forControlEvents: UIControlEvents.EditingChanged)

and

func textFieldDidChange(textField: UITextField) {
    //your code
}

OBJECTIVE-C

[textField addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];

and textFieldDidChange method is

-(void)textFieldDidChange :(UITextField *) textField{
    //your code
}