如何在文本字段和标签中同时更改文本

Question

Anybody have idea how to write message at the textField and label at the same time? When I write message at the textField, I would like to see that text at the label, char by char, simultaneously....

Is there any UItextField delegate for that?

Answer 1

Try adding a listener to editingChanged of the textfeild

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

and

@objc func textFieldDidChange(_ textField: UITextField) {

 yourLabel.text = textField.text

}

Answer 2

We can bring the approach SH_Kahn has shown a bit further:

import UIKit


extension UILabel {
    @objc
    func input(textField: UITextField) {
        self.text = textField.text
    }
}

We add a method with a signature compatible with the add target mechanism. This method just will get textField's text and set it to the label's text.

class ViewController: UIViewController {

    @IBOutlet weak var outputLabel: UILabel!
    @IBOutlet weak var inputField: UITextField!
    override func viewDidLoad() {
        super.viewDidLoad()
        self.inputField.addTarget(outputLabel, action: #selector(UILabel.input(textField:)), for: .editingChanged)
    }


}

---

But if we need it more often, we might would like to make it even easier to use:

extension UILabel {
    @objc
    func input(textField: UITextField) {
        self.text = textField.text
    }

    func connect(with textField:UITextField){
        textField.addTarget(self, action: #selector(UILabel.input(textField:)), for: .editingChanged)
    }
}


class ViewController: UIViewController {

    @IBOutlet weak var outputLabel: UILabel!
    @IBOutlet weak var inputField: UITextField!
    override func viewDidLoad() {
        super.viewDidLoad()
        outputLabel.connect(with: inputField)
    }
}