How to validate EditText in android in real time while entering the value in the input field before button click, like we do with jquery in web

Question

I have to validate the EditText field in android in real time without clicking the button.

I have tried the validation with the requestFocus() method and setErrors() method but it gives the error after the button click. so is there any way?

Answer 1

Try using a TextWatcher.

There are Kotlin extension functions for this though, you can probably get away with something like this:

editText.doOnTextChanged { text, start, before, count ->  
    // Validate text
}

Answer 2

To Vaildate editText you can use before button click, you can use TextWatcher, It's Use to listen for changes in edittext. Please look into below example:

editText.addTextChangedListener(object : TextWatcher {
            override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
                // This method is called to notify you that characters within s are about to be replaced with new text with a length of after
                // For example, you might use it to disable a button until a certain number of characters are entered.
            }

            override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
                // This method is called to notify you that somewhere within s, the text has been changed.
                // For example, you might use it to dynamically update a preview as the user types.
            }

            override fun afterTextChanged(s: Editable?) {
                // This method is called to notify you that somewhere within s, the text has been changed.
                // It is called to notify you that somewhere within s, the text has been changed.
                // For example, you might use it to perform validation on user input.
                textView.text = "Entered Text: ${s.toString()}"
            }
        })