Example edit text with IBAN mask XXXX XXXX XXXX XXXX XXXX XXXX

editText_IBAN_mask.kt

package com.example.test

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.text.Editable
import android.text.TextWatcher
import com.example.test.databinding.ActivityMainBinding

class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        setUI()
    }

    private fun setUI() {

        binding.editTextTest.addTextChangedListener(object : TextWatcher {

            var _ignore = false
            var _deletion = false

            override fun afterTextChanged(s: Editable) {

                if (_ignore)
                    return

                _ignore = true

                if (!_deletion) {
                    binding.editTextTest.setText(getFormattedIBAN(s.toString()))
                    binding.editTextTest.setSelection(binding.editTextTest.text.toString().length)
                }

                _ignore = false

            }

            override fun beforeTextChanged(
                s: CharSequence, start: Int,
                count: Int, after: Int
            ) {
                _deletion = after < count
            }

            override fun onTextChanged(
                s: CharSequence, start: Int,
                before: Int, count: Int
            ) {
            }
        })

    }

    private fun getFormattedIBAN(text: String): String {

        val ibanMaxLength = 29

        if (text.length > ibanMaxLength) {
            return text.substring(0, ibanMaxLength - 1)
        }

        // Delete space in bad position.
        var result = ""
        text.forEachIndexed { index, c ->
            if (c.toString() == " " && (index + 1) % 5 != 0) {
            } else {
                result += c.toString()
            }
        }
        if (result != text) {
            return result.uppercase().trim()
        }


        // Add space after fourth digit
        if (text.replace(" ", "").length % 4 == 0) {
            return "$text ".uppercase()
        }

        return text.uppercase()
    }

}