Format number in android EditText after editing

NumberTextWatcher.kt

package com.toastme.widget

import android.text.Editable
import android.text.TextWatcher
import android.widget.EditText
import java.math.BigDecimal
import java.text.DecimalFormat

class NumberTextWatcher(private val editText: EditText) : TextWatcher {

    private val f = DecimalFormat("#$GROUP_SYMBOL###$DECI_SYMBOL##").apply {
        isDecimalSeparatorAlwaysShown = true
    }
    private val fNoDecimal = DecimalFormat("#$GROUP_SYMBOL###")
    private var hasFractionalPart = false

    override fun afterTextChanged(s: Editable) {
        editText.removeTextChangedListener(this)
        try {
            val initLen: Int = editText.text.length
            val cursorPos = editText.selectionStart
            val number = BigDecimal(s.replace(SEPARATOR_REGEX, ""))
            editText.setText(if (hasFractionalPart) f.format(number) else fNoDecimal.format(number))
            val endLen: Int = editText.text.length

            val sel = cursorPos + (endLen - initLen)
            if (sel > 0 && sel <= editText.text.length) {
                editText.setSelection(sel)
            } else {
                editText.setSelection(editText.text.length - 1)
            }
        } catch (e: Exception) {
            // ingore
        }
        editText.addTextChangedListener(this)
    }

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

    override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {
        val value = s.toString()
        hasFractionalPart = value.contains(DECI_SYMBOL)
            && !value.endsWith("${DECI_SYMBOL}00") //workaround to fix value like 1234.
    }

    companion object {
        const val GROUP_SYMBOL = ","
        const val DECI_SYMBOL = "."
        val SEPARATOR_REGEX = GROUP_SYMBOL.toRegex()
    }

}