IP address textbox in Android?

Based on NathanOliver's and enneract's code I wrote, in kotlin, a variation that insertes a dot when one is deleted.

class IpAddressEditText : AppCompatEditText {

    constructor(context: Context) : super(context) {
        init()
    }

    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        init()
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int) : super(context, attrs, defStyleAttr) {
        init()
    }

    private fun init() {
        // phone input type to show the numeric keyboard in all kinds of devices
        inputType = InputType.TYPE_CLASS_PHONE

        // restrict the input of the characters specified in string bellow
        keyListener = DigitsKeyListener.getInstance("0123456789.")

        // InputFilter decides what can be typed
        filters = arrayOf(InputFilter { source, start, end, dest, dstart, dend ->
            if (end > start) {
                val inputString = dest.toString()
                val substring = inputString.substring(0, dstart) + source.subSequence(start, end) + inputString.substring(dend)

                if (!substring.matches("^\\d{1,3}(\\.(\\d{1,3}(\\.(\\d{1,3}(\\.(\\d{1,3})?)?)?)?)?)?".toRegex())) {
                    // do not allow the input of:
                    //  segments with more than 3 characters and less than 1;
                    //  segments != 4;
                    return@InputFilter ""

                } else {
                    val splits = substring.split("\\.".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
                    for (i in splits.indices) {
                        // don't allow a segment with a value more than 255
                        if (Integer.valueOf(splits[i]) > 255) {
                            return@InputFilter ""
                        }
                    }
                }
            }
            null
        })

        // TextWatcher notifies what was typed
        addTextChangedListener(object : TextWatcher {
            var isDeleting = false
            var lastCount = 0

            override fun afterTextChanged(editable: Editable) {
                if (!isDeleting) {
                    val inputString = editable.toString()
                    val segmentList = inputString.split("\\.".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
                    val lastSegment = segmentList[segmentList.size - 1]

                    // each segment of the ip can have max size of 3 characters and a max value of 255
                    if (lastSegment.length == 3 || lastSegment.length == 2 && Integer.parseInt(lastSegment) > 25) {

                        // add a dot automatically if the conditions met
                        editable.append('.')
                        return
                    }
                } else {
                    // add a dot in the same position where it was deleted
                    editable.insert(selectionStart, ".")
                }
            }

            override fun onTextChanged(s: CharSequence, start: Int, before: Int, count: Int) {
                isDeleting = lastCount >= count
            }

            override fun beforeTextChanged(s: CharSequence, start: Int, count: Int, after: Int) {
                // do nothing
            }
        })
    }
}

Here is the code that limits a user to only enter numbers and dots by displaying a soft keyboard with only numbers and a dot (but allows you to enter multiple dots).

 etIpAddress.setInputType(InputType.TYPE_CLASS_NUMBER);
 etIpAddress.setInputType(InputType.TYPE_NUMBER_FLAG_DECIMAL);
 etIpAddress.setKeyListener(DigitsKeyListener.getInstance(false,false));
 etIpAddress.setKeyListener(DigitsKeyListener.getInstance("0123456789."));