Mask phone number

MaskPhoneNumber.kt

fun maskPhoneNumber(input: String): String {
    fun removeNonNumericalChar(input: String): String {
        val result = StringBuilder()
        for (char in input) {
            if (char.isDigit()) {
                result.append(char)
            }
        }
        return result.toString()
    }
    val digits = removeNonNumericalChar(input)
    val length = digits.length

    val maskedDigit = when (length) {
        10 -> digits.substring(0, 2) + "****" + digits.substring(6)
        11 -> digits.substring(0, 3) + "****" + digits.substring(7)
        12 -> digits.substring(0, 4) + "****" + digits.substring(8)
        else -> return input
    }
    return maskedDigit
}

RecyclerViewSupportRightToLeftScroll.kt

fun main() {
  binding.recyclerView.adapter = RecyclerViewAdapter
  binding.recyclerView.addOnScrollListener(EndlessRecyclerViewScroll())
}

class RecyclerView: Adapter {
}

class EndlessRecyclerViewScroll: RecyclerView.OnScrollListener() {
   
    val page = 1
   
    override fun onScrollStateChanged(recyclerView: RecyclerView) {
        recyclerView.layoutDirection // View.Layout_Direction.RTL
       
        if (!recyclerView.canScrollHorizontal(direction = -1)) { // can scroll left
            page ++
            onLoadMore(page)
        }
        if (!recyclerView.canScrollHorizontal(direction = 1)) { // can scroll right
            page ++
            onLoadMore(page)
        }
    }
   
    abstract fun onLoadMore(page: Int)
}

1. Write a function to mask the middle 4 digital of the Malaysia phone number, it should support different phone number type ,for example

+60 11-1549 1767 -> 6011****1767
+601115491767 -> 6011****1767
1115491767 -> 11****1767
+60 1115491767 -> 6011****1767

public func maskPhoneNumber(phoneNumber: String) -> String {
    var result = ""
    // add code to implement the mask phone number feature
    return result
}

2. RecyclerView support Right to Left scrolling, and pagination