FullCode.kt

package com.sharyfire.countryphonedetector

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.text.Editable
import android.text.TextWatcher
import android.util.Log
import io.michaelrocks.libphonenumber.android.NumberParseException
import io.michaelrocks.libphonenumber.android.PhoneNumberUtil
import io.michaelrocks.libphonenumber.android.Phonenumber.PhoneNumber
import kotlinx.android.synthetic.main.activity_main.*

private const val TAG = "MainActivity"

class MainActivity : AppCompatActivity() {
    private lateinit var phoneNumberUtil: PhoneNumberUtil

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        phoneNumberUtil = PhoneNumberUtil.createInstance(this)

        phoneNumberEditText.addTextChangedListener(object : TextWatcher {
            override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
            }

            override fun onTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
            }

            override fun afterTextChanged(editable: Editable?) {
                val number = editable.toString()
                val countryIsoCode = getCountryIsoCode(number)
                countryTextView.text = countryIsoCode ?: "Can't detect a country"
            }
        })
    }

    private fun getCountryIsoCode(number: String): String? {
        val validatedNumber = if (number.startsWith("+")) number else "+$number"

        val phoneNumber = try {
            phoneNumberUtil.parse(validatedNumber, null)
        } catch (e: NumberParseException) {
            Log.e(TAG, "error during parsing a number")
            null
        }
        if(phoneNumber == null) return null

        return phoneNumberUtil.getRegionCodeForCountryCode(phoneNumber.countryCode)
    }
}