MainActivity.kt

package org.nixan.sandboxapp

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.widget.Button
import android.widget.EditText
import android.widget.Toast
import ru.nixan.regexpformatter.RegExpFormatter

class MainActivity : AppCompatActivity() {

    val regExpFormatter = RegExpFormatter("\\d{3}-\\d{3}")

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        (findViewById(R.id.testEdit) as EditText).addTextChangedListener(regExpFormatter)
        (findViewById(R.id.testEdit) as EditText).setRawInputType(regExpFormatter.inputType)
        (findViewById(R.id.triggerButton) as Button).setOnClickListener {
            if (regExpFormatter.check((findViewById(R.id.testEdit) as EditText).text.toString())) {
                Toast.makeText(this, "OK", Toast.LENGTH_LONG).show()
            } else {
                Toast.makeText(this, "Incorrect", Toast.LENGTH_LONG).show()
            }
        }
    }
}