kotlin version of EditText custom PaswordTranformationMethod that will make last character visible, taken from this stack overflow https://stackoverflow.com/a/15569637/616280

PasswordTransformLastVisible.kt

//add your package here 

import android.text.method.PasswordTransformationMethod
import android.view.View

/**
 * make edittext masked except last character
 * source : https://stackoverflow.com/a/15569637/616280
 */
object PasswordTransformLastVisible : PasswordTransformationMethod() {

    override fun getTransformation(source: CharSequence?, view: View?): CharSequence {
        return PasswordCharSequence(source!!)
    }

    class PasswordCharSequence(private val source: CharSequence) : CharSequence {
        override val length = source.length

        override fun get(index: Int): Char {
            return if (index != source.lastIndex) '•' else source[index]
        }

        override fun subSequence(startIndex: Int, endIndex: Int): CharSequence {
            return source.subSequence(startIndex, endIndex)
        }
    }
}