How to Display a Text in a Specific Time in Android using Handler?

package com.example.handler_time

import android.annotation.SuppressLint
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.Handler
import android.os.Looper
import android.widget.Button
import android.widget.TextView
import android.widget.Toast
import java.util.*

class MainActivity : AppCompatActivity() {
    lateinit var textView: TextView
    lateinit var button: Button

    private lateinit var handler: Handler

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Initialize views
        textView = findViewById(R.id.textview)
        button = findViewById(R.id.btn)

        // Set a click listener for the button
        button.setOnClickListener {
            // Initialize the handler on button click
            handler = Handler(Looper.getMainLooper())

            // Get the current time
            val currentTime = System.currentTimeMillis()

            val message = "Clicked the button wait 10 sec"
            Toast.makeText(this, message, Toast.LENGTH_LONG).show()

            // Display initial text and set a delayed action
            // to update text after 10 seconds
            handler.postDelayed({
                updateTextView("This is a testing application")

                // Set another delayed action to update text
                // after 10 seconds to show time has ended
                handler.postDelayed({updateTextView("Time has ended")}, 10 * 1000) 
                  // 10 seconds in milliseconds
                }, 0)
        }
    }

    // Function to update the TextView
    // with the provided text
    private fun updateTextView(text: String) {
        textView.text = text
    }
}