android kotlin - Secondary progress bar example

MainActivity.kt

package com.cfsuman.kotlintutorials

import android.app.Activity
import android.os.Bundle
import android.os.Handler
import android.os.Looper
import android.view.View
import android.widget.Button
import android.widget.ProgressBar
import android.widget.TextView
import androidx.constraintlayout.widget.ConstraintLayout
import androidx.transition.TransitionManager


class MainActivity : Activity() {
    var progressStatus = 0
    var secondaryProgressStatus = 0
    var handler = Handler(Looper.getMainLooper())

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

        // Get the widgets reference from XML layout
        val rootLayout = findViewById<ConstraintLayout>(R.id.rootLayout)
        val button = findViewById<Button>(R.id.button)
        val textView = findViewById<TextView>(R.id.textView)
        val tvSecondary = findViewById<TextView>(R.id.tvSecondary)
        val progressBar = findViewById<ProgressBar>(R.id.progressBar)


        // button click listener
        button.setOnClickListener {
            button.isEnabled = false
            TransitionManager.beginDelayedTransition(rootLayout)
            progressBar.visibility = View.VISIBLE

            // set up progress bar on initial stage
            progressBar.progress = 0
            progressStatus = 0

            Thread {
                while (progressStatus < 100) {

                    while (secondaryProgressStatus < 100) {
                        secondaryProgressStatus += 1
                        Thread.sleep(5)

                        handler.post {
                            progressBar.secondaryProgress =
                                secondaryProgressStatus

                            if (secondaryProgressStatus == 100) {
                                tvSecondary.text = "Secondary task finished."
                                secondaryProgressStatus = 0

                                progressStatus += 1
                                progressBar.progress = progressStatus
                                textView.text = "Task finished" +
                                        " $progressStatus of 100"

                                if (progressStatus == 100) {
                                    button.isEnabled = true
                                }
                            } else {
                                tvSecondary.text = "Secondary task " +
                                        "$secondaryProgressStatus of 100"
                            }
                        }
                    }
                }
            }.start()
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/rootLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="24dp"
    android:background="#DCDCDC">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:padding="12dp"
        android:fontFamily="sans-serif"
        android:textSize="20sp"
        android:textStyle="bold"
        tools:text="TextView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="12dp"
        android:visibility="invisible"
        android:secondaryProgressTint="#0018A8"
        android:secondaryProgressTintMode="src_in"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView" />

    <TextView
        android:id="@+id/tvSecondary"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:fontFamily="sans-serif"
        android:padding="12dp"
        android:textSize="18sp"
        android:textStyle="italic"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.491"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/progressBar"
        tools:text="Secondary Task" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="Start Task"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvSecondary" />

</androidx.constraintlayout.widget.ConstraintLayout>