MainActivity.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.content.res.ColorStateList
import android.graphics.Color
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
import kotlin.random.Random
class MainActivity : Activity() {
var progressStatus = 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 progressBar = findViewById<ProgressBar>(R.id.progressBar)
val progressBar2 = findViewById<ProgressBar>(R.id.progressBar2)
val progressBar3 = findViewById<ProgressBar>(R.id.progressBar3)
// change the indeterminate progress color programmatically
progressBar3.indeterminateTintList =
ColorStateList.valueOf(Color.RED)
// button click listener
button.setOnClickListener {
button.isEnabled = false
TransitionManager.beginDelayedTransition(rootLayout)
progressBar.visibility = View.VISIBLE
progressBar2.visibility = View.VISIBLE
progressBar3.visibility = View.VISIBLE
// set up progress bar on initial stage
progressBar.progress = 0
progressStatus = 0
// generate random number of files to download
val filesToDownload= Random.nextInt(200,500)
// set up max value for progress bar
progressBar.max = filesToDownload
Thread(Runnable {
while (progressStatus < filesToDownload){
// update progress status
progressStatus +=1
// sleep the thread for 50 milliseconds
Thread.sleep(50)
// update the progress bar
handler.post {
// calculate the percentage
val percentage = ((progressStatus.toDouble()
/ filesToDownload) * 100).toInt()
// update the text view
textView.text = "Downloaded $progressStatus of " +
"$filesToDownload files ($percentage%)"
if (progressStatus == filesToDownload){
button.isEnabled = true
TransitionManager
.beginDelayedTransition(rootLayout)
progressBar.visibility = View.INVISIBLE
progressBar2.visibility = View.INVISIBLE
progressBar3.visibility = View.INVISIBLE
}
}
}
}).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"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="64dp"
android:layout_marginTop="12dp"
android:visibility="invisible"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView" />
<ProgressBar
android:id="@+id/progressBar2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="invisible"
android:indeterminateTint="#0018A8"
android:indeterminateTintMode="src_in"
android:layout_marginStart="16dp"
app:layout_constraintBottom_toBottomOf="@+id/progressBar"
app:layout_constraintStart_toEndOf="@+id/progressBar" />
<ProgressBar
android:id="@+id/progressBar3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="invisible"
android:layout_marginStart="16dp"
app:layout_constraintBottom_toBottomOf="@+id/progressBar2"
app:layout_constraintStart_toEndOf="@+id/progressBar2" />
<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/progressBar" />
</androidx.constraintlayout.widget.ConstraintLayout>