ProgressBar in Kotlin

Android ProgressBar is a user interface control that indicates the progress of an operation. For example, downloading a file, uploading a file on the internet we can see the progress bar to estimate the time remaining in operation. There are two modes of ProgressBar: 

• Determinate ProgressBar
• Indeterminate ProgressBar

Determinate ProgressBar

In common, we use the Determinate progress mode in ProgressBar because it shows the quantity of progress that has occurred like the (%) percentage of the file downloaded, how much data was uploaded or downloaded on the internet, etc. If we have to use determinate we set the style of the progress bar as below: 

XML

<ProgressBar
    android:id="@+id/pBar"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

Indeterminate ProgressBar

Here, we don’t get the idea of the progress of work means how much it has been completed or How long it will take to complete. 
We can use indeterminate progressBar like below by setting the indeterminate attribute as true. 

XML

<ProgressBar
    android:id="@+id/pBar"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:indeterminate="true"/>

Different Attributes of ProgressBar Widgets

XML Attributes	Description
android:id	Used to uniquely identify the control
android:min	Used to set minimum value
android:max	Used to set the maximum value
android:progress	Used to set the default progress integer value between 0 and max.
android:minHeight	Used to set the height of the progress bar.
android:minWidth	Used to set the width of the progress bar.
android:background	Used to set the background color for progress bar
android:indeterminate	Used to enable indeterminate progress mode.
android:padding	Used to set the padding for left, right, top, or bottom of the progress bar.

Add ProgressBar Widget in activity_main.xml file

XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!-- adding progress bar -->
    <ProgressBar
        android:id="@+id/progress_Bar"
        style="?android:attr/progressBarStyle"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="70dp"
        android:layout_marginTop="150dp"
        android:indeterminate = "true"
        android:max="100"
        android:minWidth="200dp"
        android:minHeight="50dp"
        android:visibility="invisible"
        android:layout_centerInParent="true"
        android:progress="0"
        android:layout_marginStart="70dp" />

    <!-- adding textview which will show the progress -->
    <TextView
        android:id="@+id/text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/progress_Bar"
        android:layout_centerHorizontal="true" />

     <!-- adding button to start the progress -->
    <Button
        android:id="@+id/show_button"
        android:layout_width="191dp"
        android:layout_height="wrap_content"
        android:layout_below="@+id/text_view"
        android:layout_marginLeft="70dp"
        android:layout_marginTop="20dp"
        android:text="Progress Bar"
        android:layout_centerHorizontal="true"
        android:layout_marginStart="70dp" />

</RelativeLayout>

Access the ProgressBar Widget in MainActivity.kt file

Kotlin

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.ProgressBar
import android.widget.TextView
import android.os.Handler

class MainActivity : AppCompatActivity() {

    private var progressBar: ProgressBar? = null
    private var i = 0
    private var txtView: TextView? = null
    private val handler = Handler()

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

        // finding progressbar by its id
        progressBar = findViewById<ProgressBar>(R.id.progress_Bar) as ProgressBar

        // finding textview by its id
        txtView = findViewById<TextView>(R.id.text_view)

        // finding button by its id
        val btn = findViewById<Button>(R.id.show_button)

        // handling click on button
        btn.setOnClickListener {
            // Before clicking the button the progress bar will invisible
            // so we have to change the visibility of the progress bar to visible
            // setting the progressbar visibility to visible
            progressBar.visibility = View.VISIBLE

            i = progressBar.progress

            Thread(Runnable {
                // this loop will run until the value of i becomes 99
                while (i < 100) {
                    i += 1
                    // Update the progress bar and display the current value
                    handler.post(Runnable {
                        progressBar.progress = i
                        // setting current progress to the textview
                        txtView!!.text = i.toString() + "/" + progressBar.max
                    })
                    try {
                        Thread.sleep(100)
                    } catch (e: InterruptedException) {
                        e.printStackTrace()
                    }
                }

                // setting the visibility of the progressbar to invisible
                // or you can use View.GONE instead of invisible
                // View.GONE will remove the progressbar
                progressBar.visibility = View.INVISIBLE

            }).start()
        }
    }
}

AndroidManifest.xml file

XML

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.geeksforgeeks.myfirstkotlinapp">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Output: