Dynamic ProgressBar in Kotlin

Android ProgressBar is user interface control that is used to show some kind of progress. For instance, loading of some page, downloading of some file or waiting for some event to complete.

In this article we will be discussing how to programmatically create a progress bar in Kotlin .

Firstly, we need to create a project in Android Studio. To do follow these steps:

• Click on File, then New and then New Project and give name whatever you like
• Then, select Kotlin language Support and click next button.
• Select minimum SDK, whatever you need.
• Select Empty activity and then click finish.

Modify activity_main.xml file

Second step is to design our layout page. Here, we will use the RelativeLayout to get the ProgressBar from the Kotlin file.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">


    <RelativeLayout
            android:id="@+id/layout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:layout_centerHorizontal="true"
            android:layout_above="@+id/button">

    </RelativeLayout>

    <Button
            android:id="@+id/button"
            android:layout_marginTop="100dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:text="Stop Loading"/>

</RelativeLayout>

Update the strings.xml file

<resources>
    <string name="app_name">DynamicProgressBarInKotlin</string>
</resources>

Create ProgressBar in MainActivity.kt file

Open app/src/main/java/yourPackageName/MainActivity.kt. In this file , we declare a variable progressBar to create the ProgressBar widget like this

       val progressBar = ProgressBar(this)
       //setting height and width of progressBar
       progressBar.layoutParams = LinearLayout.LayoutParams(
           ViewGroup.LayoutParams.WRAP_CONTENT,
           ViewGroup.LayoutParams.WRAP_CONTENT)

then add the widget in layout using this

val layout = findViewById(R.id.layout)
     // Add ProgressBar to our layout
     layout?.addView(progressBar)

package com.geeksforgeeks.myfirstkotlinapp

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.view.ViewGroup
import android.widget.Button
import android.widget.LinearLayout
import android.widget.ProgressBar
import android.widget.RelativeLayout

class MainActivity : AppCompatActivity() {

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


        val progressBar = ProgressBar(this)
        //setting height and width of progressBar
        progressBar.layoutParams = LinearLayout.LayoutParams(
            ViewGroup.LayoutParams.WRAP_CONTENT,
            ViewGroup.LayoutParams.WRAP_CONTENT)

        //accessing our relative layout where the progressBar will add up
        val layout = findViewById<RelativeLayout>(R.id.layout)
        // Add ProgressBar to our layout
        layout?.addView(progressBar)

        //accessing the button which will handle the events,
        // whether to show progressBar or not
        val button = findViewById<Button>(R.id.button)

        //set a click listener to show/hide progressBar added in RelativeLayout.
        button?.setOnClickListener {
            val visibility = if (progressBar.visibility == View.GONE){
                View.VISIBLE
            }else
                View.GONE
            progressBar.visibility = visibility

            //setting button text
            //if we click "stop loading" button, text of button will change
            // to "start loading.." and vice versa
            val btnText = if (progressBar.visibility == View.GONE)
                "START LOADING..."
            else
                "STOP LOADING"
            button.text = btnText
        }

    }
}

AndroidManifest.xml file

<?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>

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