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.
Step by Step Implementation
Step 1: Create a new project
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio.
Step 2: Add ProgressBar Widget in activity_main.xml file
Navigate to app > res > layout > activity_main.xml and add a Progress bar and Button to show and hide the progress bar.
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/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white"
tools:context=".MainActivity">
<!--on below line we are creating a progress bar-->
<LinearLayout
android:id="@+id/layout"
android:layout_width="100dp"
android:layout_height="100dp"
android:orientation="vertical"
android:gravity="center"
app:layout_constraintBottom_toTopOf="@+id/button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_chainStyle="packed"/>
<!--on below line we are creating a button-->
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="32dp"
android:text="Show/Hide"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/layout" />
</androidx.constraintlayout.widget.ConstraintLayout>
Design UI:
Step 3: Create ProgressBar in MainActivity.kt file
Navigate to app > src > main > java > {package-name} > MainActivity.kt.
In this file, we will declare a variable progressBar to create the ProgressBar widget
val progressBar = ProgressBar(this)
progressBar.layoutParams = LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT
)
then add the widget in layout
val layout: LinearLayout = findViewById(R.id.layout)
layout.addView(progressBar)
MainActivity.kt:
package org.geeksforgeeks.demo
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 androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
private var isProgressVisible = false
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// initializing our variables
val showProgressBtn: Button = findViewById(R.id.button)
val layout: LinearLayout = findViewById(R.id.layout)
// creating a progress bar
val progressBar = ProgressBar(this)
progressBar.layoutParams = LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT)
// Add ProgressBar to our layout
layout.addView(progressBar)
// set visibility off by default
progressBar.visibility = View.GONE
showProgressBtn.setOnClickListener {
// checking if progress bar is already visible.
if (isProgressVisible) {
progressBar.visibility = View.GONE
isProgressVisible = false
} else {
progressBar.visibility = View.VISIBLE
isProgressVisible = true
}
}
}
}