Android Indeterminate ProgressBar – Kotlin Example

Android Indeterminate ProgressBar – Kotlin Example

Android Indeterminate ProgressBar – Kotlin Example : In this Android Tutorial, we shall learn to indicate the progress of a task whose progress cannot be tracked. Here we shall not indicate any specific numbers for the progress, but with an indefinite progressing view. An example task could be page loading, the progress is indefinite, but we have to let the user know that page loading task is happening, and so the ProgressBar used is in Indefinite mode.

Usually indefinite ProgressBar is used in such a way that initially it is hidden. When the task is started by an event or some other means, ProgressBar is shown. And finally when the task is completed, the ProgressBar is again hidden.

Indeterminate is the default mode of a ProgressBar and most importantly do not mention any progress for the view in layout xml file.

In this tutorial, we shall mimic the indeterminate task with a Runnable Thread using a long running while loop.

Following are the details of the Android Application we created for this example.

Application Name	ProgressBarIndEx
Company name	tutorialkart.com
Minimum SDK	API 21: Android 5.0 (Lollipop)
Activity	Empty Activity

Create an Android Application with Kotlin Support with above details and keeping rest to default. Replace activity_main.xml and MainActivity.kt with the following content.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center"
    tools:context="com.tutorialkart.progressbarindex.MainActivity">

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Do some stuff" />

    <ProgressBar
        android:id="@+id/progressBar1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp"
        android:visibility="gone"/>

</LinearLayout>

MainActivity.kt

package com.tutorialkart.progressbarindex

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.view.View
import android.widget.ProgressBar
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity() {

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

        // get the references from layout file
        val btnStartProgress = this.button1
        val progressBar: ProgressBar = this.progressBar1

        // when button is clicked, start the task
        btnStartProgress.setOnClickListener { v ->

            // task is run on a thread
            Thread(Runnable {
                // dummy thread mimicking some operation whose progress cannot be tracked

                // display the indefinite progressbar
                this@MainActivity.runOnUiThread(java.lang.Runnable {
                    progressBar.visibility = View.VISIBLE
                })

                // performing some dummy time taking operation
                try {
                    var i=0;
                    while(i<Int.MAX_VALUE){
                        i++
                    }
                } catch (e: InterruptedException) {
                    e.printStackTrace()
                }

                // when the task is completed, make progressBar gone
                this@MainActivity.runOnUiThread(java.lang.Runnable {
                    progressBar.visibility = View.GONE
                })
            }).start()
        }
    }
}