How to get a working vertical SeekBar in Android using Kotlin?

This example demonstrates how to listen for volume buttons in Android background service using kotlin.

Step 1 − Create a new project in Android Studio, go to File? New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

Example

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:padding="8dp"
   tools:context=".MainActivity">
   <SeekBar
      android:id="@+id/seekBar"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:rotation="270" />
   <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentTop="true"
      android:layout_centerHorizontal="true"
      android:text=""
   android:textSize="16sp" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

Example

import android.os.Bundle
import android.widget.SeekBar
import android.widget.SeekBar.OnSeekBarChangeListener
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
   lateinit var seekBar: SeekBar
   lateinit var textView: TextView
   var min = 0
   var max: Int = 100
   var current: Int = 50
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      textView = findViewById(R.id.textView)
      seekBar = findViewById(R.id.seekBar)
      seekBar.progress = max - min
      seekBar.progress = current - min
      textView.text = "" + current
      seekBar.setOnSeekBarChangeListener(object : OnSeekBarChangeListener {
         override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
            current = progress + min
            textView.text = "" + current
         }
         override fun onStartTrackingTouch(seekBar: SeekBar) {}
         override fun onStopTrackingTouch(seekBar: SeekBar) {}
      })
   }
}

Step 4 − Add the following code to src/SettingsContentObserver.kt

Example

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

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen