SeekBar in Kotlin

Android seekBar is a modified version of progressBar that have draggable thumb in which a user can drag the thumb back and forth to set current progress value. We can use seekbar in our android device like Brightness control, volume control etc.

It is one of the important user Interface element which provides the option to select the integer values within the defined range like 1 to 100.

By dragging the thumb in SeekBar, we can slide back and forth to choose a value between minimum and maximum integer value which we defined using android:min and android:max attributes. respectively.

First we create a new project by following the below steps:

1. Click on File, then New => New Project.
2. After that include the Kotlin support and click on next.
3. Select the minimum SDK as per convenience and click next button.
4. Then select the Empty activity => next => finish.

Different Attributes of Android SeekBar Widget

XML Attributes	Description
android:id	Used to uniquely identify the control.
android:thumb	Used to set drawable to be used as thumb that can be moved back and forth.
android:thumbTint	Used to set tint to apply to the thumb.
android:min	Used to specify the minimum value.
android:max	Used to specify the maximum value.
android:progress	Used to specify the default progress value between 0 and 100.
android:progressDrawable	Used to specify drawable mode of the progress.
android:background	Used to set background of the specified view.
android:padding	Used to set the padding from left, right, top and bottom.

Modify activity_main.xml file

Here, we will add the Seekbar widget in LinearLayout and set its attributes like id, margin etc.

Kotlin

<?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:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical">

    <SeekBar
        android:id="@+id/seekBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="50dp"
        android:max="100"
        android:min="0" />
</LinearLayout>

Name of the application specify in the strings.xml file

Kotlin

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

MainActivity.kt file

In the file, we first declare a variable seek and call the seekbar from the xml file using the id.

val seek = findViewById(R.id.seekBar)

then, setOnClickListener to perform some action on the seekBar.

seek?.setOnSeekBarChangeListener

and display the toast message using

Toast.makeText(this@MainActivity,
   "Progress is: " + seek.progress + "%",
    Toast.LENGTH_SHORT).show()

Kotlin

package com.geeksforgeeks.myfirstkotlinapp

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.SeekBar
import android.widget.Toast

class MainActivity : AppCompatActivity() {

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

        val seek = findViewById<SeekBar>(R.id.seekBar)
        seek?.setOnSeekBarChangeListener(object :
            SeekBar.OnSeekBarChangeListener {
        override fun onProgressChanged(seek: SeekBar,
              progress: Int, fromUser: Boolean) {
          // write custom code for progress is changed
        }

        override fun onStartTrackingTouch(seek: SeekBar) {
            // write custom code for progress is started
        }

         override fun onStopTrackingTouch(seek: SeekBar) {
                // write custom code for progress is stopped
          Toast.makeText(this@MainActivity,
               "Progress is: " + seek.progress + "%",
                Toast.LENGTH_SHORT).show()
            }
        })
    }
}

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>

Run as emulator: