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How to adjust volume during audio playback using MediaPlayer in Kotlin Android

How to adjust volume during audio playback using MediaPlayer in Kotlin Android.

Here's a step-by-step tutorial on how to adjust volume during audio playback using MediaPlayer in Kotlin for Android.

Step 1: Set up the project​

  • Create a new Android project in Android Studio.
  • Add the necessary permissions in the AndroidManifest.xml file to access audio settings:
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

Step 2: Add MediaPlayer to the project​

  • In the app-level build.gradle file, add the MediaPlayer dependency:
implementation 'androidx.media:media:1.4.3'

Step 3: Initialize the MediaPlayer​

  • Create an instance of MediaPlayer in your activity or fragment:
private lateinit var mediaPlayer: MediaPlayer

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

    mediaPlayer = MediaPlayer()
}

Step 4: Prepare the audio file​

  • Place the audio file you want to play in the res/raw directory.
  • Prepare the audio file for playback:
mediaPlayer.setDataSource(applicationContext, Uri.parse("android.resource://$packageName/${R.raw.audio_file}"))
mediaPlayer.prepare()

Step 5: Adjust the volume​

  • To adjust the volume during audio playback, you can use the setVolume method of the MediaPlayer class. The method takes two parameters: leftVolume and rightVolume, both ranging from 0.0 to 1.0.
  • For example, to set the volume to half of the maximum:
mediaPlayer.setVolume(0.5f, 0.5f)

Step 6: Control volume using SeekBar​

  • Add a SeekBar widget to your layout file (activity_main.xml) to control the volume:
<SeekBar
    android:id="@+id/volumeSeekBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:max="100"
    android:progress="50" />
  • In your activity or fragment, initialize the SeekBar and set a listener to update the volume:
private lateinit var volumeSeekBar: SeekBar

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

    mediaPlayer = MediaPlayer()

    volumeSeekBar = findViewById(R.id.volumeSeekBar)
    volumeSeekBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
        override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
            val volume = progress / 100f
            mediaPlayer.setVolume(volume, volume)
        }

        override fun onStartTrackingTouch(seekBar: SeekBar?) {}

        override fun onStopTrackingTouch(seekBar: SeekBar?) {}
    })
}

Step 7: Play and stop audio​

  • Implement the play and stop functionality using buttons or other UI elements:
fun playAudio() {
    mediaPlayer.start()
}

fun stopAudio() {
    mediaPlayer.stop()
    mediaPlayer.prepare()
}

That's it! You now have a functioning audio playback system with volume control using MediaPlayer in Kotlin for Android.