MediaPlayer class to implement a basic Audio Player in an Android Kotlin app?

This example demonstrates how to implement a MediaPlayer class to implement a basic Audio Player in an Android Kotlin app.

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.

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingLeft="10dp"    android:paddingRight="10dp">    <TextView       android:id="@+id/textView"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_marginTop="30dp"       android:text="Now Playing: "       android:textAppearance="?android:attr/textAppearanceMedium"       android:textColor="@android:color/holo_red_dark"       android:textSize="16sp"       android:textStyle="bold|italic" />    <TextView       android:id="@+id/txtSongName"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignBaseline="@+id/textView"       android:layout_toEndOf="@+id/textView"       android:textColor="@android:color/background_dark"       android:textSize="16sp"       android:textStyle="bold|italic" />    <ImageButton       android:id="@+id/btnBackward"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_centerInParent="true"       android:src="@drawable/ic_back" />    <ImageButton       android:id="@+id/btnPlay"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignTop="@+id/btnBackward"       android:layout_marginStart="10dp"       android:layout_toEndOf="@+id/btnBackward"       android:src="@drawable/ic_play" />    <ImageButton       android:id="@+id/btnPause"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignTop="@+id/btnPlay"       android:layout_marginStart="10dp"       android:layout_toEndOf="@+id/btnPlay"       android:src="@drawable/ic_pause" />    <ImageButton       android:id="@+id/btnForward"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignTop="@+id/btnPause"       android:layout_marginStart="10dp"       android:layout_toEndOf="@+id/btnPause"       android:contentDescription="@+id/imageButton3"       android:src="@drawable/ic_forward" />    <TextView       android:id="@+id/txtStartTime"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignTop="@+id/seekBar"       android:text="0 min, 0 sec" />    <SeekBar       android:id="@+id/seekBar"       android:layout_width="match_parent"       android:layout_height="wrap_content"       android:layout_above="@+id/btnBackward"       android:layout_toStartOf="@+id/txtSongTime"       android:layout_toEndOf="@+id/txtStartTime" />    <TextView       android:id="@+id/txtSongTime"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_alignTop="@+id/seekBar"       android:layout_toEndOf="@+id/btnForward"       android:text="0 min, 0 sec " /> </RelativeLayout>

Step 3 − Add the following code to MainActivity.kt

import android.media.MediaPlayer import android.os.Bundle import android.os.Handler import android.widget.ImageButton import android.widget.SeekBar import android.widget.TextView import android.widget.Toast import androidx.appcompat.app.AppCompatActivity import kotlinx.android.synthetic.main.activity_main.* import java.util.concurrent.TimeUnit class MainActivity : AppCompatActivity() {    lateinit var forwardBtn: ImageButton    lateinit var backwardBtn: ImageButton    lateinit var pauseBtn: ImageButton    lateinit var playBtn: ImageButton    lateinit var mediaPlayer: MediaPlayer    private lateinit var songName: TextView    private lateinit var startTime: TextView    private lateinit var songTime: TextView    private lateinit var seekBar: SeekBar    private var handler: Handler = Handler()    private var onTime: Int = 0    private var playTime: Int = 0    private var endTime: Int = 0    private var forwardTime: Int = 5000    private var backwardTime: Int = 5000    override fun onCreate(savedInstanceState: Bundle?) {       super.onCreate(savedInstanceState)       setContentView(R.layout.activity_main)       title = "KotlinApp"       backwardBtn = findViewById(R.id.btnBackward)       forwardBtn = findViewById(R.id.btnForward)       playBtn = findViewById(R.id.btnPlay)       pauseBtn = findViewById(R.id.btnPause)       songName = findViewById(R.id.txtSongName)       startTime = findViewById(R.id.txtStartTime)       songTime = findViewById(R.id.txtSongTime)       songName.text = "SpeakerBox - Fast & Furious"       mediaPlayer = MediaPlayer.create(this, R.raw.fast_and_furious)       seekBar = findViewById(R.id.seekBar)       seekBar.isClickable = false       pauseBtn.isEnabled = true       playBtn.setOnClickListener {          Toast.makeText(this, "Playing Audio", Toast.LENGTH_SHORT).show()          mediaPlayer.start()          endTime = mediaPlayer.duration          playTime = mediaPlayer.currentPosition          seekBar.max = endTime          onTime = 1          songTime.text = String.format(             "%d min, %d sec",             TimeUnit.MILLISECONDS.toMinutes(endTime.toLong()),             TimeUnit.MILLISECONDS.toSeconds(endTime.toLong()) -             TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(endTime.toLong()))          )          startTime.text = String.format(             "%d min, %d sec",             TimeUnit.MILLISECONDS.toMinutes(playTime.toLong()),             TimeUnit.MILLISECONDS.toSeconds(playTime.toLong()) -             TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(playTime.toLong()))          )          seekBar.progress = playTime          handler.postDelayed(updateSongTime, 100)          pauseBtn.isEnabled = true          playBtn.isEnabled = false       }       btnPause.setOnClickListener {          mediaPlayer.pause()          pauseBtn.isEnabled = false          playBtn.isEnabled = true          Toast.makeText(applicationContext, "Audio Paused", Toast.LENGTH_SHORT).show()       }       btnForward.setOnClickListener {          if ((playTime + forwardTime) <= endTime) {             playTime += forwardTime             mediaPlayer.seekTo(playTime)          }           else {             Toast.makeText(                applicationContext,                "Cannot jump forward 5 seconds",                Toast.LENGTH_SHORT             ).show()          }          if (!playBtn.isEnabled) {             playBtn.isEnabled = true          }       }       btnBackward.setOnClickListener {          if ((playTime - backwardTime) > 0) {             playTime -= backwardTime             mediaPlayer.seekTo(playTime)          }          else {             Toast.makeText(                applicationContext,                "Cannot jump backward 5 seconds",                Toast.LENGTH_SHORT             ).show()          }          if (!playBtn.isEnabled) {             playBtn.isEnabled = true          }       }    }    private val updateSongTime = object : Runnable {       override fun run() {          playTime = mediaPlayer.currentPosition          startTime.text = String.format(             "%d min, %d sec", TimeUnit.MILLISECONDS.toMinutes(playTime.toLong()             (TimeUnit.MILLISECONDS.toSeconds(playTime.toLong()) - TimeUnit.MINUTES.toSeconds (TimeUnit.MILLISECONDS.toMinutes(                   playTime.toLong()                )             ))          )          seekBar.progress = playTime          handler.postDelayed(this, 100)       }    } }

Step 4 − Add the following code to androidManifest.xml

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

Click here to download the project code.