Using wave file resource with MediaPlayer - android-studio

Question

I am trying to learn Kotlin and Android Studio by following a tutorial in Java that creates a MediaPlayer and plays a wave file. I am trying to adapt the code to Kotlin:
MainActivity.kt:
package com.example.debugwaveres
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.content.Context
import android.media.MediaPlayer
import android.view.View
//class MainActivity(private val context: Context) : AppCompatActivity() {
class MainActivity : AppCompatActivity() {
private var player: MediaPlayer? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
fun play(view: View) {
if (player == null) {
player = MediaPlayer.create(this, R.raw.metro1)
player?.setOnCompletionListener {
//stopPlayer()
}
}
player?.start()
}
}
The .wav resource R.raw.metro1 has been copied to the res/raw resource directory:
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:gravity="center"
android:orientation="vertical" >
<Button
android:layout_width="99dp"
android:layout_height="wrap_content"
android:onClick="play"
android:text="Play" />
</LinearLayout>
This compiles fine in Android Studio using an AVD with target Android 9.0, but when I click the play button I get an Exception java.io.IOException: Prepare failed :
04/07 19:36:36: Launching 'app' on Pixel 2 API 28.
$ adb shell am start -n "com.example.debugwaveres/com.example.debugwaveres.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Connected to process 11210 on device 'Pixel_2_API_28 [emulator-5554]'.
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
E/MediaPlayerNative: error (1, -2147483648)
D/MediaPlayer: create failed:
java.io.IOException: Prepare failed.: status=0x1
at android.media.MediaPlayer._prepare(Native Method)
at android.media.MediaPlayer.prepare(MediaPlayer.java:1282)
at android.media.MediaPlayer.create(MediaPlayer.java:983)
at android.media.MediaPlayer.create(MediaPlayer.java:954)
at com.example.debugwaveres.MainActivity.play(MainActivity.kt:18)
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:397)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

Answer 1

I tried your code. It works fine. But you can try like this:
fun play(view : View) {
if (player == null) {
player = MediaPlayer.create(this, R.raw.metro1)
player?.setOnCompletionListener {
//stopPlayer()
}
}
player?.setOnPreparedListener {
it.start()
}
}