问如何在Kotlin中为Android MediaPlayer设置新的音频数据源

EN

class MainActivity :
AppCompatActivity(),
MediaPlayer.OnPreparedListener{


override fun onCreate(savedInstanceState: Bundle?) {

    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val btnMaintain = findViewById<Button>(R.id.btnMaintain)
    val mediaPlayer = MediaPlayer.create(this, R.raw.fifo50)
    mediaPlayer.stop()
    mediaPlayer.reset()
    mediaPlayer.setAudioAttributes(
        AudioAttributes.Builder()
            .setUsage(AudioAttributes.USAGE_MEDIA)
            .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
            .build()
                )
    mediaPlayer.setDataSource("android.resource://" + this.packageName + "/raw/maintain_speed")
    Toast.makeText(this, "Preparing Media Player", Toast.LENGTH_SHORT).show()
    mediaPlayer.setOnPreparedListener(this)
    mediaPlayer.prepareAsync()
    Toast.makeText(this, "Asynchronous preparation of Media Player started", Toast.LENGTH_SHORT).show()

    btnMaintain.setOnClickListener() {
        mediaPlayer.isLooping = true
        mediaPlayer.start()
    }
}

override fun onPrepared(p0: MediaPlayer) {
    Toast.makeText(this, "Media Player prepared!", Toast.LENGTH_SHORT).show()
}