Audio in Android Studio stop button issue (Kotlin) - android-studio

Question

currently studying Kotlin and created an app that has 7 buttons (6 are playing certain audio and 7th is the stop button).When i play the first audio the audio starts and when i press stop button the audio stops, but the issue comes if i play the first audio and then the second and the third at same time , the stop button works only for the first audio and the rest keep playing at same time.Thanks for the help in advance.
This is the main activity & xml:
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var layout = findViewById<RelativeLayout>(R.id.parent_layout)
val animation = layout.background as AnimationDrawable?
animation?.setEnterFadeDuration(3000)
animation?.setExitFadeDuration(1000)
animation?.start()
}
fun PlaySoundOnButtons(view: View){
val sound = view as Button
val mediaPlayer = MediaPlayer.create(this#MainActivity,resources.getIdentifier(sound.tag as String,"raw",packageName))
mediaPlayer.start()
if (mediaPlayer.isPlaying) {
sound.setBackgroundColor(Color.RED)
}
mediaPlayer.setOnCompletionListener { sound.setBackgroundColor(Color.WHITE)
}
val stopSound = findViewById(R.id.stop_btn) as Button
stopSound.setOnClickListener {
mediaPlayer.stop()
if (mediaPlayer.isPlaying){
mediaPlayer.stop()
}
}
}
}
**XML File**:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/parent_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/mix_colours"
tools:context=".MainActivity">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="30dp"
android:layout_marginStart="20dp"
android:layout_marginLeft="20dp"
android:layout_marginTop="20dp"
android:layout_marginEnd="20dp"
android:layout_marginRight="20dp"
android:layout_marginBottom="20dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<Button
android:id="#+id/button4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:onClick="PlaySoundOnButtons"
android:tag="one"
android:text="Hip Hop"
android:textColor="#color/black"
android:textSize="20sp"
app:backgroundTint="#color/white" />
<Button
android:id="#+id/button5"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:onClick="PlaySoundOnButtons"
android:tag="two"
android:text="Rap"
android:textColor="#color/black"
android:textSize="20sp"
app:backgroundTint="#color/white" />
<Button
android:id="#+id/button6"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:onClick="PlaySoundOnButtons"
android:tag="three"
android:text="Jazz"
android:textColor="#color/black"
android:textSize="20sp"
app:backgroundTint="#color/white" />
<Button
android:id="#+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:onClick="PlaySoundOnButtons"
android:tag="four"
android:text="Agressive rap"
android:textColor="#color/black"
android:textSize="20sp"
app:backgroundTint="#color/white" />
<Button
android:id="#+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:onClick="PlaySoundOnButtons"
android:tag="five"
android:text="Old school"
android:textColor="#color/black"
android:textSize="20sp"
app:backgroundTint="#color/white" />
<Button
android:id="#+id/button3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:onClick="PlaySoundOnButtons"
android:tag="six"
android:text="Underground rap"
android:textColor="#color/black"
android:textSize="20sp"
app:backgroundTint="#color/white" />
<Button
android:id="#+id/stop_btn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Stop"
android:soundEffectsEnabled="false"
app:backgroundTint="#color/design_default_color_error" />
</LinearLayout>
</ScrollView>
</RelativeLayout>```

Answer 1

if you want playing single audio you need declare the mediaPlayer outside of your click function and the function of stop button to onCreate
lateinit var mediaPlayer:MediaPlayer
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var layout = findViewById<RelativeLayout>(R.id.parent_layout)
val animation = layout.background as AnimationDrawable?
animation?.setEnterFadeDuration(3000)
animation?.setExitFadeDuration(1000)
animation?.start()
val stopSound = findViewById(R.id.stop_btn) as Button
stopSound.setOnClickListener {
if (::mediaPlayer.isInitialized && mediaPlayer.isPlaying){
mediaPlayer.stop()
}
}
}
fun PlaySoundOnButtons(view: View){
val sound = view as Button
if (::mediaPlayer.isInitialized && mediaPlayer.isPlaying){
mediaPlayer.stop()
}
mediaPlayer = MediaPlayer.create(this#MainActivity,resources.getIdentifier(sound.tag as String,"raw",packageName))
mediaPlayer.start()
if (mediaPlayer.isPlaying) {
sound.setBackgroundColor(Color.RED)
}
mediaPlayer.setOnCompletionListener {
sound.setBackgroundColor(Color.WHITE)
}
}

Answer 2

All your buttons call the same click listener, which creates a new MediaPlayer, starts it playing, and then sets the stop button to stop that MediaPlayer instance.
So the problem is you have one stop button, and it can only stop the last media player that was assigned to it. Every time a new click happens a new player is created, and the stop button forgets whatever player it was handling before. Even if you click the same button twice.
You need to keep track of all your current MediaPlayer instances, so your stop button can call stop() on all of them. And really, you need to keep track of them anyway, so you can call release() and free up resources
When done with the MediaPlayer, you should call release(), to free the resources. If not released, too many MediaPlayer instances will result in an exception.
You might want to consider keeping a map of them, and when your click listener is called, try to get the media player associated with the view that was clicked, creating a new one for that view if one doesn't exist. Then you can iterate over them all to stop (and maybe call release on them while you're at it)