Kotlin 멀티미디어 : 음악 듣기

1) 버튼을 이용한 음악 듣기
-------------------------------------------------------------------------------------
      activity_main.xml
-------------------------------------------------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/plyaButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="PLAY"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

------------------------------------------------------------------------------------
    MainActivity.kt
------------------------------------------------------------------------------------
class MainActivity : AppCompatActivity() {
    lateinit var playBTN: Button
    var mediaplayer : MediaPlayer?= null

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

        title = "음악 듣기"

        playBTN = findViewById(R.id.plyaButton)
        mediaplayer = MediaPlayer.create(this, R.raw.sample)

        //버튼을 클릭하면 mp3를 재생하도록 하자.
        playBTN.setOnClickListener {
            //재생할 파일을 준비한다.
            mediaplayer?.start()
        }
    }

    override fun onDestroy () {
        super.onDestroy ()
        mediaplayer?.release ()
    }
}

------------------------------------------------------------------------------------
    themes.xml
------------------------------------------------------------------------------------
<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Base.Theme.MultiMediaMusic" parent="Theme.AppCompat.Light">
        <!-- Customize your light theme here. -->
        <!-- <item name="colorPrimary">@color/my_light_primary</item> -->
    </style>

    <style name="Theme.MultiMediaMusic" parent="Base.Theme.MultiMediaMusic" />
</resources>

2) Switch를 이용한 음악 듣기
-------------------------------------------------------------------------------------
      activity_main.xml
-------------------------------------------------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Switch
        android:id="@+id/switch1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="음악듣기"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>

------------------------------------------------------------------------------------
    MainActivity.kt
------------------------------------------------------------------------------------
class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        title = "음악 듣기"

        var mPlayer: MediaPlayer
        mPlayer = MediaPlayer.create(this, R.raw.sample)

        var switch1 = findViewById<Switch>(R.id.switch1)
        switch1.setOnClickListener {
            if (switch1.isChecked == true)
                mPlayer.start()
            else
                mPlayer.stop()
        }
    }
}

------------------------------------------------------------------------------------
    themes.xml
------------------------------------------------------------------------------------
<resources xmlns:tools="http://schemas.android.com/tools">
    <!-- Base application theme. -->
    <style name="Base.Theme.MultiMediaSwitchMP3" parent="Theme.AppCompat.Light">
        <!-- Customize your light theme here. -->
        <!-- <item name="colorPrimary">@color/my_light_primary</item> -->
    </style>

    <style name="Theme.MultiMediaSwitchMP3" parent="Base.Theme.MultiMediaSwitchMP3" />
</resources>