android - Set media volume programmatically

activity_main.xml

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout     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/root_layout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:padding="16dp"     android:orientation="vertical"     android:background="#d0e9ec"     >     <TextView         android:id="@+id/tv_stats"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:textStyle="bold"         android:textSize="25sp"         />     <Button         android:id="@+id/btn_media"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Set Media Volume"         /> </LinearLayout> 

MainActivity.java

 package com.cfsuman.me.androidcodesnippets;  import android.app.Activity; import android.content.Context; import android.media.AudioManager; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.LinearLayout; import android.widget.TextView;  import java.util.Random;   public class MainActivity extends AppCompatActivity {     private Context mContext;     private Activity mActivity;      private LinearLayout mRootLayout;     private Button mBtnSetMediaVolume;     private TextView mTVStats;      private AudioManager mAudioManager;     private Random mRandom = new Random();      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          // Get the application context         mContext = getApplicationContext();         mActivity = MainActivity.this;          // Get the widget reference from xml layout         mRootLayout = findViewById(R.id.root_layout);         mBtnSetMediaVolume = findViewById(R.id.btn_media);         mTVStats = findViewById(R.id.tv_stats);          /*             AudioManager                 AudioManager provides access to volume and ringer mode control.                  Instances of this class must be obtained using                 Context.getSystemService(Class) with the argument AudioManager.class or                 Context.getSystemService(String) with the argument Context.AUDIO_SERVICE.         */          // Get the audio manager instance         mAudioManager = (AudioManager) getSystemService(AUDIO_SERVICE);          // Set click listener for media button         mBtnSetMediaVolume.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 /*                     STREAM_MUSIC                         Used to identify the volume of audio streams for music playback                 */                  /*                     int getStreamVolume (int streamType)                         Returns the current volume index for a particular stream.                      Parameters                         streamType int : The stream type whose volume index is returned.                      Returns                         int : The current volume index for the stream.                 */                 int media_current_volume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);                  /*                     int getStreamMaxVolume (int streamType)                         Returns the maximum volume index for a particular stream.                      Parameters                         streamType int : The stream type whose maximum volume index is returned.                      Returns                         int : The maximum valid volume index for the stream.                 */                 int media_max_volume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);                  // Get a random number between a specified range                 int random_volume = mRandom.nextInt(((media_max_volume - 0) + 1) + 0);                  /*                     void setStreamVolume (int streamType, int index, int flags)                         Sets the volume index for a particular stream.                          This method has no effect if the device implements a fixed volume policy                         as indicated by isVolumeFixed().                          From N onward, volume adjustments that would toggle Do Not Disturb are not                         allowed unless the app has been granted Do Not Disturb Access.                         See isNotificationPolicyAccessGranted().                      Parameters                         streamType int : The stream whose volume index should be set.                         index int : The volume index to set. See getStreamMaxVolume(int) for the largest valid value.                           flags int : One or more flags.                 */                 /*                     int FLAG_SHOW_UI                         Show a toast containing the current volume.                 */                 // Set media volume level                 mAudioManager.setStreamVolume(                         AudioManager.STREAM_MUSIC, // Stream type                         random_volume, // Index                         AudioManager.FLAG_SHOW_UI // Flags                 );                  // Display the media volume isu on text view                 mTVStats.setText("Media Current Volume : " + media_current_volume);                 mTVStats.append("\nMedia Max Volume : " + media_max_volume);                 mTVStats.append("\nMedia New Volume : " + random_volume);             }         });     } }