Implement DeviceComponent of SimpleExoPlayer

PiperOrigin-RevId: 305460260

RELEASENOTES.md

@@ -63,6 +63,8 @@
     *   Update `CachedContentIndex` to use `SecureRandom` for generating the
     *   Update `CachedContentIndex` to use `SecureRandom` for generating the
         initialization vector used to encrypt the cache contents.
         initialization vector used to encrypt the cache contents.
     *   Remove deprecated members in `DefaultTrackSelector`.
     *   Remove deprecated members in `DefaultTrackSelector`.
+    *   Add `Player.DeviceComponent` and implement it for `SimpleExoPlayer` so
+        that the device volume can be controlled by player.
 *   Text:
 *   Text:
     *   Parse `<ruby>` and `<rt>` tags in WebVTT subtitles (rendering is coming
     *   Parse `<ruby>` and `<rt>` tags in WebVTT subtitles (rendering is coming
         later).
         later).

library/core/src/androidTest/java/com/google/android/exoplayer2/StreamVolumeManagerTest.java

+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2;
+
+import static com.google.common.truth.Truth.assertThat;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+
+import android.content.Context;
+import android.media.AudioManager;
+import android.os.Handler;
+import android.os.Looper;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SdkSuppress;
+import com.google.android.exoplayer2.testutil.DummyMainThread;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+/** Unit tests for {@link StreamVolumeManager}. */
+@RunWith(AndroidJUnit4.class)
+public class StreamVolumeManagerTest {
+
+  private static final long TIMEOUT_MS = 1_000;
+
+  private AudioManager audioManager;
+  private TestListener testListener;
+  private DummyMainThread testThread;
+  private StreamVolumeManager streamVolumeManager;
+
+  @Before
+  public void setUp() {
+    Context context = ApplicationProvider.getApplicationContext();
+
+    audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+    testListener = new TestListener();
+
+    testThread = new DummyMainThread();
+    testThread.runOnMainThread(
+        () ->
+            streamVolumeManager =
+                new StreamVolumeManager(context, new Handler(Looper.myLooper()), testListener));
+  }
+
+  @After
+  public void tearDown() {
+    testThread.runOnMainThread(() -> streamVolumeManager.release());
+    testThread.release();
+  }
+
+  @Test
+  @SdkSuppress(minSdkVersion = 28)
+  public void getMinVolume_returnsStreamMinVolume() {
+    testThread.runOnMainThread(
+        () -> {
+          int streamMinVolume = audioManager.getStreamMinVolume(C.STREAM_TYPE_DEFAULT);
+          assertThat(streamVolumeManager.getMinVolume()).isEqualTo(streamMinVolume);
+        });
+  }
+
+  @Test
+  public void getMaxVolume_returnsStreamMaxVolume() {
+    testThread.runOnMainThread(
+        () -> {
+          int streamMaxVolume = audioManager.getStreamMaxVolume(C.STREAM_TYPE_DEFAULT);
+          assertThat(streamVolumeManager.getMaxVolume()).isEqualTo(streamMaxVolume);
+        });
+  }
+
+  @Test
+  public void getVolume_returnsStreamVolume() {
+    testThread.runOnMainThread(
+        () -> {
+          int streamVolume = audioManager.getStreamVolume(C.STREAM_TYPE_DEFAULT);
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(streamVolume);
+        });
+  }
+
+  @Test
+  public void setVolume_changesStreamVolume() {
+    testThread.runOnMainThread(
+        () -> {
+          int minVolume = streamVolumeManager.getMinVolume();
+          int maxVolume = streamVolumeManager.getMaxVolume();
+          if (minVolume == maxVolume) {
+            return;
+          }
+
+          int oldVolume = streamVolumeManager.getVolume();
+          int targetVolume = oldVolume == maxVolume ? minVolume : maxVolume;
+
+          streamVolumeManager.setVolume(targetVolume);
+
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(targetVolume);
+          assertThat(testListener.lastStreamVolume).isEqualTo(targetVolume);
+          assertThat(audioManager.getStreamVolume(C.STREAM_TYPE_DEFAULT)).isEqualTo(targetVolume);
+        });
+  }
+
+  @Test
+  public void setVolume_withOutOfRange_isIgnored() {
+    testThread.runOnMainThread(
+        () -> {
+          int maxVolume = streamVolumeManager.getMaxVolume();
+          int minVolume = streamVolumeManager.getMinVolume();
+          int oldVolume = streamVolumeManager.getVolume();
+
+          streamVolumeManager.setVolume(maxVolume + 1);
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(oldVolume);
+
+          streamVolumeManager.setVolume(minVolume - 1);
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(oldVolume);
+        });
+  }
+
+  @Test
+  public void increaseVolume_increasesStreamVolumeByOne() {
+    testThread.runOnMainThread(
+        () -> {
+          int minVolume = streamVolumeManager.getMinVolume();
+          int maxVolume = streamVolumeManager.getMaxVolume();
+          if (minVolume == maxVolume) {
+            return;
+          }
+
+          streamVolumeManager.setVolume(minVolume);
+          int targetVolume = minVolume + 1;
+
+          streamVolumeManager.increaseVolume();
+
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(targetVolume);
+          assertThat(testListener.lastStreamVolume).isEqualTo(targetVolume);
+          assertThat(audioManager.getStreamVolume(C.STREAM_TYPE_DEFAULT)).isEqualTo(targetVolume);
+        });
+  }
+
+  @Test
+  public void increaseVolume_onMaxVolume_isIgnored() {
+    testThread.runOnMainThread(
+        () -> {
+          int maxVolume = streamVolumeManager.getMaxVolume();
+
+          streamVolumeManager.setVolume(maxVolume);
+          streamVolumeManager.increaseVolume();
+
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(maxVolume);
+        });
+  }
+
+  @Test
+  public void decreaseVolume_decreasesStreamVolumeByOne() {
+    testThread.runOnMainThread(
+        () -> {
+          int minVolume = streamVolumeManager.getMinVolume();
+          int maxVolume = streamVolumeManager.getMaxVolume();
+          if (minVolume == maxVolume) {
+            return;
+          }
+
+          streamVolumeManager.setVolume(maxVolume);
+          int targetVolume = maxVolume - 1;
+
+          streamVolumeManager.decreaseVolume();
+
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(targetVolume);
+          assertThat(testListener.lastStreamVolume).isEqualTo(targetVolume);
+          assertThat(audioManager.getStreamVolume(C.STREAM_TYPE_DEFAULT)).isEqualTo(targetVolume);
+        });
+  }
+
+  @Test
+  public void decreaseVolume_onMinVolume_isIgnored() {
+    testThread.runOnMainThread(
+        () -> {
+          int minVolume = streamVolumeManager.getMinVolume();
+
+          streamVolumeManager.setVolume(minVolume);
+          streamVolumeManager.decreaseVolume();
+
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(minVolume);
+        });
+  }
+
+  @Test
+  public void setStreamType_notifiesStreamTypeAndVolume() {
+    testThread.runOnMainThread(
+        () -> {
+          int minVolume = streamVolumeManager.getMinVolume();
+          int maxVolume = streamVolumeManager.getMaxVolume();
+          if (minVolume == maxVolume) {
+            return;
+          }
+
+          int testStreamType = C.STREAM_TYPE_ALARM;
+          int testStreamVolume = audioManager.getStreamVolume(testStreamType);
+
+          int oldVolume = streamVolumeManager.getVolume();
+          if (oldVolume == testStreamVolume) {
+            int differentVolume = oldVolume == minVolume ? maxVolume : minVolume;
+            streamVolumeManager.setVolume(differentVolume);
+          }
+
+          streamVolumeManager.setStreamType(testStreamType);
+
+          assertThat(testListener.lastStreamType).isEqualTo(testStreamType);
+          assertThat(testListener.lastStreamVolume).isEqualTo(testStreamVolume);
+          assertThat(streamVolumeManager.getVolume()).isEqualTo(testStreamVolume);
+        });
+  }
+
+  @Test
+  public void onStreamVolumeChanged_isCalled_whenAudioManagerChangesIt() throws Exception {
+    AtomicInteger targetVolumeRef = new AtomicInteger();
+    testThread.runOnMainThread(
+        () -> {
+          int minVolume = streamVolumeManager.getMinVolume();
+          int maxVolume = streamVolumeManager.getMaxVolume();
+          if (minVolume == maxVolume) {
+            return;
+          }
+
+          int oldVolume = streamVolumeManager.getVolume();
+          int targetVolume = oldVolume == maxVolume ? minVolume : maxVolume;
+          targetVolumeRef.set(targetVolume);
+
+          audioManager.setStreamVolume(C.STREAM_TYPE_DEFAULT, targetVolume, /* flags= */ 0);
+        });
+
+    testListener.onStreamVolumeChangedLatch.await(TIMEOUT_MS, MILLISECONDS);
+    assertThat(testListener.lastStreamVolume).isEqualTo(targetVolumeRef.get());
+  }
+
+  private static class TestListener implements StreamVolumeManager.Listener {
+
+    @C.StreamType private int lastStreamType;
+    private int lastStreamVolume;
+    public final CountDownLatch onStreamVolumeChangedLatch;
+
+    public TestListener() {
+      onStreamVolumeChangedLatch = new CountDownLatch(1);
+    }
+
+    @Override
+    public void onStreamTypeChanged(@C.StreamType int streamType) {
+      lastStreamType = streamType;
+    }
+
+    @Override
+    public void onStreamVolumeChanged(int streamVolume) {
+      lastStreamVolume = streamVolume;
+      onStreamVolumeChangedLatch.countDown();
+    }
+  }
+}

library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java

@@ -36,6 +36,8 @@ import com.google.android.exoplayer2.audio.AudioListener;
 import com.google.android.exoplayer2.audio.AudioRendererEventListener;
 import com.google.android.exoplayer2.audio.AudioRendererEventListener;
 import com.google.android.exoplayer2.audio.AuxEffectInfo;
 import com.google.android.exoplayer2.audio.AuxEffectInfo;
 import com.google.android.exoplayer2.decoder.DecoderCounters;
 import com.google.android.exoplayer2.decoder.DecoderCounters;
+import com.google.android.exoplayer2.device.DeviceInfo;
+import com.google.android.exoplayer2.device.DeviceListener;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataOutput;
 import com.google.android.exoplayer2.metadata.MetadataOutput;
 import com.google.android.exoplayer2.source.DefaultMediaSourceFactory;
 import com.google.android.exoplayer2.source.DefaultMediaSourceFactory;
@@ -73,7 +75,8 @@ public class SimpleExoPlayer extends BasePlayer
         Player.AudioComponent,
         Player.AudioComponent,
         Player.VideoComponent,
         Player.VideoComponent,
         Player.TextComponent,
         Player.TextComponent,
-        Player.MetadataComponent {
+        Player.MetadataComponent,
+        Player.DeviceComponent {
 
 
   /** @deprecated Use {@link com.google.android.exoplayer2.video.VideoListener}. */
   /** @deprecated Use {@link com.google.android.exoplayer2.video.VideoListener}. */
   @Deprecated
   @Deprecated
@@ -330,6 +333,7 @@ public class SimpleExoPlayer extends BasePlayer
   private final CopyOnWriteArraySet<AudioListener> audioListeners;
   private final CopyOnWriteArraySet<AudioListener> audioListeners;
   private final CopyOnWriteArraySet<TextOutput> textOutputs;
   private final CopyOnWriteArraySet<TextOutput> textOutputs;
   private final CopyOnWriteArraySet<MetadataOutput> metadataOutputs;
   private final CopyOnWriteArraySet<MetadataOutput> metadataOutputs;
+  private final CopyOnWriteArraySet<DeviceListener> deviceListeners;
   private final CopyOnWriteArraySet<VideoRendererEventListener> videoDebugListeners;
   private final CopyOnWriteArraySet<VideoRendererEventListener> videoDebugListeners;
   private final CopyOnWriteArraySet<AudioRendererEventListener> audioDebugListeners;
   private final CopyOnWriteArraySet<AudioRendererEventListener> audioDebugListeners;
   private final BandwidthMeter bandwidthMeter;
   private final BandwidthMeter bandwidthMeter;
@@ -337,6 +341,7 @@ public class SimpleExoPlayer extends BasePlayer
 
 
   private final AudioBecomingNoisyManager audioBecomingNoisyManager;
   private final AudioBecomingNoisyManager audioBecomingNoisyManager;
   private final AudioFocusManager audioFocusManager;
   private final AudioFocusManager audioFocusManager;
+  private final StreamVolumeManager streamVolumeManager;
   private final WakeLockManager wakeLockManager;
   private final WakeLockManager wakeLockManager;
   private final WifiLockManager wifiLockManager;
   private final WifiLockManager wifiLockManager;
 
 
@@ -364,6 +369,7 @@ public class SimpleExoPlayer extends BasePlayer
   @Nullable private PriorityTaskManager priorityTaskManager;
   @Nullable private PriorityTaskManager priorityTaskManager;
   private boolean isPriorityTaskManagerRegistered;
   private boolean isPriorityTaskManagerRegistered;
   private boolean playerReleased;
   private boolean playerReleased;
+  private DeviceInfo deviceInfo;
 
 
   /** @param builder The {@link Builder} to obtain all construction parameters. */
   /** @param builder The {@link Builder} to obtain all construction parameters. */
   protected SimpleExoPlayer(Builder builder) {
   protected SimpleExoPlayer(Builder builder) {
@@ -414,6 +420,7 @@ public class SimpleExoPlayer extends BasePlayer
     audioListeners = new CopyOnWriteArraySet<>();
     audioListeners = new CopyOnWriteArraySet<>();
     textOutputs = new CopyOnWriteArraySet<>();
     textOutputs = new CopyOnWriteArraySet<>();
     metadataOutputs = new CopyOnWriteArraySet<>();
     metadataOutputs = new CopyOnWriteArraySet<>();
+    deviceListeners = new CopyOnWriteArraySet<>();
     videoDebugListeners = new CopyOnWriteArraySet<>();
     videoDebugListeners = new CopyOnWriteArraySet<>();
     audioDebugListeners = new CopyOnWriteArraySet<>();
     audioDebugListeners = new CopyOnWriteArraySet<>();
     eventHandler = new Handler(looper);
     eventHandler = new Handler(looper);
@@ -456,8 +463,10 @@ public class SimpleExoPlayer extends BasePlayer
     audioBecomingNoisyManager =
     audioBecomingNoisyManager =
         new AudioBecomingNoisyManager(context, eventHandler, componentListener);
         new AudioBecomingNoisyManager(context, eventHandler, componentListener);
     audioFocusManager = new AudioFocusManager(context, eventHandler, componentListener);
     audioFocusManager = new AudioFocusManager(context, eventHandler, componentListener);
+    streamVolumeManager = new StreamVolumeManager(context, eventHandler, componentListener);
     wakeLockManager = new WakeLockManager(context);
     wakeLockManager = new WakeLockManager(context);
     wifiLockManager = new WifiLockManager(context);
     wifiLockManager = new WifiLockManager(context);
+    deviceInfo = createDeviceInfo(streamVolumeManager);
   }
   }
 
 
   @Override
   @Override
@@ -487,8 +496,7 @@ public class SimpleExoPlayer extends BasePlayer
   @Override
   @Override
   @Nullable
   @Nullable
   public DeviceComponent getDeviceComponent() {
   public DeviceComponent getDeviceComponent() {
-    // TODO(b/145595776): Return this after implementing DeviceComponent.
-    return null;
+    return this;
   }
   }
 
 
   /**
   /**
@@ -684,6 +692,7 @@ public class SimpleExoPlayer extends BasePlayer
               .send();
               .send();
         }
         }
       }
       }
+      streamVolumeManager.setStreamType(Util.getStreamTypeForAudioUsage(audioAttributes.usage));
       for (AudioListener audioListener : audioListeners) {
       for (AudioListener audioListener : audioListeners) {
         audioListener.onAudioAttributesChanged(audioAttributes);
         audioListener.onAudioAttributesChanged(audioAttributes);
       }
       }
@@ -1565,6 +1574,7 @@ public class SimpleExoPlayer extends BasePlayer
   public void release() {
   public void release() {
     verifyApplicationThread();
     verifyApplicationThread();
     audioBecomingNoisyManager.setEnabled(false);
     audioBecomingNoisyManager.setEnabled(false);
+    streamVolumeManager.release();
     wakeLockManager.setStayAwake(false);
     wakeLockManager.setStayAwake(false);
     wifiLockManager.setStayAwake(false);
     wifiLockManager.setStayAwake(false);
     audioFocusManager.release();
     audioFocusManager.release();
@@ -1743,6 +1753,46 @@ public class SimpleExoPlayer extends BasePlayer
     }
     }
   }
   }
 
 
+  @Override
+  public void addDeviceListener(DeviceListener listener) {
+    deviceListeners.add(listener);
+  }
+
+  @Override
+  public void removeDeviceListener(DeviceListener listener) {
+    deviceListeners.remove(listener);
+  }
+
+  @Override
+  public DeviceInfo getDeviceInfo() {
+    verifyApplicationThread();
+    return deviceInfo;
+  }
+
+  @Override
+  public int getDeviceVolume() {
+    verifyApplicationThread();
+    return streamVolumeManager.getVolume();
+  }
+
+  @Override
+  public void setDeviceVolume(int volume) {
+    verifyApplicationThread();
+    streamVolumeManager.setVolume(volume);
+  }
+
+  @Override
+  public void increaseDeviceVolume() {
+    verifyApplicationThread();
+    streamVolumeManager.increaseVolume();
+  }
+
+  @Override
+  public void decreaseDeviceVolume() {
+    verifyApplicationThread();
+    streamVolumeManager.decreaseVolume();
+  }
+
   // Internal methods.
   // Internal methods.
 
 
   private void removeSurfaceCallbacks() {
   private void removeSurfaceCallbacks() {
@@ -1898,6 +1948,13 @@ public class SimpleExoPlayer extends BasePlayer
     }
     }
   }
   }
 
 
+  private static DeviceInfo createDeviceInfo(StreamVolumeManager streamVolumeManager) {
+    return new DeviceInfo(
+        DeviceInfo.PLAYBACK_TYPE_LOCAL,
+        streamVolumeManager.getMinVolume(),
+        streamVolumeManager.getMaxVolume());
+  }
+
   private static int getPlayWhenReadyChangeReason(boolean playWhenReady, int playerCommand) {
   private static int getPlayWhenReadyChangeReason(boolean playWhenReady, int playerCommand) {
     return playWhenReady && playerCommand != AudioFocusManager.PLAYER_COMMAND_PLAY_WHEN_READY
     return playWhenReady && playerCommand != AudioFocusManager.PLAYER_COMMAND_PLAY_WHEN_READY
         ? PLAY_WHEN_READY_CHANGE_REASON_AUDIO_FOCUS_LOSS
         ? PLAY_WHEN_READY_CHANGE_REASON_AUDIO_FOCUS_LOSS
@@ -1913,6 +1970,7 @@ public class SimpleExoPlayer extends BasePlayer
           TextureView.SurfaceTextureListener,
           TextureView.SurfaceTextureListener,
           AudioFocusManager.PlayerControl,
           AudioFocusManager.PlayerControl,
           AudioBecomingNoisyManager.EventListener,
           AudioBecomingNoisyManager.EventListener,
+          StreamVolumeManager.Listener,
           Player.EventListener {
           Player.EventListener {
 
 
     // VideoRendererEventListener implementation
     // VideoRendererEventListener implementation
@@ -2145,6 +2203,26 @@ public class SimpleExoPlayer extends BasePlayer
           Player.PLAY_WHEN_READY_CHANGE_REASON_AUDIO_BECOMING_NOISY);
           Player.PLAY_WHEN_READY_CHANGE_REASON_AUDIO_BECOMING_NOISY);
     }
     }
 
 
+    // StreamVolumeManager.Listener implementation.
+
+    @Override
+    public void onStreamTypeChanged(@C.StreamType int streamType) {
+      DeviceInfo deviceInfo = createDeviceInfo(streamVolumeManager);
+      if (!deviceInfo.equals(SimpleExoPlayer.this.deviceInfo)) {
+        SimpleExoPlayer.this.deviceInfo = deviceInfo;
+        for (DeviceListener deviceListener : deviceListeners) {
+          deviceListener.onDeviceInfoChanged(deviceInfo);
+        }
+      }
+    }
+
+    @Override
+    public void onStreamVolumeChanged(int streamVolume) {
+      for (DeviceListener deviceListener : deviceListeners) {
+        deviceListener.onDeviceVolumeChanged(streamVolume);
+      }
+    }
+
     // Player.EventListener implementation.
     // Player.EventListener implementation.
 
 
     @Override
     @Override

library/core/src/main/java/com/google/android/exoplayer2/StreamVolumeManager.java

+/*
+ * Copyright 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer2;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.media.AudioManager;
+import android.os.Handler;
+import com.google.android.exoplayer2.util.Assertions;
+import com.google.android.exoplayer2.util.Util;
+
+/** A manager that wraps {@link AudioManager} to control/listen audio stream volume. */
+/* package */ final class StreamVolumeManager {
+
+  /** A listener for changes in the manager. */
+  public interface Listener {
+
+    /** Called when the audio stream type is changed. */
+    void onStreamTypeChanged(@C.StreamType int streamType);
+
+    /** Called when the audio stream volume is changed. */
+    void onStreamVolumeChanged(int streamVolume);
+  }
+
+  // TODO(b/151280453): Replace the hidden intent action with an official one.
+  // Copied from AudioManager#VOLUME_CHANGED_ACTION
+  private static final String VOLUME_CHANGED_ACTION = "android.media.VOLUME_CHANGED_ACTION";
+
+  // TODO(b/153317944): Allow users to override these flags.
+  private static final int VOLUME_FLAGS = AudioManager.FLAG_SHOW_UI;
+
+  private final Context applicationContext;
+  private final Handler eventHandler;
+  private final Listener listener;
+  private final AudioManager audioManager;
+  private final VolumeChangeReceiver receiver;
+
+  @C.StreamType private int streamType;
+  private int volume;
+
+  /** Creates a manager. */
+  public StreamVolumeManager(Context context, Handler eventHandler, Listener listener) {
+    applicationContext = context.getApplicationContext();
+    this.eventHandler = eventHandler;
+    this.listener = listener;
+    audioManager =
+        Assertions.checkStateNotNull(
+            (AudioManager) applicationContext.getSystemService(Context.AUDIO_SERVICE));
+
+    streamType = C.STREAM_TYPE_DEFAULT;
+    volume = audioManager.getStreamVolume(streamType);
+
+    receiver = new VolumeChangeReceiver();
+    IntentFilter filter = new IntentFilter(VOLUME_CHANGED_ACTION);
+    applicationContext.registerReceiver(receiver, filter);
+  }
+
+  /** Sets the audio stream type. */
+  public void setStreamType(@C.StreamType int streamType) {
+    if (this.streamType == streamType) {
+      return;
+    }
+    this.streamType = streamType;
+
+    updateVolumeAndNotifyIfChanged();
+    listener.onStreamTypeChanged(streamType);
+  }
+
+  /**
+   * Gets the minimum volume for the current audio stream. It can be changed if {@link
+   * #setStreamType(int)} is called.
+   */
+  public int getMinVolume() {
+    return Util.SDK_INT >= 28 ? audioManager.getStreamMinVolume(streamType) : 0;
+  }
+
+  /**
+   * Gets the maximum volume for the current audio stream. It can be changed if {@link
+   * #setStreamType(int)} is called.
+   */
+  public int getMaxVolume() {
+    return audioManager.getStreamMaxVolume(streamType);
+  }
+
+  /** Gets the current volume for the current audio stream. */
+  public int getVolume() {
+    return volume;
+  }
+
+  /**
+   * Sets the volume with the given value for the current audio stream. The value should be between
+   * {@link #getMinVolume()} and {@link #getMaxVolume()}, otherwise it will be ignored.
+   */
+  public void setVolume(int volume) {
+    if (volume < getMinVolume() || volume > getMaxVolume()) {
+      return;
+    }
+    audioManager.setStreamVolume(streamType, volume, VOLUME_FLAGS);
+    updateVolumeAndNotifyIfChanged();
+  }
+
+  /**
+   * Increases the volume by one for the current audio stream. It will be ignored if the current
+   * volume is equal to {@link #getMaxVolume()}.
+   */
+  public void increaseVolume() {
+    if (volume >= getMaxVolume()) {
+      return;
+    }
+    audioManager.adjustStreamVolume(streamType, AudioManager.ADJUST_RAISE, VOLUME_FLAGS);
+    updateVolumeAndNotifyIfChanged();
+  }
+
+  /**
+   * Decreases the volume by one for the current audio stream. It will be ignored if the current
+   * volume is equal to {@link #getMinVolume()}.
+   */
+  public void decreaseVolume() {
+    if (volume <= getMinVolume()) {
+      return;
+    }
+    audioManager.adjustStreamVolume(streamType, AudioManager.ADJUST_LOWER, VOLUME_FLAGS);
+    updateVolumeAndNotifyIfChanged();
+  }
+
+  /** Releases the manager. It must be called when the manager is no longer required. */
+  public void release() {
+    applicationContext.unregisterReceiver(receiver);
+  }
+
+  private void updateVolumeAndNotifyIfChanged() {
+    int newVolume = audioManager.getStreamVolume(streamType);
+    if (volume != newVolume) {
+      volume = newVolume;
+      listener.onStreamVolumeChanged(newVolume);
+    }
+  }
+
+  private final class VolumeChangeReceiver extends BroadcastReceiver {
+
+    @Override
+    public void onReceive(Context context, Intent intent) {
+      eventHandler.post(StreamVolumeManager.this::updateVolumeAndNotifyIfChanged);
+    }
+  }
+}