1 files changed, 108 insertions, 0 deletions
diff --git a/src/com/android/tv/AudioManagerHelper.java b/src/com/android/tv/AudioManagerHelper.java
new file mode 100644
index 00000000..4fca06ac
--- /dev/null
+++ b/src/com/android/tv/AudioManagerHelper.java
@@ -0,0 +1,108 @@
+package com.android.tv;
+
+import android.app.Activity;
+import android.content.Context;
+import android.media.AudioManager;
+import android.os.Build;
+
+import com.android.tv.receiver.AudioCapabilitiesReceiver;
+import com.android.tv.ui.TunableTvView;
+
+/**
+ * A helper class to help {@link MainActivity} to handle audio-related stuffs.
+ */
+class AudioManagerHelper implements AudioManager.OnAudioFocusChangeListener {
+    private static final float AUDIO_MAX_VOLUME = 1.0f;
+    private static final float AUDIO_MIN_VOLUME = 0.0f;
+    private static final float AUDIO_DUCKING_VOLUME = 0.3f;
+
+    private final Activity mActivity;
+    private final TunableTvView mTvView;
+    private final AudioManager mAudioManager;
+    private final AudioCapabilitiesReceiver mAudioCapabilitiesReceiver;
+
+    private boolean mAc3PassthroughSupported;
+    private int mAudioFocusStatus = AudioManager.AUDIOFOCUS_LOSS;
+
+    AudioManagerHelper(Activity activity, TunableTvView tvView) {
+        mActivity = activity;
+        mTvView = tvView;
+        mAudioManager = (AudioManager) activity.getSystemService(Context.AUDIO_SERVICE);
+        mAudioCapabilitiesReceiver = new AudioCapabilitiesReceiver(activity,
+                new AudioCapabilitiesReceiver.OnAc3PassthroughCapabilityChangeListener() {
+                    @Override
+                    public void onAc3PassthroughCapabilityChange(boolean capability) {
+                        mAc3PassthroughSupported = capability;
+                    }
+                });
+        mAudioCapabilitiesReceiver.register();
+    }
+
+    /**
+     * Sets suitable volume to {@link TunableTvView} according to the current audio focus.
+     * If the focus status is {@link AudioManager#AUDIOFOCUS_LOSS} and the activity is under PIP
+     * mode, this method will finish the activity.
+     */
+    void setVolumeByAudioFocusStatus() {
+        if (mTvView.isPlaying()) {
+            switch (mAudioFocusStatus) {
+                case AudioManager.AUDIOFOCUS_GAIN:
+                    mTvView.setStreamVolume(AUDIO_MAX_VOLUME);
+                    break;
+                case AudioManager.AUDIOFOCUS_LOSS:
+                    if (Features.PICTURE_IN_PICTURE.isEnabled(mActivity)
+                            && Build.VERSION.SDK_INT >= Build.VERSION_CODES.N
+                            && mActivity.isInPictureInPictureMode()) {
+                        mActivity.finish();
+                        break;
+                    }
+                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
+                    mTvView.setStreamVolume(AUDIO_MIN_VOLUME);
+                    break;
+                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
+                    mTvView.setStreamVolume(AUDIO_DUCKING_VOLUME);
+                    break;
+            }
+        }
+    }
+
+    /**
+     * Tries to request audio focus from {@link AudioManager} and set volume according to the
+     * returned result.
+     */
+    void requestAudioFocus() {
+        int result = mAudioManager.requestAudioFocus(this,
+                AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);
+        mAudioFocusStatus = (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) ?
+                AudioManager.AUDIOFOCUS_GAIN : AudioManager.AUDIOFOCUS_LOSS;
+        setVolumeByAudioFocusStatus();
+    }
+
+    /**
+     * Abandons audio focus.
+     */
+    void abandonAudioFocus() {
+        mAudioFocusStatus = AudioManager.AUDIOFOCUS_LOSS;
+        mAudioManager.abandonAudioFocus(this);
+    }
+
+    /**
+     * Returns {@code true} if the device supports AC3 pass-through.
+     */
+    boolean isAc3PassthroughSupported() {
+        return mAc3PassthroughSupported;
+    }
+
+    /**
+     * Release the resources the helper class may occupied.
+     */
+    void release() {
+        mAudioCapabilitiesReceiver.unregister();
+    }
+
+    @Override
+    public void onAudioFocusChange(int focusChange) {
+        mAudioFocusStatus = focusChange;
+        setVolumeByAudioFocusStatus();
+    }
+}