android.media.AudioManager#STREAM_ACCESSIBILITY源码实例Demo

@Override
public int getIconResource() {
  switch (volumeStreamType) {
    case AudioManager.STREAM_MUSIC:
      return R.drawable.quantum_ic_music_note_white_24;
    case AudioManager.STREAM_VOICE_CALL:
      return R.drawable.quantum_ic_phone_white_24;
    case AudioManager.STREAM_RING:
      return R.drawable.quantum_ic_vibration_white_24;
    case AudioManager.STREAM_ALARM:
      return R.drawable.quantum_ic_alarm_white_24;
    case AudioManager.STREAM_ACCESSIBILITY:
      return R.drawable.quantum_ic_accessibility_new_white_24;
  }
  return 0;
}
 

@Override
public String getText() {
  switch (volumeStreamType) {
    case AudioManager.STREAM_MUSIC:
      return context.getString(R.string.volume_menu_media);
    case AudioManager.STREAM_VOICE_CALL:
      return context.getString(R.string.volume_menu_call);
    case AudioManager.STREAM_RING:
      return context.getString(R.string.volume_menu_ring);
    case AudioManager.STREAM_ALARM:
      return context.getString(R.string.volume_menu_alarm);
    case AudioManager.STREAM_ACCESSIBILITY:
      return context.getString(R.string.volume_menu_accessibility);
  }
  return "";
}
 

private static SwitchAccessMenuItemEnum.MenuItem getMenuItemEnumFromVolumeType(int volumeType) {
  switch (volumeType) {
    case AudioManager.STREAM_MUSIC:
      return SwitchAccessMenuItemEnum.MenuItem.VOLUME_SUBMENU_MEDIA;
    case AudioManager.STREAM_VOICE_CALL:
      return SwitchAccessMenuItemEnum.MenuItem.VOLUME_SUBMENU_CALL;
    case AudioManager.STREAM_RING:
      return SwitchAccessMenuItemEnum.MenuItem.VOLUME_SUBMENU_RING;
    case AudioManager.STREAM_ALARM:
      return SwitchAccessMenuItemEnum.MenuItem.VOLUME_SUBMENU_ALARM;
    case AudioManager.STREAM_ACCESSIBILITY:
      return SwitchAccessMenuItemEnum.MenuItem.VOLUME_SUBMENU_ACCESSIBILITY;
  }
  return SwitchAccessMenuItemEnum.MenuItem.ITEM_UNSPECIFIED;
}
 

private boolean canStreamBeMuted() {
  // TODO: Instead of hiding the mute button for alarm and accessibility, investigate
  // a more elegant way of determining is a volume stream can be muted and/or manually setting
  // the volume to 0 instead of using ADJUST_STREAM_MUTE. There's a bug in AudioManager that
  // causes some volume types on certain versions to not be muteable. Alarm and accessibility
  // volume are generally not considered "muteable" volume types, so manually hiding the mute
  // button for these streams doesn't significantly impact user experience.
  boolean isValidStreamType =
      (volumeStreamType != AudioManager.STREAM_ALARM)
          && (volumeStreamType != AudioManager.STREAM_ACCESSIBILITY);
  return isValidStreamType
      && ((audioManager != null) && (audioManager.getStreamMinVolume(volumeStreamType) == 0));
}
 

/**
 * Called after volume changes. Handles acquiring control of the current stream and providing
 * feedback.
 *
 * @param streamType The stream type constant.
 * @param volume The current volume.
 * @param prevVolume The previous volume.
 */
private void internalOnVolumeChanged(int streamType, int volume, int prevVolume) {
  if (isSelfAdjusted(streamType, volume)) {
    // Ignore self-adjustments.
    return;
  }

  if (FeatureSupport.hasAcessibilityAudioStream(context)
      && streamType == AudioManager.STREAM_ACCESSIBILITY) {
    cacheAccessibilityStreamVolume();
  }

  if (currentStream < 0) {
    // If the current stream hasn't been set, acquire control.
    currentStream = streamType;
    AudioManagerCompatUtils.forceVolumeControlStream(audioManager, currentStream);
    handler.onControlAcquired(streamType);
    return;
  }

  if (volume == prevVolume) {
    // Ignore ADJUST_SAME if we've already acquired control.
    return;
  }

  handler.releaseControlDelayed();
}