Java source vs. Android SDK differences?

If I look at the source code for AudioManager, there is:

@SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
public static final String VOLUME_CHANGED_ACTION = "android.media.VOLUME_CHANGED_ACTION";

However, is not visible by Eclipse, even when you specify the minimum SDK level.

How can this happen?

Is 开发者_如何学Gothis part of the API or not?

Thanks

You missed the part above, the @hide indicating it is not included in the SDK:

/**
 * @hide Broadcast intent when the volume for a particular stream type changes.
 * Includes the stream, the new volume and previous volumes
 *
 * @see #EXTRA_VOLUME_STREAM_TYPE
 * @see #EXTRA_VOLUME_STREAM_VALUE
 * @see #EXTRA_PREV_VOLUME_STREAM_VALUE
 */