Manages the volume of an audio group. Before calling any API in **AudioVolumeGroupManager**, you must use [getVolumeGroupManager](#getvolumegroupmanager9) to obtain an **AudioVolumeGroupManager** instance.
Manages the volume of an audio group. Before calling any API in **AudioVolumeGroupManager**, you must use [getVolumeGroupManager](#getvolumegroupmanager9) to obtain an **AudioVolumeGroupManager** instance.