@class NSMutableSet, NSHashTable; @interface MPVolumeHUDController : NSObject { NSHashTable *_scenes; NSMutableSet *_displays; NSMutableSet *_categories; BOOL _needsUpdate; } @property (class, readonly, nonatomic) MPVolumeHUDController *sharedInstance; @property (readonly, nonatomic) id mainContext; - (void)setNeedsUpdate; - (id)init; - (void)addVolumeDisplay:(id)a0; - (void)_updateVisibilityForVolumeDisplays:(id)a0 inWindowScene:(id)a1; - (void)removeVolumeDisplay:(id)a0; - (void)_addCategory:(id)a0; - (void)registerView:(id)a0 inContext:(id)a1; - (void)unregisterView:(id)a0 inContext:(id)a1; - (void).cxx_destruct; - (void)_updateVisibility; @end