public static void Unregister(PurchaseObserver observer) { sPurchaseObserver = null; }
public static void Register(PurchaseObserver observer) { sPurchaseObserver = observer; }
public static void Unregister(PurchaseObserver observer) { sPurchaseObserver = null; }
public static void Register(PurchaseObserver observer) { sPurchaseObserver = observer; }