Hello i am making a game with a shop and i have a button that should sell a item but when i click it i get this error message:
NullReferenceException: Object reference not set to an instance of an object
ShopItem.Sell () (at Assets/Scripts/ShopItem.cs:48)
UnityEngine.Events.InvokableCall.Invoke () (at :0)
UnityEngine.Events.UnityEvent.Invoke () (at :0)
UnityEngine.UI.Button.Press () (at D:/Unity Editors/2019.4.12f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/UI/Core/Button.cs:68)
UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at D:/Unity Editors/2019.4.12f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/UI/Core/Button.cs:110)
UnityEngine.EventSystems.ExecuteEvents.Execute (UnityEngine.EventSystems.IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at D:/Unity Editors/2019.4.12f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/EventSystem/ExecuteEvents.cs:50)
UnityEngine.EventSystems.ExecuteEvents.Execute[T] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.ExecuteEvents+EventFunction`1[T1] functor) (at D:/Unity Editors/2019.4.12f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/EventSystem/ExecuteEvents.cs:261)
UnityEngine.EventSystems.EventSystem:Update() (at D:/Unity Editors/2019.4.12f1/Editor/Data/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/EventSystem/EventSystem.cs:377)
Here is the code for the button:
public void Sell()
{
int currentSilver = PlayerManager.instance.GetComponent().silver;
int currentGold = PlayerManager.instance.GetComponent().gold;
Debug.Log("Trying to sell " + item);
if (Inventory.instance.items.Contains(item))
{
currentSilver = currentSilver + item.buyValueSilver;
currentGold = currentGold + item.buyValueGold;
Inventory.instance.Remove(item);
Debug.Log("Sold " + item);
}
}
Please help me i am new to Unity 