Update

Assets/Script/PlayerController.cs

@@ -7,6 +7,12 @@ public class PlayerController : MonoBehaviour
 
     void Update()
     {
+        if (joystick == null)
+        {
+            Debug.LogWarning("Joystick is not assigned in PlayerController!");
+            return;
+        }
+
         // Lấy input từ Joystick
         float horizontal = joystick.Horizontal;
         float vertical = joystick.Vertical;