Fixing inventory item handling

src/me/yaruma/fightsystem/listener/InventoryListener.java

@@ -2,6 +2,7 @@ package me.yaruma.fightsystem.listener;
 
 import me.yaruma.fightsystem.FightSystem;
 import me.yaruma.fightsystem.fight.FightState;
+import org.bukkit.Material;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.inventory.InventoryClickEvent;
@@ -26,14 +27,15 @@ public class InventoryListener implements Listener {
                 if (clickedOn != null && event.getView().getTopInventory().getType() != InventoryType.CRAFTING && clicked == event.getWhoClicked().getInventory()) {
                     event.setCancelled(true);
                 }
-        }else if (clicked != event.getWhoClicked().getInventory()) {
-            ItemStack onCursor = event.getCurrentItem();
-
-            if (onCursor != null && event.getClickedInventory().getType() != InventoryType.PLAYER){
+        }else if (
+                clicked != event.getWhoClicked().getInventory() &&
+                clicked != null &&
+                clicked.getType() != InventoryType.PLAYER &&
+                event.getCursor() != null &&
+                event.getCursor().getType() != Material.AIR){
             event.setCancelled(true);
         }
     }
-    }
 
     @EventHandler
     public void onInventoryDrag(InventoryDragEvent event) {