Similar to vanilla call Entity#onEquipItem when a player sets an item in an armor slot or the offhand slot. This makes putting items in the armor slots play the equip sound

Author: pupnewfster

src/main/java/mekanism/common/inventory/container/MekanismContainer.java

@@ -231,7 +231,7 @@ protected void addArmorSlots(@NotNull Inventory inv, int x, int y, int offhandOf
             y += 18;
         }
         if (offhandOffset != -1) {
-            addSlot(new OffhandSlot(inv, 40, x, y + offhandOffset));
+            addSlot(new OffhandSlot(inv, 40, x, y + offhandOffset, inv.player));
         }
     }
 

src/main/java/mekanism/common/inventory/container/ModuleTweakerContainer.java

@@ -49,7 +49,7 @@ public boolean mayPlace(@NotNull ItemStack stack) {
                 }
             });
         }
-        addSlot(new OffhandSlot(inv, 40, 8, 16 + 18 * 4) {
+        addSlot(new OffhandSlot(inv, 40, 8, 16 + 18 * 4, inv.player) {
             @Override
             public boolean mayPickup(@NotNull Player player) {
                 return false;

src/main/java/mekanism/common/inventory/container/slot/ArmorSlot.java

@@ -16,13 +16,21 @@ public class ArmorSlot extends InsertableSlot {
                                                                      InventoryMenu.EMPTY_ARMOR_SLOT_CHESTPLATE, InventoryMenu.EMPTY_ARMOR_SLOT_HELMET};
 
     private final EquipmentSlot slotType;
+    private final Player owner;
 
     public ArmorSlot(Inventory inventory, int index, int x, int y, EquipmentSlot slotType) {
         super(inventory, index, x, y);
         this.slotType = slotType;
+        this.owner = inventory.player;
         setBackground(InventoryMenu.BLOCK_ATLAS, ARMOR_SLOT_TEXTURES[this.slotType.getIndex()]);
     }
 
+    @Override
+    public void setByPlayer(@NotNull ItemStack newStack, @NotNull ItemStack oldStack) {
+        this.owner.onEquipItem(slotType, oldStack, newStack);
+        super.setByPlayer(newStack, oldStack);
+    }
+
     @Override
     public int getMaxStackSize() {
         return 1;

src/main/java/mekanism/common/inventory/container/slot/OffhandSlot.java

@@ -1,12 +1,25 @@
 package mekanism.common.inventory.container.slot;
 
 import net.minecraft.world.Container;
+import net.minecraft.world.entity.EquipmentSlot;
+import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.inventory.InventoryMenu;
+import net.minecraft.world.item.ItemStack;
+import org.jetbrains.annotations.NotNull;
 
 public class OffhandSlot extends InsertableSlot {
 
-    public OffhandSlot(Container inventory, int index, int x, int y) {
+    private final Player owner;
+
+    public OffhandSlot(Container inventory, int index, int x, int y, Player owner) {
         super(inventory, index, x, y);
+        this.owner = owner;
         setBackground(InventoryMenu.BLOCK_ATLAS, InventoryMenu.EMPTY_ARMOR_SLOT_SHIELD);
     }
+
+    @Override
+    public void setByPlayer(@NotNull ItemStack newStack, @NotNull ItemStack oldStack) {
+        this.owner.onEquipItem(EquipmentSlot.OFFHAND, oldStack, newStack);
+        super.setByPlayer(newStack, oldStack);
+    }
 }