check for menu button

SideMenuController.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name = 'SideMenuController'
-  s.version = '0.2.3'
+  s.version = '0.2.4'
   s.license = 'MIT'
   s.summary = 'Fully customisable and easy to use side menu controller written in Swift.'
   s.description = 'SideMenuController is a custom container view controller written in Swift which will display the main content within a center panel and the secondary content (option menu, navigation menu, etc.) within a side panel when triggered. The side panel can be displayed either on the left or on the right side, under or over the center panel.'

Source/UIKitExtensions.swift

@@ -48,23 +48,37 @@ public extension UINavigationController {
         button.setImage(image, for: .normal)
         button.addTarget(sideMenuController, action: #selector(SideMenuController.toggle), for: UIControlEvents.touchUpInside)
 
+        if SideMenuController.preferences.drawing.sidePanelPosition.isPositionedLeft {
+            let newItems = computeNewItems(sideMenuController: sideMenuController, button: button, controller: self.topViewController, positionLeft: true)
+            self.topViewController?.navigationItem.leftBarButtonItems = newItems
+        } else {
+            let newItems = computeNewItems(sideMenuController: sideMenuController, button: button, controller: self.topViewController, positionLeft: false)
+            self.topViewController?.navigationItem.rightBarButtonItems = newItems
+        }
+
+        completion?(button)
+    }
+
+    private func computeNewItems(sideMenuController: SideMenuController, button: UIButton, controller: UIViewController?, positionLeft: Bool) -> [UIBarButtonItem] {
+
+        var items: [UIBarButtonItem] = (positionLeft ? self.topViewController?.navigationItem.leftBarButtonItems :
+            self.topViewController?.navigationItem.rightBarButtonItems) ?? []
+
+        for item in items {
+            if let button = item.customView as? UIButton,
+                button.allTargets.contains(sideMenuController) {
+                return items
+            }
+        }
+
         let item:UIBarButtonItem = UIBarButtonItem()
         item.customView = button
 
         let spacer = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.fixedSpace, target: nil, action: nil)
         spacer.width = -10
 
-        if SideMenuController.preferences.drawing.sidePanelPosition.isPositionedLeft {
-            var items = self.topViewController?.navigationItem.leftBarButtonItems ?? []
-            items.append(contentsOf: [spacer, item])
-            self.topViewController?.navigationItem.leftBarButtonItems = items
-        } else {
-            var items = self.topViewController?.navigationItem.rightBarButtonItems ?? []
-            items.append(contentsOf: [spacer, item])
-            self.topViewController?.navigationItem.rightBarButtonItems = [spacer, item]
-        }
-
-        completion?(button)
+        items.append(contentsOf: positionLeft ? [spacer, item] : [item, spacer])
+        return items
     }
 }