---
title: "tabBarController(_:sidebar:update:)"
framework: uikit
role: symbol
role_heading: Instance Method
path: "uikit/uitabbarcontroller/sidebar-swift.class/delegate-swift.protocol/tabbarcontroller(_:sidebar:update:)"
---

# tabBarController(_:sidebar:update:)

Called whenever the sidebar item’s configurationState changes or the item is reconfigured. The passed in item will accrue all modifications until the delegate requests for a new sidebar item from the delegate method tabBarController:sidebar:itemForRequest:

## Declaration

```swift
optional func tabBarController(_ tabBarController: UITabBarController, sidebar: UITabBarController.Sidebar, update item: UITabSidebarItem)
```