how to implement whole new iOS 26 liquid glass tabbar in swift uikit

To implement the new iOS 26 Liquid Glass tab bar in a UIKit app, you can follow the guidance provided in the session "Build a UIKit app with the new design" from WWDC 2025. Here are the steps you can take:

1. Recompile with Xcode 26: Start by building your app with Xcode 26. This will automatically apply the new Liquid Glass design to standard UIKit components, including the tab bar.

2. Adopt the New Design: The new design system introduces Liquid Glass, which is a dynamic and translucent material. It is applied to various UI components, including tab bars, to give them a floating appearance above the content.

3. Use UI Components: Utilize standard UIKit components like UITabBarController and UITabBar to automatically get the new Liquid Glass appearance. If you have custom controls, consider whether standard UIKit controls might be a better fit to take full advantage of the new design.

4. Customize with New APIs: If needed, use the new APIs provided to further customize the appearance and behavior of your tab bar. This includes setting up constraints and using the new UIBackgroundExtensionView to ensure your content flows seamlessly under the Liquid Glass elements.

For a detailed walkthrough, you can refer to the session Build a UIKit app with the new design (01:55) which covers how Tab Views and Split Views adopt the new design system and float above the content.