SwiftUI Liquid Glass

Overview

Liquid Glass is the system material introduced with the 26 releases of Apple's platforms. It belongs to the functional layer of an interface: bars, sheets, menus and controls that float above content, blur what is behind them and react to touch. An app built with the Xcode 26 SDK gets it on every standard component without code changes, so most of the work in adopting it is removing custom backgrounds that now clash, and adding glass by hand only to the few custom controls that live in that floating layer. This skill gives the decision of where glass belongs, the exact APIs, the fallback for older systems, and a review format.

Instructions

1. Establish the facts of the project

Before proposing code, find out:

• Deployment targets. grep -rnE "IPHONEOS_DEPLOYMENT_TARGET|MACOSX_DEPLOYMENT_TARGET" --include=project.pbxproj . or the platforms: list in Package.swift. Anything below 26 means every glass API needs an availability check.
• Platforms. glassEffect(_:in:) and the glass button styles exist on iOS, iPadOS, Mac Catalyst, macOS, tvOS and watchOS 26.0+. They are not available on visionOS, which has its own glassBackgroundEffect(displayMode:).
• Compatibility switch. Search the Info.plist for UIDesignRequiresCompatibility. When it is YES the app keeps its pre-26 look and none of this shows. Apple documents the key as temporary, and it is ignored once the app is built for the 27 releases.
• Existing customisation of bars and sheets: toolbarBackground, UINavigationBarAppearance, custom backgrounds behind tab bars, visual-effect views inside sheets and popovers.

2. Decide where glass goes