Swiftui Liquid Glass

SwiftUI Liquid Glass

Overview

Use this skill to build or review SwiftUI features that fully align with the iOS 26+ Liquid Glass API. Prioritize native APIs (glassEffect, GlassEffectContainer, glass button styles) and Apple design guidance. Keep usage consistent, interactive where needed, and performance aware.

Glass API Reference

Core Modifier

func glassEffect<S: Shape>(
    _ glass: Glass = .regular,
    in shape: S = DefaultGlassEffectShape,  // capsule
    isEnabled: Bool = true
) -> some View

Glass Variants (IMPORTANT: Only 3 exist)

WARNING: There is NO .prominent variant. For prominent styling, use .buttonStyle(.glassProminent) on buttons only.

Shapes

• .capsule (default)
• .circle
• .ellipse
• .rect(cornerRadius:) — supports .containerConcentric for auto-matching parent corners
• Any custom Shape conforming type

Tinting

.glassEffect(.regular.tint(.blue))
.glassEffect(.regular.tint(.purple.opacity(0.6)))

Interactivity (iOS only)

.glassEffect(.regular.interactive())

Enables: scaling, bouncing, shimmering, touch-point illumination, gesture response.

Workflow Decision Tree

Choose the path that matches the request:

1) Review an existing feature

• Inspect where Liquid Glass should be used and where it should not.
• Verify correct modifier order, shape usage, and container placement.
• Check for iOS 26+ availability handling and sensible fallbacks.
• Verify NO .prominent variant used (only .regular, .clear, .identity).

2) Improve a feature using Liquid Glass

• Identify target components for glass treatment (surfaces, chips, buttons, cards).
• Refactor to use GlassEffectContainer where multiple glass elements appear.
• Introduce interactive glass only for tappable or focusable elements.
• Use glassEffectUnion to visually merge related controls (like Apple Maps zoom controls).

3) Implement a new feature using Liquid Glass

• Design the glass surfaces and interactions first (shape, variant, grouping).
• Add glass modifiers after layout/appearance modifiers.
• Add morphing transitions only when the view hierarchy changes with animation.
• Use tabViewBottomAccessory for persistent controls above tab bar.

Core Guidelines

• Prefer native Liquid Glass APIs over custom blurs.
• Use GlassEffectContainer when multiple glass elements coexist.
• Apply .glassEffect(...) after layout and visual modifiers.
• Use .interactive() for elements that respond to touch/pointer.
• Keep shapes consistent across related elements for a cohesive look.
• Gate with #available(iOS 26, *) and provide a non-glass fallback.
• Glass cannot sample other glass — use containers, never stack glass layers.
• Text on glass receives automatic vibrant treatment with contrast adjustment.
• Do NOT add custom shadows or borders — the system handles edge effects.

Review Checklist

• Availability: #available(iOS 26, *) present with fallback UI.
• Variants: Only .regular, .clear, .identity used (NOT .prominent).
• Composition: Multiple glass views wrapped in GlassEffectContainer.
• Modifier order: glassEffect applied after layout/appearance modifiers.
• Interactivity: interactive() only where user interaction exists.
• Transitions: glassEffectID used with @Namespace for morphing.
• Unions: Related controls grouped with glassEffectUnion.
• Consistency: Shapes, tinting, and spacing align across the feature.
• No manual shadows/borders: Trust the system edge effects.
• Accessibility: System auto-adapts for Reduce Transparency; use .identity as manual fallback.

Implementation Checklist

• Define target elements and desired glass variant (.regular for most, .clear for media overlays).
• Wrap grouped glass elements in GlassEffectContainer and tune spacing.
• Use .glassEffect(.regular.tint(...).interactive(), in: .rect(cornerRadius: ...)) as needed.
• Use .buttonStyle(.glass) / .buttonStyle(.glassProminent) for actions.
• Use glassEffectUnion(id:namespace:) to merge related controls into one glass shape.
• Add morphing transitions with glassEffectID when hierarchy changes.
• Provide fallback materials and visuals for earlier iOS versions.
• Use tabViewBottomAccessory for persistent floating controls (like Now Playing).

Quick Snippets

Basic Glass with Fallback

if #available(iOS 26, *) {
    Text("Hello")
        .padding()
        .glassEffect(.regular.interactive(), in: .rect(cornerRadius: 16))
} else {
    Text("Hello")
        .padding()
        .background(.ultraThinMaterial, in: RoundedRectangle(cornerRadius: 16))
}

Container with Multiple Elements

GlassEffectContainer(spacing: 24) {
    HStack(spacing: 24) {
        Image(systemName: "scribble.variable")
            .frame(width: 72, height: 72)
            .font(.system(size: 32))
            .glassEffect()
        Image(systemName: "eraser.fill")
            .frame(width: 72, height: 72)
            .font(.system(size: 32))
            .glassEffect()
    }
}

Glass Buttons

Button("Confirm") { }
    .buttonStyle(.glassProminent)

Button("Cancel") { }
    .buttonStyle(.glass)

Union — Merge Controls into One Glass Shape

@Namespace private var ns

GlassEffectContainer(spacing: 20) {
    HStack(spacing: 20) {
        Button("+") { }.glassEffect()
            .glassEffectUnion(id: "zoom", namespace: ns)
        Button("-") { }.glassEffect()
            .glassEffectUnion(id: "zoom", namespace: ns)
    }
}

Morphing Transition

@Namespace private var ns
@State private var expanded = false

GlassEffectContainer {
    if expanded {
        ExpandedToolbar()
            .glassEffect()
            .glassEffectID("toolbar", in: ns)
    } else {
        CompactFAB()
            .glassEffect()
            .glassEffectID("toolbar", in: ns)
    }
}
.onTapGesture {
    withAnimation(.bouncy) { expanded.toggle() }
}

Tab Bar Bottom Accessory (iOS 26)

TabView {
    HomeView().tabItem { Label("Home", systemImage: "house") }
}
.tabViewBottomAccessory {
    NowPlayingBar()  // Gets glass capsule automatically
}

Sheet Morphing from Toolbar (iOS 26)

@Namespace private var ns

.toolbar {
    ToolbarItem {
        Button("Add") { showSheet = true }
            .matchedTransitionSource(id: "add", in: ns)
    }
}
.sheet(isPresented: $showSheet) {
    AddItemView()
        .navigationTransition(.zoom(sourceID: "add", in: ns))
}

Sidebar Background Extension

NavigationSplitView {
    SidebarContent()
} detail: {
    DetailContent()
        .background {
            Image("hero").backgroundExtensionEffect()
        }
}

Scroll Extension Under Sidebar

ScrollView(.horizontal) {
    // Content extends under sidebar
}
.scrollExtensionMode(.underSidebar)

Accessibility-Aware Glass

@Environment(\.accessibilityReduceTransparency) var reduceTransparency

// iOS 26 auto-adapts: increases frosting, adds stark colors/borders
// Manual override only when needed:
.glassEffect(reduceTransparency ? .identity : .regular)

Common Mistakes

Resources

• Reference guide: references/liquid-glass.md
• Apple: Applying Liquid Glass
• WWDC25 Session 219: Meet Liquid Glass
• WWDC25 Session 323: Build a SwiftUI app with the new design
• LiquidGlassReference (Community)
• Donny Wals: Designing custom UI with Liquid Glass