Swiftui Liquid Glass

SwiftUI Liquid Glass

Overview

Liquid Glass is a dynamic material in iOS 26+ that combines optical glass properties with fluidity. It blurs content, reflects surrounding color and light, and reacts to touch interactions in real time.

Workflow Decision Tree

1) Review an existing feature

• Inspect where Liquid Glass should/shouldn't be used
• Verify correct modifier order, shape usage, container placement
• Check for iOS 26+ availability handling and fallbacks

2) Improve a feature using Liquid Glass

• Identify target components (surfaces, chips, buttons, cards)
• Refactor to use GlassEffectContainer for multiple glass elements
• Add interactive glass only for tappable/focusable elements

3) Implement a new feature using Liquid Glass

• Design glass surfaces and interactions first (shape, prominence, grouping)
• Add glass modifiers after layout/appearance modifiers
• Add morphing transitions only when view hierarchy changes with animation

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
• Gate with #available(iOS 26, *) and provide non-glass fallback

Review Checklist

• Availability: #available(iOS 26, *) present with fallback UI
• 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
• Consistency: Shapes, tinting, and spacing align across feature

Implementation Checklist

• Define target elements and desired glass prominence
• Wrap grouped glass elements in GlassEffectContainer with spacing
• Use .glassEffect(.regular.tint(...).interactive(), in: .rect(cornerRadius: ...)) as needed
• Use .buttonStyle(.glass) / .buttonStyle(.glassProminent) for actions
• Add morphing transitions with glassEffectID when hierarchy changes
• Provide fallback materials for earlier iOS versions

Quick Snippets

Basic Glass Effect 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))
}

Multiple Glass 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)

Morphing Transitions

@State private var isExpanded = false
@Namespace private var namespace

GlassEffectContainer(spacing: 40) {
    HStack(spacing: 40) {
        Image(systemName: "pencil")
            .frame(width: 80, height: 80)
            .glassEffect()
            .glassEffectID("pencil", in: namespace)

        if isExpanded {
            Image(systemName: "eraser")
                .frame(width: 80, height: 80)
                .glassEffect()
                .glassEffectID("eraser", in: namespace)
        }
    }
}

Button("Toggle") {
    withAnimation {
        isExpanded.toggle()
    }
}
.buttonStyle(.glass)

Customizing Glass

Text("Tinted Glass")
    .padding()
    .glassEffect(.regular.tint(.orange).interactive(), in: .capsule)

Uniting Glass Effects

@Namespace private var namespace

GlassEffectContainer(spacing: 20) {
    HStack(spacing: 20) {
        ForEach(items.indices, id: \.self) { index in
            ItemView(item: items[index])
                .glassEffect()
                .glassEffectUnion(id: index < 2 ? "group1" : "group2", namespace: namespace)
        }
    }
}

Shape Options

• .capsule (default)
• .rect(cornerRadius: CGFloat)
• .circle

Fallback Materials

When gating with #available(iOS 26, *), fall back to a Material, ordered from closest to glass appearance to most opaque:

• .ultraThinMaterial -- closest to glass appearance
• .thinMaterial -- slightly more opaque
• .regularMaterial -- standard blur
• .thickMaterial -- more opaque
• .ultraThickMaterial -- most opaque

System Design Notes

• Toolbar icons render monochrome by default in the new design. The monochrome palette reduces visual noise and maintains legibility -- use tint(_:) only to convey meaning (e.g. a call to action), not for visual effect.
• Partial-height sheets use a Liquid Glass background by default. If a custom presentationBackground(_:) was previously applied, consider removing it to let the new material shine. Sheets can morph out of the glass controls that present them using navigationZoomTransition.
• Scroll edge effects automatically blur and fade content under system toolbars to keep controls legible. Remove any custom background-darkening effects behind bar items -- they interfere with the automatic effect.

Source: "Build a SwiftUI app with the new design" (WWDC25, session 323)

Best Practices

1. Container Usage: Always use GlassEffectContainer for multiple glass views
2. Modifier Order: Apply .glassEffect() after appearance modifiers
3. Spacing: Choose spacing values carefully to control effect merging
4. Animation: Use animations when changing view hierarchies for smooth morphing
5. Interactivity: Add .interactive() only to touchable elements
6. Consistency: Maintain consistent shapes and styles across your app

Source: split from AvdLee/SwiftUI-Agent-Skill's reference material; also cites Apple's WWDC25 session 323 for one design note.