Liquid Glass & new SwiftUI (iOS 26 · 27)

How it works — Liquid Glass (iOS 26)

• .glassEffect(_:in:) — default .regular in a capsule behind the view’s bounds. .regular = adaptive, use almost always · .clear = only over media, with a dimming layer · .identity = off, same layout. .tint(_:), .interactive() (bounce/shimmer on touch).
• GlassEffectContainer(spacing:) renders its glass together; shapes nearer than spacing blend. Morph: glassEffectID(_:in:) + @Namespace + state change in withAnimation; glassEffectUnion(id: namespace:) joins views; glassEffectTransition(.matchedGeometry) or .materialize.
• .buttonStyle(.glass) / .glassProminent (primary action).
• .tabBarMinimizeBehavior(.onScrollDown) (iPhone) · .tabViewBottomAccessory{} (inline when minimised: read tabViewBottomAccessoryPlacement) · Tab(role: .search) + .searchable: the field replaces the bar.
• Toolbars share glass: ToolbarSpacer(.fixed | .flexible), .sharedBackgroundVisibility(.hidden), .badge(n); .scrollEdgeEffectStyle(.hard, for: .top).
• .backgroundExtensionEffect(): mirrors + blurs a view into the safe area (hero image under a sidebar). Once per screen.
• UIKit: UIGlassEffect, UIButton.Configuration.glass(). Opt-out UIDesignRequiresCompatibility: honoured with the 26 SDK, ignored when building for 27.

Design + accessibility

• Glass = navigation layer only; never glass on glass (fills/vibrancy on top); tint for meaning, not decoration; drop custom bar backgrounds.
• Automatic: Reduce Transparency → frostier · Increase Contrast → black/white + border · Reduce Motion → no elastic effects. Test custom glass with each.

Interview traps

• Glass on list cells, everywhere, or stacked on glass.
• Glass views without a container — no blend, no morph.
• “We’ll keep the old look” — opt-out ignored with the 27 SDK.
• @State var m = Model() + init assignment — error on 27.

Remember

“Content below, glass above, one container, one ID.”

Example

@Namespace private var ns
@State private var open = false
GlassEffectContainer(spacing: 16) {
  HStack(spacing: 16) {
    Button("Edit", systemImage: "pencil") {
      withAnimation { open.toggle() } }
      .buttonStyle(.glass).glassEffectID("edit", in: ns)
    if open {
      Image(systemName: "trash").padding()
        .glassEffect(.regular.tint(.red).interactive())
        .glassEffectID("trash", in: ns)   // morphs out
    } } }
TabView { /* Tabs */ Tab(role: .search) { SearchView() } }
  .tabBarMinimizeBehavior(.onScrollDown)
  .tabViewBottomAccessory { NowPlayingBar() }

New SwiftUI — iOS 26

• WebView(page) + WebPage (WebKit, @Observable): load returns an AsyncSequence of navigation events; callJavaScript.
• TextEditor(text: $attributed) edits an AttributedString (rich text).
• @Animatable synthesises animatableData (@AnimatableIgnored opts out); a macro, so it back-deploys. Also Chart3D, SwiftUI instrument.

New SwiftUI — iOS 27

• @State is a macro: an @Observable object is created lazily, once per view lifetime (back to iOS 17). Source break: default value and init assignment → error — drop the default (TN3211).
• @ContentBuilder unifies builders (faster type-checking) · documents: WritableDocument snapshot → DocumentWriter writes off-main.
• .reorderable() + .reorderContainer(for:) in any container · .swipeActions anywhere inside .swipeActionsContainer().
• .alert(_:item:), .confirmationDialog(_:item:) · AsyncImage obeys HTTP caching (.asyncImageURLSession).
• Tab(role: .prominent), ToolbarOverflowMenu, .visibilityPriority(.high), .toolbarMinimizeBehavior(…).

Likely questions

1. Regular vs clear? — adaptive vs transparent over media.
2. Morph two glass buttons? — container + glassEffectID + animation.
3. @State in 27? — lazy one-time init; source break.