Liquid Glass UI

An iOS 26.4 "Liquid Glass" theme and component kit for Flutter. Drop in a frosted, translucent design system — colors, typography and ready-made widgets — and get the native-feeling glassmorphism look on any platform.

Everything is themeable through a single GlassTheme, and every component reads its blur, tint, rim-highlight and radii from that one place, so your whole app stays consistent.

Live documentation · Source code · Report an issue

• 🧊 Real BackdropFilter glass with a rim highlight and soft shadow
• 🌗 Light & dark, monochrome by default (glass + white, no blue)
• 🎞️ Smooth nav-bar animations (sliding bubble + springy pop), each toggleable
• ♿ Honors Reduce Transparency / Increase Contrast and Reduce Motion
• 📦 Tiny, dependency-free (only the Flutter SDK)

---

Install

dependencies:
  liquid_glass_ui_kit: ^0.1.0

import 'package:liquid_glass_ui_kit/liquid_glass_ui_kit.dart';

Quick start

Wrap your app (or a subtree) in a GlassTheme, then use the components:

import 'package:flutter/material.dart';
import 'package:liquid_glass_ui_kit/liquid_glass_ui_kit.dart';

class HomePage extends StatefulWidget {
  const HomePage({super.key});
  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  int _tab = 0;

  @override
  Widget build(BuildContext context) {
    return GlassTheme(
      data: GlassThemeData.dark(),
      child: GlassScaffold(
        appBar: const GlassAppBar(title: Text('Home')),
        bottomNavigationBar: GlassBottomNavBar(
          currentIndex: _tab,
          onTap: (i) => setState(() => _tab = i),
          items: const [
            GlassNavItem(icon: Icons.home_rounded, label: 'Home'),
            GlassNavItem(icon: Icons.sports_esports_rounded, label: 'Arcade'),
            GlassNavItem(icon: Icons.group_rounded, label: 'Friends'),
            GlassNavItem(icon: Icons.inventory_2_rounded, label: 'Library'),
            GlassNavItem(icon: Icons.search_rounded, label: 'Search'),
          ],
        ),
        body: ListView(
          padding: const EdgeInsets.fromLTRB(16, 120, 16, 150),
          children: [
            GlassCard(child: Text('Frosted content')),
            const SizedBox(height: 16),
            GlassButton(
              label: 'Continue',
              variant: GlassButtonVariant.filled,
              expand: true,
              onPressed: () {},
            ),
          ],
        ),
      ),
    );
  }
}

---

Components at a glance

Component	What it is	Key params
GlassSurface	The core blurred/tinted/rim-lit panel everything is built on	blurSigma, tint, highlight, borderRadius, shadow
GlassScaffold	Page shell that floats bars over a scrollable body	appBar, bottomNavigationBar, background, body
GlassAppBar	Translucent top bar (PreferredSizeWidget)	title, leading, actions, floating
GlassBottomNavBar	Floating capsule tab bar with animated indicator	items, currentIndex, onTap, animateIndicator, animateBounce, showLabels, borderRadius
GlassButton	Capsule button — glass / filled / plain	label, icon, variant, expand, onPressed
GlassCard	Padded glass panel, optionally tappable	child, padding, onTap
GlassPill	Small tag / chip / filter	label, icon, selected, onTap
GlassSwitch	iOS-style toggle with a glass track	value, onChanged
GlassSheet / showGlassBottomSheet	Bottom sheet	title, builder, heightFactor, showDragHandle
GlassDialog / showGlassDialog	Alert popup	title, message, actions
GlassActionMenu / showGlassActionMenu	Anchored context menu	items

---

The bottom nav bar & its animations

GlassBottomNavBar is the signature piece. Two animations, each independently toggleable, and both auto-disabled under Reduce Motion:

Flag	Default	Effect
animateIndicator	true	The highlight slides ("bubbles") between items. Off → it just appears on the selected item.
animateBounce	true	The selected icon and pill pop with a spring. Off → no pop.

GlassBottomNavBar(
  currentIndex: _tab,
  onTap: (i) => setState(() => _tab = i),
  items: _items,

  // Animations — turn either off on its own:
  animateIndicator: true,   // sliding bubble
  animateBounce: true,      // springy pop (icon + pill)

  // Icons-only mode:
  showLabels: false,

  // Rounding — big values clamp to a full capsule:
  borderRadius: 40,             // the bar
  indicatorBorderRadius: 32,    // the pill (defaults to concentric with the bar)
)

You supply currentIndex and rebuild on onTap — it's a controlled widget, so the selection is your state.

---

Overlays: sheet, dialog & menu

All three need a Navigator / MaterialApp ancestor (as any modal route does).

// Bottom sheet
showGlassBottomSheet(
  context: context,
  title: 'Share',
  builder: (context) => Column(mainAxisSize: MainAxisSize.min, children: [...]),
);

// Popup dialog
showGlassDialog(
  context: context,
  title: 'Delete item?',
  message: 'This action cannot be undone.',
  actions: [
    GlassDialogAction(label: 'Cancel', isDefault: true, onPressed: () => Navigator.pop(context)),
    GlassDialogAction(label: 'Delete', isDestructive: true, onPressed: () => Navigator.pop(context)),
  ],
);

// Action menu — anchored to the widget owning `context`
showGlassActionMenu(
  context: context,
  items: [
    GlassMenuItem(label: 'Edit', icon: Icons.edit_outlined),
    GlassMenuItem(label: 'Delete', icon: Icons.delete_outline, isDestructive: true),
  ],
);

For the action menu, pass the trigger widget's own context (wrap it in a Builder) so the menu anchors to it and flips above when there's no room below.

---

Buttons

GlassButton(label: 'Glass',  variant: GlassButtonVariant.glass,  onPressed: () {}),
GlassButton(label: 'Filled', variant: GlassButtonVariant.filled, onPressed: () {}),
GlassButton(label: 'Plain',  variant: GlassButtonVariant.plain,  onPressed: () {}),

// With an icon, full width, disabled:
GlassButton(
  label: 'Continue',
  icon: Icons.arrow_forward_rounded,
  variant: GlassButtonVariant.filled,
  expand: true,
  onPressed: null, // null disables it
);

• glass — frosted capsule, accent-colored label
• filled — solid accent capsule; label auto-picks black/white for contrast
• plain — text-only, no fill

The building block: GlassSurface

Compose your own frosted widgets with the same material:

GlassSurface(
  borderRadius: BorderRadius.circular(24),
  padding: const EdgeInsets.all(16),
  blurSigma: 30,           // override the theme blur
  tint: Colors.white24,    // override the tint
  child: const Text('Custom glass'),
)

---

Theming

Grab the active theme anywhere with GlassTheme.of(context):

final theme = GlassTheme.of(context);
theme.colors.accent;      // monochrome accent
theme.colors.label;       // primary text/icon color
theme.typography.title1;  // type scale
theme.metrics.blurSigma;  // shared blur strength

Customize globally by passing your own GlassThemeData:

GlassTheme(
  data: GlassThemeData.light(
    metrics: const GlassMetrics(blurSigma: 32, largeRadius: 32),
  ).copyWith(
    // Opt into a color accent if you want one:
    colors: GlassColors.light.copyWith(accent: const Color(0xFFAF52DE)),
  ),
  child: ...,
)

Palettes

The default accent is monochrome (graphite in light, near-white in dark), so out of the box it's pure glass + white with no color tint. GlassColors exposes: background, secondaryBackground, label, secondaryLabel, tertiaryLabel, accent, glassTint, glassHighlight, glassBorder, glassShadow, separator.

Follow the system light/dark mode

GlassTheme(
  data: GlassThemeData(colors: GlassColors.of(context)),
  child: ...,
)

Metrics

GlassMetrics centralizes blurSigma, borderWidth and the radii (smallRadius, mediumRadius, largeRadius, pillRadius) so you can dial the whole system up or down at once.

Fonts

The package doesn't bundle SF Pro (Apple's license forbids redistribution). On Apple platforms Flutter renders with the system font automatically, so it looks native. To match it on Android/web, bundle your own font and apply it:

final typography = GlassTypography.forColors(GlassColors.dark)
    .apply(fontFamily: 'YourSFAlike');

GlassTheme(
  data: GlassThemeData(colors: GlassColors.dark, typography: typography),
  child: ...,
)

---

Accessibility

Translucent UIs can fail WCAG contrast over busy backgrounds, so the kit honors the system settings automatically:

• Reduce Transparency / Increase Contrast → glass surfaces drop the blur and render as opaque, clearly-bordered panels.
• Reduce Motion → the press, toggle, nav, dialog and menu animations are disabled.

The default palette is monochrome and high-contrast (black/white text). Still, follow Apple's guidance: keep to roughly one glass layer per view, avoid stacking glass on glass, and verify text contrast over your real backgrounds.

The glass effect & performance

GlassSurface uses a real BackdropFilter blur, so it needs content behind it to refract — float the bars over your body (as GlassScaffold does) rather than stacking them in a plain Column. Backdrop blurs are GPU work; a handful per screen is fine, but avoid dozens of overlapping ones in long lists.

Example

The animation at the top of this page is captured from the full demo in example/. It includes every component in light and dark mode, plus live toggles for the nav-bar animations and icons-only mode.

Run it locally:

cd example
flutter run

License

MIT © 2026