island_bottom_nav 0.2.1

iOS island-style floating bottom navigation bar for Flutter, with a composable app shell and right-aligned island FAB.

Island Bottom Nav

Configurable iOS island-style bottom navigation for Flutter.

This package provides:

• IslandBottomNavBar: floating rounded bottom nav with icon + label destinations.
• IslandFab: island-style floating action button.
• IslandAppShell: composable shell that places nav and FAB together, with FAB on the right.

Installation

dart pub add island_bottom_nav

Quick Start

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

class HomeShell extends StatefulWidget {
	const HomeShell({super.key});

	@override
	State<HomeShell> createState() => _HomeShellState();
}

class _HomeShellState extends State<HomeShell> {
	int currentIndex = 0;

	static const items = [
		IslandNavItem(
			icon: Icon(Icons.today_outlined),
			activeIcon: Icon(Icons.today),
			label: 'Today',
		),
		IslandNavItem(
			icon: Icon(Icons.newspaper_outlined),
			activeIcon: Icon(Icons.newspaper),
			label: 'News+',
		),
		IslandNavItem(
			icon: Icon(Icons.sports_football_outlined),
			activeIcon: Icon(Icons.sports_football),
			label: 'Sports',
		),
		IslandNavItem(
			icon: Icon(Icons.headset_outlined),
			activeIcon: Icon(Icons.headset),
			label: 'Audio',
		),
	];

	@override
	Widget build(BuildContext context) {
		return IslandAppShell(
			body: Center(child: Text('Selected: ${items[currentIndex].label}')),
			items: items,
			currentIndex: currentIndex,
			onDestinationSelected: (index) => setState(() => currentIndex = index),
			onFabPressed: () {
				// Search, open modal, or route to another page.
			},
		);
	}
}

Building Blocks

IslandAppShell

High-level shell with nav + right-side FAB. All visual and layout properties are controlled via a single theme: IslandNavThemeData(...) parameter.

IslandAppShell(
  theme: IslandNavThemeData(
    backgroundColor: Colors.black.withValues(alpha: 0.85),
    borderColor: Colors.transparent,
    selectedColor: Colors.teal,
    navBarHeight: 64,
    fabSpacing: 10,
    horizontalPadding: 20,
    bottomPadding: 12,
    maxIslandWidth: 540,
  ),
  body: child,
  items: items,
  currentIndex: index,
  onDestinationSelected: (i) => setState(() => index = i),
)

When theme is omitted (or individual fields are null), values are derived automatically from the ambient ColorScheme via IslandNavThemeData.defaults.

Other shell options:

• fab: provide your own custom island FAB widget.
• onFabPressed: callback used by the default IslandFab.
• extendBody: whether the body renders behind the floating bar (default: true).

IslandNavThemeData

All appearance and layout settings in one place. Every field is nullable — supply only the values you want to override.

Property	Default	Description
backgroundColor	surface @ 84 %	Capsule fill
borderColor	outline @ 45 %	Use Colors.transparent to hide
selectedColor	primary	Active icon + label
unselectedColor	onSurface @ 55 %	Inactive icon + label
labelStyle / selectedLabelStyle	12 sp	Label text styles
labelBehavior	alwaysShow	When to show labels (alwaysShow, alwaysHide, onlyShowSelected)
elevation	8	Capsule shadow
borderRadius	36	Capsule corner radius
navBarHeight	64	Bar height
fabSpacing	12	Gap between bar and FAB
bottomPadding	12	Space above system insets
horizontalPadding	16	Left/right padding of the control row
maxIslandWidth	540	Max width of the nav+FAB row

IslandBottomNavBar

Standalone floating nav when you already have your own page shell.

Key options:

• backgroundColor, borderColor, selectedColor, unselectedColor
• height, borderRadius, padding, elevation
• labelStyle, selectedLabelStyle
• labelBehavior

IslandFab

Standalone island action button.

Key options:

• icon or child
• size
• backgroundColor, foregroundColor, borderColor
• tooltip, elevation

Docs

• doc/island_app_shell.md contains detailed behavior and configuration notes.

Run The Example App

cd example
flutter pub get
flutter run

Running Tests

flutter test