animated_bottom_navigation_bar 0.2.1

Animated Bottom Navigation Bar Widget implementation inspired by https://dribbble.com/shots/7134849-Simple-Tab-Bar-Animation

example/lib/main.dart

import 'dart:async';

import 'package:animated_bottom_navigation_bar/animated_bottom_navigation_bar.dart';
import 'package:auto_size_text/auto_size_text.dart';
import 'package:circular_reveal_animation/circular_reveal_animation.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        scaffoldBackgroundColor: Colors.white,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Animated Navigation Bottom Bar'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> with SingleTickerProviderStateMixin {
  final autoSizeGroup = AutoSizeGroup();
  var _bottomNavIndex = 0; //default index of first screen

  AnimationController _animationController;
  Animation<double> animation;
  CurvedAnimation curve;

  final iconList = <IconData>[
    Icons.brightness_5,
    Icons.brightness_4,
    Icons.brightness_6,
    Icons.brightness_7,
  ];

  @override
  void initState() {
    super.initState();
    final systemTheme = SystemUiOverlayStyle.light.copyWith(
      systemNavigationBarColor: HexColor('#373A36'),
      systemNavigationBarIconBrightness: Brightness.light,
    );
    SystemChrome.setSystemUIOverlayStyle(systemTheme);

    _animationController = AnimationController(
      duration: Duration(seconds: 1),
      vsync: this,
    );
    curve = CurvedAnimation(
      parent: _animationController,
      curve: Interval(
        0.5,
        1.0,
        curve: Curves.fastOutSlowIn,
      ),
    );
    animation = Tween<double>(
      begin: 0,
      end: 1,
    ).animate(curve);

    Future.delayed(
      Duration(seconds: 1),
      () => _animationController.forward(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      extendBody: true,
      appBar: AppBar(
        title: Text(
          widget.title,
          style: TextStyle(color: Colors.white),
        ),
        backgroundColor: HexColor('#373A36'),
      ),
      body: NavigationScreen(
        iconList[_bottomNavIndex],
      ),
      floatingActionButton: ScaleTransition(
        scale: animation,
        child: FloatingActionButton(
          elevation: 8,
          backgroundColor: HexColor('#FFA400'),
          child: Icon(
            Icons.brightness_3,
            color: HexColor('#373A36'),
          ),
          onPressed: () {
            _animationController.reset();
            _animationController.forward();
          },
        ),
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
      bottomNavigationBar: AnimatedBottomNavigationBar.builder(
        itemCount: iconList.length,
        tabBuilder: (int index, bool isActive) {
          final color = isActive ? HexColor('#FFA400') : Colors.white;
          return Column(
            mainAxisSize: MainAxisSize.min,
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Icon(
                iconList[index],
                size: 24,
                color: color,
              ),
              const SizedBox(height: 4),
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 8),
                child: AutoSizeText(
                  "brightness $index",
                  maxLines: 1,
                  style: TextStyle(color: color),
                  group: autoSizeGroup,
                ),
              )
            ],
          );
        },
        backgroundColor: HexColor('#373A36'),
        activeIndex: _bottomNavIndex,
        splashColor: HexColor('#FFA400'),
        notchAndCornersAnimation: animation,
        splashSpeedInMilliseconds: 300,
        notchSmoothness: NotchSmoothness.defaultEdge,
        gapLocation: GapLocation.center,
        leftCornerRadius: 32,
        rightCornerRadius: 32,
        onTap: (index) => setState(() => _bottomNavIndex = index),
      ),
    );
  }
}

class NavigationScreen extends StatefulWidget {
  final IconData iconData;

  NavigationScreen(this.iconData) : super();

  @override
  _NavigationScreenState createState() => _NavigationScreenState();
}

class _NavigationScreenState extends State<NavigationScreen> with TickerProviderStateMixin {
  AnimationController _controller;
  Animation<double> animation;

  @override
  void didUpdateWidget(NavigationScreen oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.iconData != widget.iconData) {
      _startAnimation();
    }
  }

  @override
  void initState() {
    _controller = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 1000),
    );
    animation = CurvedAnimation(
      parent: _controller,
      curve: Curves.easeIn,
    );
    _controller.forward();
    super.initState();
  }

  _startAnimation() {
    _controller = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 1000),
    );
    animation = CurvedAnimation(
      parent: _controller,
      curve: Curves.easeIn,
    );
    _controller.forward();
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      width: double.infinity,
      height: double.infinity,
      color: Colors.white,
      child: Center(
        child: CircularRevealAnimation(
          animation: animation,
          centerOffset: Offset(80, 80),
          maxRadius: MediaQuery.of(context).size.longestSide * 1.1,
          child: Icon(
            widget.iconData,
            color: HexColor('#FFA400'),
            size: 160,
          ),
        ),
      ),
    );
  }
}

class HexColor extends Color {
  HexColor(final String hexColor) : super(_getColorFromHex(hexColor));

  static int _getColorFromHex(String hexColor) {
    hexColor = hexColor.toUpperCase().replaceAll('#', '');
    if (hexColor.length == 6) {
      hexColor = 'FF' + hexColor;
    }
    return int.parse(hexColor, radix: 16);
  }
}