rolling_nav_bar 0.0.4

A Flutter nav bar with a rolling active indicator behind each icon

example/lib/main.dart

import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:polygon_clipper/polygon_clipper.dart';
import 'package:rolling_nav_bar/indexed.dart';
import 'package:rolling_nav_bar/rolling_nav_bar.dart';

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

double scaledHeight(BuildContext context, double baseSize) {
  return baseSize * (MediaQuery.of(context).size.height / 800);
}

double scaledWidth(BuildContext context, double baseSize) {
  return baseSize * (MediaQuery.of(context).size.width / 375);
}

class MyApp extends StatefulWidget {
  // This widget is the root of your application.
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  Color logoColor;
  int activeIndex;

  var iconData = <IconData>[
    Icons.home,
    Icons.people,
    Icons.account_circle,
    Icons.chat,
    Icons.settings,
  ];

  var badges = <int>[null, null, null, null, null];

  var iconText = <Widget>[
    Text('Home', style: TextStyle(color: Colors.grey, fontSize: 12)),
    Text('Friends', style: TextStyle(color: Colors.grey, fontSize: 12)),
    Text('Account', style: TextStyle(color: Colors.grey, fontSize: 12)),
    Text('Chat', style: TextStyle(color: Colors.grey, fontSize: 12)),
    Text('Settings', style: TextStyle(color: Colors.grey, fontSize: 12)),
  ];

  var indicatorColors = <Color>[
    Colors.red,
    Colors.orange,
    Colors.green,
    Colors.blue,
    Colors.purple,
  ];

  List<Widget> get badgeWidgets => indexed(badges)
      .map((Indexed indexed) => indexed.value != null
          ? Text(indexed.value.toString(),
              style: TextStyle(
                color: indexed.index == activeIndex
                    ? indicatorColors[indexed.index]
                    : Colors.white,
              ))
          : null)
      .toList();

  @override
  void initState() {
    logoColor = Colors.red[600];
    activeIndex = 0;
    super.initState();
  }

  void incrementIndex() {
    setState(() {
      activeIndex = activeIndex < (iconData.length - 1) ? activeIndex + 1 : 0;
    });
  }

  _onAnimate(AnimationUpdate update) {
    setState(() {
      logoColor = update.color;
    });
  }

  _onTap(int index) {
    if (activeIndex == index) {
      _incrementBadge();
    }
    activeIndex = index;
    setState(() {});
  }

  void _incrementBadge() {
    badges[activeIndex] =
        badges[activeIndex] == null ? 1 : badges[activeIndex] + 1;
    setState(() {});
  }

  List<Widget> get builderChildren => const <Widget>[
        Text('1', style: TextStyle(color: Colors.grey)),
        Text('2', style: TextStyle(color: Colors.grey)),
        Text('3', style: TextStyle(color: Colors.grey)),
      ];

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        scaffoldBackgroundColor: Colors.blue[100],
      ),
      home: Directionality(
        // textDirection: TextDirection.rtl,
        // textDirection: TextDirection.ltr,
        textDirection: Directionality.of(context) ?? TextDirection.ltr,
        child: Builder(
          builder: (BuildContext context) {
            double largeIconHeight = MediaQuery.of(context).size.width;
            double navBarHeight = scaledHeight(context, 85);
            double topOffset = (MediaQuery.of(context).size.height -
                    largeIconHeight -
                    MediaQuery.of(context).viewInsets.top -
                    (navBarHeight * 2)) /
                2;
            return Scaffold(
              floatingActionButton: FloatingActionButton(
                backgroundColor: logoColor,
                child: Icon(Icons.add),
                onPressed: _incrementBadge,
              ),
              appBar: AppBar(
                title: Text('Rolling Nav Bar: Tab ${activeIndex + 1}'),
              ),
              body: Stack(
                children: <Widget>[
                  Positioned(
                    top: topOffset,
                    height: largeIconHeight,
                    width: largeIconHeight,
                    child: GestureDetector(
                      onTap: incrementIndex,
                      child: ClipPolygon(
                        sides: 6,
                        borderRadius: 15,
                        child: Container(
                          height: largeIconHeight,
                          width: largeIconHeight,
                          color: logoColor,
                          child: Center(
                            child: Padding(
                              padding: EdgeInsets.fromLTRB(0, 100, 30, 0),
                              child: Transform(
                                transform: Matrix4.skew(0.1, -0.50),
                                child: Text(
                                  'Rolling\nNav Bar',
                                  textAlign: TextAlign.center,
                                  style: TextStyle(
                                    color: Colors.white,
                                    fontSize: scaledWidth(context, 63),
                                    fontFeatures: <FontFeature>[
                                      FontFeature.enable('smcp')
                                    ],
                                    shadows: <Shadow>[
                                      Shadow(
                                        offset: Offset(5, 5),
                                        blurRadius: 3.0,
                                        color: Color.fromARGB(255, 0, 0, 0),
                                      ),
                                      Shadow(
                                        offset: Offset(5, 5),
                                        blurRadius: 8.0,
                                        color: Color.fromARGB(125, 0, 0, 255),
                                      ),
                                    ],
                                  ),
                                ),
                              ),
                            ),
                          ),
                        ),
                      ),
                    ),
                  ),
                ],
              ),
              bottomNavigationBar: Container(
                height: navBarHeight,
                width: MediaQuery.of(context).size.width,
                // Option 1: Recommended
                child: RollingNavBar.iconData(
                  activeBadgeColors: <Color>[
                    Colors.white,
                  ],
                  activeIndex: activeIndex,
                  animationCurve: Curves.linear,
                  animationType: AnimationType.roll,
                  baseAnimationSpeed: 200,
                  badges: badgeWidgets,
                  iconData: iconData,
                  iconColors: <Color>[Colors.grey[800]],
                  iconText: iconText,
                  indicatorColors: indicatorColors,
                  iconSize: 25,
                  indicatorRadius: scaledHeight(context, 30),
                  onAnimate: _onAnimate,
                  onTap: _onTap,
                ),

                // Option 2: More complicated, but there if you need it
                // child: RollingNavBar.builder(
                //   builder: (
                //     BuildContext context,
                //     int index,
                //     AnimationInfo info,
                //     AnimationUpdate update,
                //   ) {
                //     return builderChildren[index];
                //   },
                //   badges: badgeWidgets.sublist(0, builderChildren.length),
                //   indicatorColors:
                //       indicatorColors.sublist(0, builderChildren.length),
                //   numChildren: builderChildren.length,
                //   onTap: _onTap,
                // ),
              ),
            );
          },
        ),
      ),
    );
  }
}