A Flutter Package Which Implements A ConvexAppBar

The official BottomAppBar can only display a notch FAB with an app bar, and sometimes we need a convex FAB. BottomAppBar and NotchShape's implementation inspires this ConvexAppBar.

Online example can be found at https://appbar.codemagic.app.

convex_bottom_bar is now a Flutter Favorite package!

Here are some supported style:

fixed	react	badge chip
fixedCircle	reactCircle	flip
textIn	titled	tab image
button	fixed corner

How to use

Typically ConvexAppBar can work with Scaffold by setup its bottomNavigationBar.

The ConvexAppBar has two constructors. The ConvexAppBar() will use the default style to simplify the tab creation.

Add this to your package's pubspec.yaml file, use the latest version :

dependencies:
  convex_bottom_bar: ^latest_version

import 'package:convex_bottom_bar/convex_bottom_bar.dart';

Scaffold(
  bottomNavigationBar: ConvexAppBar(
    items: [
      TabItem(icon: Icons.home, title: 'Home'),
      TabItem(icon: Icons.map, title: 'Discovery'),
      TabItem(icon: Icons.add, title: 'Add'),
      TabItem(icon: Icons.message, title: 'Message'),
      TabItem(icon: Icons.people, title: 'Profile'),
    ],
    onTap: (int i) => print('click index=$i'),
  )
);

Flutter Version Support
As Flutter is developing fast. There can be breaking changes. We will be trying to support the stable version and beta version through different package versions.

Features

• Provide multiple internal styles
• Ability to change the theme of AppBar
• Provide builder API to customize a new style
• Add badge on the tab menu
• Elegant transition animation
• Provide hook API to override some of the internal styles
• RTL support

Table of contents

• Theming
• Badge
• Single Button
• Style Hook
• RTL Support
• Custom Example
• FAQ
• Donate

Theming

The bar will use default style, you may want to theme it. Here are some supported attributes:

Badge

If you need to add a badge on the tab, use the ConvexAppBar.badge to get it done.

ConvexAppBar.badge({0: '99+', 1: Icons.assistant_photo, 2: Colors.redAccent},
  items: [
    TabItem(icon: Icons.home, title: 'Home'),
    TabItem(icon: Icons.map, title: 'Discovery'),
    TabItem(icon: Icons.add, title: 'Add'),
  ],
  onTap: (int i) => print('click index=$i'),
);

The badge() method accepts an array of badges; The badges is a map with tab items. Each value of entry can be either String, IconData, Color or Widget.

Single Button

If you only need a single button, checkout the ConvexButton.

Scaffold(
  appBar: AppBar(title: const Text('ConvexButton Example')),
  body: Center(child: Text('count $count')),
  bottomNavigationBar: ConvexButton.fab(
    onTap: () => setState(() => count++),
  ),
);

Style Hook

Hook for internal tab style. Unlike the ConvexAppBar.builder, you may want to update the tab style without defining a new tab style.

Warning:
This hook is limited and can lead to overflow broken if the size you provide does not match with internal style.

StyleProvider(
  style: Style(),
  child: ConvexAppBar(
    initialActiveIndex: 1,
    height: 50,
    top: -30,
    curveSize: 100,
    style: TabStyle.fixedCircle,
    items: [
      TabItem(icon: Icons.link),
      TabItem(icon: Icons.import_contacts),
      TabItem(title: "2020", icon: Icons.work),
    ],
    backgroundColor: _tabBackgroundColor,
  ),
)
class Style extends StyleHook {
  @override
  double get activeIconSize => 40;

  @override
  double get activeIconMargin => 10;

  @override
  double get iconSize => 20;

  @override
  TextStyle textStyle(Color color) {
    return TextStyle(fontSize: 20, color: color);
  }
}

RTL Support

RTL is supported internally, and if you define the TextDirection inside the app, the AppBar should work fine. Both RTL and LTR can be configured through Directionality:

Directionality(
  textDirection: TextDirection.rtl,
  child: Scaffold(body:ConvexAppBar(/*TODO ...*/)),
)

Custom Example

If the default style does not match your situation, try with ConvexAppBar.builder(), allowing you to custom nearly all the tab features.

Scaffold(
  bottomNavigationBar: ConvexAppBar.builder(
    count: 5,
    backgroundColor: Colors.blue,
    itemBuilder: Builder(),
  )
);

// user defined class
class Builder extends DelegateBuilder {
  @override
  Widget build(BuildContext context, int index, bool active) {
    return Text('TAB $index');
  }
}

Full custom example can be found at example.

FAQ

Please file feature requests and bugs at the issue tracker.

• How to block tab event?
• Crash on flutter dev/beta channel
• Change active tab index programmatically
• Using an image instead of an icon for actionItem
• Is there anyway to remove elevation in the bottom bar?

Use this package as a library

Depend on it

Run this command:

With Flutter:

 $ flutter pub add convex_bottom_bar

This will add a line like this to your package's pubspec.yaml (and run an implicit flutter pub get):

dependencies:
  convex_bottom_bar: ^3.2.0

Alternatively, your editor might support flutter pub get. Check the docs for your editor to learn more.

Import it

Now in your Dart code, you can use:

import 'package:convex_bottom_bar/convex_bottom_bar.dart';

example/lib/main.dart

/*
 *  Copyright 2020 chaobinwu89@gmail.com
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

import 'package:convex_app_bar_example/convex_button_demo.dart';
import 'package:convex_app_bar_example/custom_appbar_sample.dart';
import 'package:convex_bottom_bar/convex_bottom_bar.dart';
import 'package:flutter/material.dart';

import 'default_appbar_demo.dart';

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

class MyApp extends StatefulWidget {
  @override
  State createState() => _State();
}

class _State extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      initialRoute: "/",
      routes: {
        "/": (_) => HelloConvexAppBar(),
        "/bar": (BuildContext context) => DefaultAppBarDemo(),
        "/custom": (BuildContext context) => CustomAppBarDemo(),
        "/fab": (BuildContext context) => ConvexButtonDemo(),
      },
    );
  }
}

class HelloConvexAppBar extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Hello ConvexAppBar')),
      body: Center(
          child: TextButton(
        child: Text('Click to show full example'),
        onPressed: () => Navigator.of(context).pushNamed('/bar'),
      )),
      bottomNavigationBar: ConvexAppBar(
        style: TabStyle.react,
        items: [
          TabItem(icon: Icons.list),
          TabItem(icon: Icons.calendar_today),
          TabItem(icon: Icons.assessment),
        ],
        initialActiveIndex: 1,
        onTap: (int i) => print('click index=$i'),
      ),
    );
  }
}

Download details:

Author: hacktons.cn

Source: https://github.com/hacktons/convex_bottom_bar

#flutter #android #ios #web-development #widgets #bar #ui