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'),
],
initialActiveIndex: 2,//optional, default as 0
onTap: (int i) => print('click index=$i'),
)
);
Flutter Version Support
As Flutter is developing fast. There can be breaking changes. We will be trying to support the stable version and beta version through different package versions.
| Stable Flutter Version | Package Version | More |
|---|---|---|
| >=1.20 | >=2.4.0 | Since v1.20, the stable version changed the Stack api |
| <1.20 | <=2.3.0 | Support for stable version such as v1.17, v1.12 is not going to be updated |
Features
- Provide multiple internal styles
- Ability to change the theme of AppBar
- Provide builder API to customize a new style
- Add badge on the tab menu
- Elegant transition animation
- Provide hook API to override some of the internal styles
- RTL support
Table of contents
Theming
The bar will use default style, you may want to theme it. Here are some supported attributes:
| Attributes | Description |
|---|---|
| backgroundColor | AppBar background |
| gradient | gradient will override backgroundColor |
| height | AppBar height |
| color | tab icon/text color |
| activeColor | tab icon/text color when selected |
| curveSize | size of the convex shape |
| top | top edge of the convex shape relative to AppBar |
| cornerRadius | draw the background with topLeft and topRight corner; Only work with fixed tab style |
| style | style to describe the convex shape: fixed, fixedCircle, react, reactCircle, ... |
| chipBuilder | custom badge builder, use ConvexAppBar.badge for default badge |
Badge
If you need to add a badge on the tab, use the ConvexAppBar.badge to get it done.
ConvexAppBar.badge({0: '99+', 1: Icons.assistant_photo, 2: Colors.redAccent},
items: [
TabItem(icon: Icons.home, title: 'Home'),
TabItem(icon: Icons.map, title: 'Discovery'),
TabItem(icon: Icons.add, title: 'Add'),
],
onTap: (int i) => print('click index=$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,
style: TabStyle.fixed,
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?
Donate
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When I click on the addButton (onTap) the color of the title "Overview" turns white, because the addButton is now the selected button. The icon stays at my primaryColor (purple).
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