A Flutter package implements a convex BottomAppBar

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This package extends the official BottomAppBar to display a convex tab, example can be preview as bellow.


Language: English 中文简体


The official BottomAppBar can only display a notch FAB with app bar, sometimes we need a convex FAB. This ConvexAppBar is inspired by BottomAppBar and NotchShape’s implementation.


Install Demo app-release.apk

How to use

Typically ConvexAppBar can work with Scaffold by setup its bottomNavigationBar.

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

  bottomNavigationBar: ConvexAppBar(
    items: TAB_ITEMS,
    onTap: (int i) => setState(() {
      _selectedIndex = i;
    actionItem: const TabItem(icon: Icons.add, title: "Publish"),
    onTapActionButton: () => setState(() {
      _selectedIndex = -1;

Thanks to he GFW, this project is not published yet. Add dependence as bellow:

      url: https://github.com/hacktons/convex_bottom_bar.git
      ref: 1.0.0

Table of contents


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

Attributes Description
backgroundColor AppBar background
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

Custom Example

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

Here is a custom sample: custom preview

  bottomNavigationBar: ConvexAppBar.builder(
    count: items.length,
    backgroundColor: _tabBackgroundColor,
    tabBuilder: (BuildContext context, int index, bool active) {
      var navigationItem = items[index];
      var _color = active ? Colors.white : Colors.white60;
      var _icon = active
          ? navigationItem.activeIcon ?? navigationItem.icon
          : navigationItem.icon;
      return Container(
        color: Colors.transparent,
        padding: EdgeInsets.only(bottom: 2),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.end,
          children: <Widget>[
            Icon(_icon, color: _color),
            Text(navigationItem.title, style: TextStyle(color: _color))
    actionBuilder: (BuildContext context, int index, bool active) {
      var _color = active ? Colors.white : Colors.white60;
      return Stack(
        alignment: Alignment.center,
        children: <Widget>[
            width: 60,
            height: 60,
            child: Container(
                  BoxDecoration(shape: BoxShape.circle, color: _color),
              child: Icon(
                size: 40,
                color: _tabBackgroundColor,


Please file feature requests and bugs at the issue tracker.


For more detail, please refer to the example project.

Github主页 👉hacktons/convex_bottom_bar