How to remove padding of MaterialBanner? - flutter

Question

I want to remove the following blue padding from MaterialBanner widget, but it doesn't seem to be customizable. I want to insert an image in the red region.
I looked into MaterialBanner for using across Scaffold widgets because ScaffoldMessenger doesn't allow me to insert widgets other than MaterialBanner.
Is there any suggestion?
dartpad.
import 'package:flutter/material.dart';
void main() {
runApp(MaterialApp(home: Scaffold(body: JustBanner())));
}
class JustBanner extends StatefulWidget {
#override
State<StatefulWidget> createState() {
return _JustBannerState();
}
}
class _JustBannerState extends State<JustBanner> {
#override
Widget build(BuildContext context) {
return Column(
children: [
ElevatedButton(
onPressed: () {
final messenger = ScaffoldMessenger.of(context);
messenger.clearMaterialBanners();
messenger.showMaterialBanner(MaterialBanner(
padding: EdgeInsets.zero,
leadingPadding: EdgeInsets.zero,
leading: const SizedBox.shrink(),
backgroundColor: Colors.blue,
content: Container(
color: Colors.red,
width: 200,
height: 50,
),
actions: const [SizedBox.shrink()]));
},
child: const Text('Banner')),
],
);
}
}

Answer 1

Container(
width: MediaQuery.of(context).size.width,
child: MaterialBanner(
content: Text('Hello'),
actions: [
Icon(Icons.add),
],
),
),

Answer 2

Its no possible without copy and re-create the class, buttonBar always appear:
final Widget buttonBar = Container( // <-- problematic widget
alignment: AlignmentDirectional.centerEnd,
constraints: const BoxConstraints(minHeight: 52.0),
padding: const EdgeInsets.symmetric(horizontal: 8),
child: OverflowBar(
overflowAlignment: widget.overflowAlignment,
spacing: 8,
children: widget.actions,
),
);
final double elevation = widget.elevation ?? bannerTheme.elevation ?? 0.0;
final Color backgroundColor = widget.backgroundColor
?? bannerTheme.backgroundColor
?? theme.colorScheme.surface;
final TextStyle? textStyle = widget.contentTextStyle
?? bannerTheme.contentTextStyle
?? theme.textTheme.bodyText2;
Widget materialBanner = Container(
margin: EdgeInsets.only(bottom: elevation > 0 ? 10.0 : 0.0),
child: Material(
elevation: elevation,
color: backgroundColor,
child: Column(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
Padding(
padding: padding,
child: Row(
children: <Widget>[
if (widget.leading != null)
Padding(
padding: leadingPadding,
child: widget.leading,
),
Expanded(
child: DefaultTextStyle(
style: textStyle!,
child: widget.content,
),
),
if (isSingleRow)
buttonBar, // <----- here
],
),
),
if (!isSingleRow)
buttonBar, // <----- here
if (elevation == 0)
const Divider(height: 0),
],
),
),
);