Circle around number - flutter

Question

I'd like to draw a circle around a number on top of an image. So the inside of the circle is transparent and the border of the circle is white. Alas, the double CircleAvatar trick to have a CircleAvatar's border doesn't work for transparent background. An example can be found here https://drive.google.com/file/d/1QFIH9ty8cajoLlI9-Vv3q4mOscRLRvAf/view
Stack(
children: <Widget>[
Image.network(
this.widget.rando.etapes[index].couvertureUrl,
width: 90.0,
height: 90.0,
fit:BoxFit.cover),
Container(
width: 90.0,
alignment: Alignment.center,
child: Container(
child:CircleAvatar(
backgroundColor: Colors.transparent,
radius: 30,
child: Text((index+1).toString(),
style:TextStyle(color: Colors.white,
fontSize: 25.0,
fontWeight: FontWeight.w600)),
),
),
)
]
),

Answer 1

You can do it by using 'Container' and decoration parameter instead of 'CircleAvatar'.
Here is a my test code.
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
void initState() {
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: _buildBody(),
floatingActionButton: FloatingActionButton(
onPressed: () {},
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
Widget _buildBody() {
return Container(
height: 190,
width: 190,
child: Stack(
children: <Widget>[
Image.network(
'https://images.unsplash.com/photo-1441974231531-c6227db76b6e?ixid=MXwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHw%3D&ixlib=rb-1.2.1&auto=format&fit=crop&w=1351&q=80',
width: 190.0,
height: 190.0,
fit: BoxFit.cover),
Center(
child: Container(
width: 90.0,
height: 90.0,
decoration: BoxDecoration(
color: Colors.transparent,
shape: BoxShape.circle,
border: Border.all(
color: Colors.white,
width: 5.0,
style: BorderStyle.solid,
),
),
child: Center(
child: Text(
'1',
style: TextStyle(
color: Colors.white,
fontSize: 25.0,
fontWeight: FontWeight.w600,
),
),
),
),
),
],
),
);
}
}