how to change border radius of elevated button flutter - flutter

Question

I have created two buttons in a row using flutter. now I want to change border-radius o=f buttons. how can I do this properly? the picture shows the buttons I was created.
Widget lbsButton() => Container(
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
SizedBox(
width: 80,
height:50,
child: ElevatedButton(
onPressed: () {},
child: Text('lbs'),
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all<Color>(mainPurpleText),
),
),
),
SizedBox(
width: 10,
),
SizedBox(
width: 80,
height:50,
child: new ElevatedButton(
onPressed: () {},
child: Text('kg' , style:TextStyle(color:Colors.grey,fontSize:13),
),
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all<Color>( Colors.white),
),
),
)
],
),
);

Answer 1

return ElevatedButton(
onPressed: onPressed,
child: Text('test'),
style: ButtonStyle(
shape: MaterialStateProperty.all(
RoundedRectangleBorder(
// Change your radius here
borderRadius: BorderRadius.circular(16),
),
),
),
);

Answer 2

The elevated button widget has a shape property which you can use as shown in the below snippet.
ElevatedButton(
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all<Color>(mainPurpleText),
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20.0),
),
),
),
child: Text('Submit'),
onPressed: () {},
),

Answer 3

You can apply ElevatedButton.stylefrom() on the "style" property of ElevatedButton.
ElevatedButton(
style: ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(40),
),
),
onPressed: () {},
child: Text('kg'),
)

Answer 4

You can use ButtonStyle and I think it is kind of similar Create a rounded button / button with border-radius in Flutter.
style: ButtonStyle(
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius:
BorderRadius.circular(18.0), // radius you want
side: BorderSide(
color: Colors.transparent, //color
),
)),