Change TextButton border colour - flutter - flutter

I have added a border to my TextButton.
TextButton(
style: ButtonStyle(
shape: MaterialStateProperty.all(RoundedRectangleBorder(
borderRadius: BorderRadius.circular(0)))),
onPressed: () {
replacePoints();
},
child: Text(
"${AppLocalizations.of(context)!.replacePoints} +",
style: TextStyle(color: Colors.white),
))
How can I change its colour (only outline colour not background)?


Try this:
TextButton(
style: ButtonStyle(
shape: MaterialStateProperty.all(RoundedRectangleBorder(
side: BorderSide(
color: Colors.red, // your color here
width: 1,
),
borderRadius: BorderRadius.circular(0)))),
onPressed: () {
replacePoints();
},
child: Text(
"${AppLocalizations.of(context)!.replacePoints} +",
style: TextStyle(color: Colors.white),
))


Try below code you will change Border color in two ways
Using TextButton.styleFrom refer styleFrom
TextButton(
style: TextButton.styleFrom(
side: BorderSide(
color: Colors.green,
),
),
onPressed: () {
//write your onPressed function here
print('Button Press');
},
child: Text(
'Hello, World!',
style: Theme.of(context).textTheme.headline4,
),
),
Result->
Using ButtonStyle Class refer ButtonStyle
TextButton(
style: ButtonStyle(
shape: MaterialStateProperty.all(
RoundedRectangleBorder(
side: BorderSide(
color: Colors.blue,
),
borderRadius: BorderRadius.circular(5),
),
),
),
onPressed: () {
//write your onPressed function here
print('Button Press');
},
child: Text(
'Hello, World!',
style: Theme.of(context).textTheme.headline4,
),
),
Result->

Related

how to change size and text color of the elevated buttons in flutter

how to change the size and text colour of the button in this code. the left side image shows my implementation so far. I want it to be changed to the right side image buttons.
Widget lbsButton() => Container(
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
ElevatedButton(
onPressed: () {
//playSound(soundNumber);
},
child: Text('lbs'),
style: ButtonStyle(
backgroundColor:
MaterialStateProperty.all<Color>(Colors.deepPurple),
),
),
SizedBox(
width: 10,
),
new ElevatedButton(
onPressed: () {},
child: Text('kg'),
style: ButtonStyle(
backgroundColor:
MaterialStateProperty.all<Color>(Colors.deepPurple),
),
)
],
),
);

If you want to enter the styles of the specific button that is ElevatedButton and its text, it could be as follows:
SizedBox( // Change the button size
width: 100,
height: 50,
child: ElevatedButton(
style: ElevatedButton.styleFrom( // ElevatedButton styles
primary: Colors.deepPurple,
padding: EdgeInsets.fromLTRB(20, 10, 20, 10), // Some padding example
shape: RoundedRectangleBorder( // Border
borderRadius: BorderRadius.circular(18.0),
side: BorderSide(color: Colors.red),
),
[...]
),
textStyle: TextStyle( // Text styles
color: Colors.white,
fontSize: 18,
overflow: TextOverflow.ellipsis,
[...]
),
onPressed: () {},
child: Text("lbs"),
),
),

Try like this
ElevatedButton(
onPressed: () {},
child: Text('kg',
style:TextStyle(color:Colors.black,fontSize:18),
),
style: ButtonStyle(
backgroundColor:
MaterialStateProperty.all<Color>(Colors.deepPurple),
),
);

You can try this also
FlatButton(
color: Colors.deepPurple[600],
child: const Text('lbs'),
textColor: Colors.white10,
onPressed: () {},
);
EDITED
Widget btn() => OutlinedButton(
child: const Text(
'lbs',
style: TextStyle(color: Colors.white),
),
style: OutlinedButton.styleFrom(
backgroundColor: Colors.deepPurple[600],
),
onPressed: () {},
);

Use ElevatedButton.styleFrom
Like so:
ElevatedButton(
style: ElevatedButton.styleFrom(
textStyle: TextStyle(color: Colors.white),
primary: Colors.purple,
shape: RoundedRectangleBorder
borderRadius: BorderRadius.circular(30),
),
),
);
Use primary to set the button color.
Use SizedBox to change the size.
Like so:
SizedBox(
width: 30,
height: 20,
child: ElevatedButton(
style: ElevatedButton.styleFrom(
textStyle: TextStyle(color: Colors.white),
primary: Colors.purple,
),
),
)
If you want the button to take the maximum width, use:
width: double.maxFinite

Replace deprecated RaisedButton with ElevatedButton

I used RaisedButton this way:
RaisedButton(shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24.0)),
onPressed: null,
padding: EdgeInsets.all(12.0),
color: Colors.blue,
child: Text("Button", style: TextStyle(color: Colors.white)))
They decided to make RaisedButton deprecated and ElevatedButton should be used instead. However, padding and shape properties are missing. How to get the same effect with ElevatedButton?

You can use the style property in the ElevatedButton, and then you can use ElevatedButton.styleFrom and in there you will find the properties like padding and shape.
Here is an example:
ElevatedButton(
style: ElevatedButton.styleFrom(
primary: Colors.blue,
elevation: 5,
padding: const EdgeInsets.all(12.0),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
),
),
onPressed: () {},
child: Text(
"Button",
style: TextStyle(color: Colors.white),
),
),

Just replace your code with this
ElevatedButton(
style: ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24.0)),
padding: const EdgeInsets.all(12.0),
primary: Colors.blue,
),
onPressed: null,
child: const Text('Button', style: TextStyle(color: Colors.white))),

Try this code hope its help to you its similar to RaisedButton
ElevatedButton(
onPressed: () {},
style: ElevatedButton.styleFrom(
fixedSize: Size(90, 15),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.all(
Radius.circular(24.0),
),
),
),
child: Text("ok"),
),
Your result screen->

Lets try with this and show side by side
Column(
children: [
RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(24.0)),
onPressed: null,
padding: EdgeInsets.all(12.0),
color: Colors.blue,
child:
Text("Button", style: TextStyle(color: Colors.white))),
SizedBox(
height: 10,
),
ElevatedButton(
style: ElevatedButton.styleFrom(
onPrimary: Colors.blue,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(24.0),
)),
onPressed: () {},
child: Container(
padding: const EdgeInsets.symmetric(horizontal: 12.0),
child:
Text("Button", style: TextStyle(color: Colors.white)),
)),
],
),
output:

Flutter change FlatButton textColor

in flutter and my application i'm trying to change some FlatButton text colors without using ThemeData, because in some part of application i want to have button with white text color or red,
how can i set this text colors normally?
for example:
FlatButton(
color: Colors.black,
textColor: Colors.white,
child: Text(
'login'
),
onPressed: () {}
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(50.0))),
FlatButton(
color: Colors.yellow,
textColor: Colors.red,
child: Text(
'login'
),
onPressed: () {}
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(50.0))),
FlatButton(
color: Colors.white,
textColor: Colors.green,
child: Text(
'login'
),
onPressed: () {}
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(50.0))),

Try TextStyle using inside the Text widget like below :
FlatButton(
color: Colors.yellow,
child: Text(
'login',style: TextStyle(color: Colors.red)
),
onPressed: () {}
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(50.0))),

I don't know why the textColor property isn't working for you, but try giving the child text widget style as I have shown below it will work.
FlatButton(
color: Colors.red,
textColor: Colors.green,
child: Text("This is a flatButton",
style: TextStyle(
color: Colors.white, //This will do the work
)),
onPressed: () {},
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(50.0)),
),

How to change OutlinedButton border color?

Flutter widget, I tried to change the OutlineButton border color by using BorderSide(color : Colors.blue). The OutlineButton always with grey color border no matter which color is set, but width change is applicable. How to change the OutlineButton border line color?
class OutlineButtonWidget extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Center(
child: OutlineButton(
onPressed: null,
borderSide: BorderSide(
width: 5.0,
color: Colors.blue,
style: BorderStyle.solid,
),
child: Text('outline button')
),
),
);
}
}

Use thestyle property:
OutlinedButton(
onPressed: () {},
child: Text('Outlined button'),
style: OutlinedButton.styleFrom(
side: BorderSide(width: 5.0, color: Colors.blue),
),
)

use style property
style: ButtonStyle(
side: MaterialStateProperty.all(BorderSide(
color: Colors.blue,
width: 1.0,
style: BorderStyle.solid)))
or try this both work
style: OutlinedButton.styleFrom(
side: BorderSide(
width: 5.0,
color: Colors.blue,
style: BorderStyle.solid,
),
),
child: Text('outline button')
)
OutlinedButton(
style: ButtonStyle(
side: MaterialStateProperty.all(BorderSide(
color: Colors.blue,
width: 1.0,
style: BorderStyle.solid))),
onPressed: () {},
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Align(
child: Padding(
padding:
const EdgeInsets.symmetric(horizontal: 12.0),
child: Icon(
Icons.clear,
size: 24,
),
),
),
Text("Clear")
],
))
result may like this

Style property will work
OutlineButton(
onPressed: (){},
style: OutlinedButton.styleFrom(
side: BorderSide(
width: 5.0,
color: Colors.blue,
style: BorderStyle.solid,
),
),
child: Text('outline button')
),
),

I was getting 'OutlineButton' is deprecated and shouldn't be used. Use OutlinedButton instead. See
the migration guide in flutter.dev/go/material-button-migration-guide).
Before migration code:
child: OutlineButton(
onPressed: onPressed,
child: CustomText(
text,
style: TextStyle(
fontWeight: FontWeight.w600,
fontSize: 14,
color: Colors.black),
),
color: Colors.orange,
borderSide: BorderSide(color: Colors.amber),
),
After migration code:
child: OutlinedButton(
onPressed: onPressed,
child: CustomText(
text,
style: TextStyle(
fontWeight: FontWeight.w600,
fontSize: 14,
color: Colors.black),
),
style: OutlinedButton.styleFrom(backgroundColor: Colors.orange, side: BorderSide(color: Colors.amber)),
),
Here is official ref of backgroundColor and color properties:
https://api.flutter.dev/flutter/material/ButtonStyle/backgroundColor.html
https://api.flutter.dev/flutter/material/MaterialButton/color.html

Theming
I wanted to avoid manually theming each OutlinedButton, and use theming instead.
You can do this with ThemeData's outlinedButtonTheme:
final color = ...;
ThemeData(
...
outlinedButtonTheme: OutlinedButtonThemeData(
style: ButtonStyle(
side: MaterialStateProperty.all(const BorderSide(color: color)),
// surfaceTintColor: MaterialStateProperty.all(Colors.blue),
)),
);

Create a rounded button / button with border-radius in Flutter

I'm currently developing an Android app in Flutter. How can I add a rounded button?

1. Solution Summary
FlatButton and RaisedButton are deprecated.
So, you can use shape which placed in the style property, for TextButton and ElevatedButton.
There are some changes since Flutter 2.0:
style: the property type has changed to ButtonStyle
shape: the property type has changed to MaterialStateProperty<T>
2. Rounded Button
Inside the style property exists the shape property:
style: ButtonStyle(
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
side: BorderSide(color: Colors.red)
)
)
)
Square Button
For a square button you can use ElevatedButton or otherwise add:
style: ButtonStyle(
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.zero,
side: BorderSide(color: Colors.red)
)
)
)
Complete Example
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: [
TextButton(
child: Text(
"Add to cart".toUpperCase(),
style: TextStyle(fontSize: 14)
),
style: ButtonStyle(
padding: MaterialStateProperty.all<EdgeInsets>(EdgeInsets.all(15)),
foregroundColor: MaterialStateProperty.all<Color>(Colors.red),
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
side: BorderSide(color: Colors.red)
)
)
),
onPressed: () => null
),
SizedBox(width: 10),
ElevatedButton(
child: Text(
"Buy now".toUpperCase(),
style: TextStyle(fontSize: 14)
),
style: ButtonStyle(
foregroundColor: MaterialStateProperty.all<Color>(Colors.white),
backgroundColor: MaterialStateProperty.all<Color>(Colors.red),
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.zero,
side: BorderSide(color: Colors.red)
)
)
),
onPressed: () => null
)
]
)

Update
Since the left-sided buttons are now deprecated, use the right-sided ones.
Deprecated --> Recommended
RaisedButton --> ElevatedButton
OutlineButton --> OutlinedButton
FlatButton --> TextButton
ElevatedButton
Using StadiumBorder
ElevatedButton(
onPressed: () {},
child: Text('Button'),
style: ElevatedButton.styleFrom(shape: StadiumBorder()),
)
Using RoundedRectangleBorder
ElevatedButton(
onPressed: () {},
child: Text('Button'),
style: ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(12), // <-- Radius
),
),
)
Using CircleBorder
ElevatedButton(
onPressed: () {},
child: Text('Button'),
style: ElevatedButton.styleFrom(
shape: CircleBorder(),
padding: EdgeInsets.all(24),
),
)
Using BeveledRectangleBorder
ElevatedButton(
onPressed: () {},
child: Text('Button'),
style: ElevatedButton.styleFrom(
shape: BeveledRectangleBorder(
borderRadius: BorderRadius.circular(12)
),
),
)
OutlinedButton
Using StadiumBorder
OutlinedButton(
onPressed: () {},
child: Text('Button'),
style: OutlinedButton.styleFrom(
shape: StadiumBorder(),
),
)
Using RoundedRectangleBorder
OutlinedButton(
onPressed: () {},
child: Text('Button'),
style: OutlinedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(12),
),
),
)
Using CircleBorder:
OutlinedButton(
onPressed: () {},
child: Text('Button'),
style: OutlinedButton.styleFrom(
shape: CircleBorder(),
padding: EdgeInsets.all(24),
),
)
Using BeveledRectangleBorder
OutlinedButton(
onPressed: () {},
child: Text('Button'),
style: OutlinedButton.styleFrom(
shape: BeveledRectangleBorder(
borderRadius: BorderRadius.circular(12),
),
),
)
TextButton
TextButton also works similar to ElevatedButton and OutlinedButton, however, you can only see the shapes when the button is pressed.

You can use the ElevatedButton Widget. The elevated button widget has a shape property which you can use as shown in the below snippet.
ElevatedButton(
style: ButtonStyle(
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
side: BorderSide(
color: Colors.teal,
width: 2.0,
),
),
),
),
child: Text('Submit'),
onPressed: () {},
),

Since September 2020, Flutter 1.22.0:
Both "RaisedButton" and "FlatButton" are deprecated.
The most up-to-date solution is to use new buttons:
1. ElevatedButton:
Code:
ElevatedButton(
child: Text("ElevatedButton"),
onPressed: () => print("it's pressed"),
style: ElevatedButton.styleFrom(
primary: Colors.red,
onPrimary: Colors.white,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(32.0),
),
),
)
Don't forget, there's also an .icon constructor to add an icon easily:
ElevatedButton.icon(
icon: Icon(Icons.thumb_up),
label: Text("Like"),
onPressed: () => print("it's pressed"),
style: ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(32.0),
),
),
)
2. OutlinedButton:
Code:
OutlinedButton.icon(
icon: Icon(Icons.star_outline),
label: Text("OutlinedButton"),
onPressed: () => print("it's pressed"),
style: ElevatedButton.styleFrom(
side: BorderSide(width: 2.0, color: Colors.blue),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(32.0),
),
),
)
3. TextButton:
You can always use TextButton if you don't want an outline or color fill.

You can simply use RaisedButton
Padding(
padding: EdgeInsets.only(left: 150.0, right: 0.0),
child: RaisedButton(
textColor: Colors.white,
color: Colors.black,
child: Text("Search"),
onPressed: () {},
shape: new RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(30.0),
),
),
)
Output:
More info: RSCoder

You can simply use RaisedButton or you can use InkWell to get a custom button and also properties like onDoubleTap, onLongPress, etc.:
new InkWell(
onTap: () => print('hello'),
child: new Container(
//width: 100.0,
height: 50.0,
decoration: new BoxDecoration(
color: Colors.blueAccent,
border: new Border.all(color: Colors.white, width: 2.0),
borderRadius: new BorderRadius.circular(10.0),
),
child: new Center(child: new Text('Click Me', style: new TextStyle(fontSize: 18.0, color: Colors.white),),),
),
),
If you want to use the splashColor and highlightColor properties in the InkWell widget, use the Material widget as the parent of the InkWell widget instead of decorating the container (deleting the decoration property). Read about why here.

Different ways to create a rounded button are as follows:
ElevatedButton with ElevatedButton.styleFrom
ElevatedButton(
style: ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
),
),
onPressed: () {},
child:
Text("Buy now".toUpperCase(), style: TextStyle(fontSize: 14)),
),
ElevatedButton with ButtonStyle
ElevatedButton(
style: ButtonStyle(
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(50.0),
))),
onPressed: () {},
child: Text("Submit".toUpperCase()),
),
A practical demonstration of a round button can be found in the below Dartpad link:
Rounded Button Demo Examples on DartPad

You can use the below code to make a rounded button with a gradient color.
Container(
width: 130.0,
height: 43.0,
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(30.0),
gradient: LinearGradient(
// Where the linear gradient begins and ends
begin: Alignment.topRight,
end: Alignment.bottomLeft,
// Add one stop for each color. Stops should increase from 0 to 1
stops: [0.1, 0.9],
colors: [
// Colors are easy thanks to Flutter's Colors class.
Color(0xff1d83ab),
Color(0xff0cbab8),
],
),
),
child: FlatButton(
child: Text(
'Sign In',
style: TextStyle(
fontSize: 16.0,
fontFamily: 'Righteous',
fontWeight: FontWeight.w600,
),
),
textColor: Colors.white,
color: Colors.transparent,
shape:
RoundedRectangleBorder(borderRadius: BorderRadius.circular(30.0)),
onPressed: () {
},
),
);

Use TextButton instead.
Buttons like the FlatButton, RaisedButton and OutlineButton has been said to be deprecated since October 2020. This is one of the Flutter development team's effort to simplify and make the Flutter API consistent, you can customize its style by using style property.
TextButton(
child: Padding(
padding: const EdgeInsets.only(left: 10.0, right: 10.0),
child: Text('Text here',
style: TextStyle(
color: Colors.teal,
fontSize: 14,
fontWeight: FontWeight.w500)),
),
style: TextButton.styleFrom(
primary: Colors.teal,
onSurface: Colors.yellow,
side: BorderSide(color: Colors.teal, width: 2),
shape: const RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(25))),
),
onPressed: () {
print('Pressed');
},
),

you can use this code:
ElevatedButton(
onPressed: () {},
style: ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(borderRadius))),
),
child: Text("ok"),
)

To use any shape in your button, make sure you perform all the code inside the Button widget:
**shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(18.0),
side: BorderSide(color: Colors.red) ),**
If you want make it is square, use BorderRadius.circular(0.0) It automatically makes it into a square.
The button is like this:
Here is the all source code for the give UI screen:
Scaffold(
backgroundColor: Color(0xFF8E44AD),
body: new Center(
child: Column(
children: <Widget>[
Container(
margin: EdgeInsets.fromLTRB(90, 10, 20, 0),
padding: new EdgeInsets.only(top: 92.0),
child: Text(
"Currency Converter",
style: TextStyle(
fontSize: 48,
fontWeight: FontWeight.bold,
color: Colors.white,
),
),
),
Container(
margin: EdgeInsets.only(),
padding: EdgeInsets.all(25),
child: TextFormField(
decoration: new InputDecoration(
filled: true,
fillColor: Colors.white,
labelText: "Amount",
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
),
),
),
),
Container(
padding: EdgeInsets.all(25),
child: TextFormField(
decoration: new InputDecoration(
filled: true,
fillColor: Colors.white,
labelText: "From",
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
),
),
),
),
Container(
padding: EdgeInsets.all(25),
child: TextFormField(
decoration: new InputDecoration(
filled: true,
fillColor: Colors.white,
labelText: "To",
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(10),
)),
),
),
SizedBox(height: 20.0),
MaterialButton(
height: 58,
minWidth: 340,
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(12)),
onPressed: () {},
child: Text(
"CONVERT",
style: TextStyle(
fontSize: 24,
color: Colors.black,
),
),
color: Color(0xFFF7CA18),
),
],
),
),
),
);

You can use this code for a transparent rounded button by passing a transparent color to the color property inside BoxDecoration.
eg. color: Colors.transparent.
Also, take note that this button makes use of only the Container and GestureDetector widgets.
Container(
height: 50.0,
child: GestureDetector(
onTap: () {},
child: Container(
decoration: BoxDecoration(
border: Border.all(
color: Color(0xFFF05A22),
style: BorderStyle.solid,
width: 1.0,
),
color: Colors.transparent,
borderRadius: BorderRadius.circular(30.0),
),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Center(
child: Text(
"BUTTON",
style: TextStyle(
color: Color(0xFFF05A22),
fontFamily: 'Montserrat',
fontSize: 16,
fontWeight: FontWeight.w600,
letterSpacing: 1,
),
),
)
],
),
),
),
)

In the new update flutter 3.0 flutter uses Material 3 guidelines.
According to which the default border of buttons are rounded.
Default Button
ElevatedButton(
onPressed: () {}, child: const Text("Default Button ")),
Button with Border Radius Zero
ElevatedButton(
style: ElevatedButton.styleFrom(
shape: const RoundedRectangleBorder(
borderRadius: BorderRadius.zero)),
onPressed: () {},
child: const Text("Border Radius Zero ")),
Button with custom border radius
ElevatedButton(
style: ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(50))),
onPressed: () {},
child: const Text("Border Radius Custom ")),
Note: You can use the same logic for FilledButton, TextButton and the like.
Refer https://m3.material.io/components/all-buttons for button style.

If anybody is looking for complete circular button then I achieved it this way:
Center(
child: SizedBox.fromSize(
size: Size(80, 80), // Button width and height
child: ClipOval(
child: Material(
color: Colors.pink[300], // Button color
child: InkWell(
splashColor: Colors.yellow, // splash color
onTap: () {}, // Button pressed
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Icon(Icons.linked_camera), // Icon
Text("Picture"), // Text
],
),
),
),
),
),
)

After the Null safety, use ElevatedButton not RaisedButton because RaisedButton is depreciated as the docs says.
child: ElevatedButton(
onPressed: () {},
child: const Text('Add item to the list'),
style: ButtonStyle(
backgroundColor:
MaterialStateProperty.all<Color>(Common.buttonColor),
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
),
),
),
),

RaisedButton(
child: Text("Button"),
onPressed: (){},
shape: RoundedRectangleBorder(borderRadius: new BorderRadius.circular(30.0),
side: BorderSide(color: Colors.red))
)

One of the simplest ways to create a rounded button is to use a FlatButton and then specify the roundness by setting its shape property. Follow the code below
FlatButton(
padding: EdgeInsets.all(30.0),
color: Colors.black,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(20.0)),
child: child: Text(
"Button",
style: TextStyle(color: Colors.white),
),
onPressed: () {
print('Button pressed');
},
),
Note: In order to change the roundness adjust the value inside BorderRadius.circular()

Here is the code for your problem. You just have to take a simple container with a border radius in boxdecoration.
new Container(
alignment: Alignment.center,
decoration: BoxDecoration(
borderRadius: BorderRadius.all(Radius.circular(15.0)),
color: Colors.blue,
),
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding: const EdgeInsets.all(10.0),
child: new Text(
"Next",
style: new TextStyle(
fontWeight: FontWeight.w500,
color: Colors.white,
fontSize: 15.0,
),
),
),
],
),
),

You can also use ButtonTheme():
Here is example code -
ButtonTheme(
minWidth: 200.0,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(18.0),
side: BorderSide(color: Colors.green)),
child: RaisedButton(
elevation: 5.0,
hoverColor: Colors.green,
color: Colors.amber,
child: Text(
"Place Order",
style: TextStyle(
color: Colors.white, fontWeight: FontWeight.bold),
),
onPressed: () {},
),
),

Now we have an Icon button to achieve a rounded button click and overlay. However, the background color is not yet available, but the same can be achieved by the Circle avatar widget as follows:
CircleAvatar(
backgroundColor: const Color(0xffF4F3FA),
child: IconButton(
onPressed: () => FlushbarHelper.createInformation(
message: 'Work in progress...')
.show(context),
icon: Icon(Icons.more_vert),
),
),

New Elevate Button
Style
customElevatedButton({radius, color}) => ElevatedButton.styleFrom(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(radius == null ? 100 : radius),
),
primary: color,
);
Icon
Widget saveIcon() => iconsStyle1(
Icons.save,
);
// Common icon style
iconsStyle1(icon) => Icon(
icon,
color: white,
size: 15,
);
Button use
ElevatedButton.icon(
icon: saveIcon(),
style:
customElevatedButton(color: Colors.green[700]),
label: Text('Save',
style: TextStyle(color: Colors.white)),
onPressed: () {
},
),

If you want to Use MaterialButton then,
=======================================
You can add RoundedRectangleBorder Given in Shape Like this,
MaterialButton(
onPressed: () {},
minWidth: MediaQuery.of(context).size.width * 0.4,
height: 34,
color: colorWhite,
highlightColor: colorSplash,
splashColor: colorSplash,
visualDensity: VisualDensity.compact,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(4),
side: BorderSide(
color: colorGrey,
width: 0.6,
),
),
child: Text("CANCEL"),
),

You can create a custom view and put it inside a GestureDetector for it to behave like a button. The benefit is that you can provide endless types of custom decoration (including making it round with specified radius) to the container.

Here is another solution:
Container(
height: MediaQuery.of(context).size.height * 0.10,
width: MediaQuery.of(context).size.width,
child: ButtonTheme(
minWidth: MediaQuery.of(context).size.width * 0.75,
child: RaisedButton(
shape: RoundedRectangleBorder(
borderRadius: new BorderRadius.circular(25.0),
side: BorderSide(color: Colors.blue)),
onPressed: () async {
// Do something
},
color: Colors.red[900],
textColor: Colors.white,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Text("Button Text,
style: TextStyle(fontSize: 24)),
),
),
),
),

Another cool solution that works in 2021:
TextButton(
child: Padding(
padding: const EdgeInsets.all(5.0),
child: Text('Follow Us'.toUpperCase()),
),
style: TextButton.styleFrom(
backgroundColor: Colors.amber,
shadowColor: Colors.red,
elevation: 2,
textStyle: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(5.0),)
),
onPressed: () {
print('Pressed');
},
),

With Flutter version 2, try this
ElevatedButton(
style: ButtonStyle(
shape: MaterialStateProperty.all<OutlinedBorder>(
RoundedRectangleBorder(
side:
BorderSide(width: 1.0, color: Colors.red,
borderRadius:
BorderRadius.circular(5.0),),),
backgroundColor: MaterialStateProperty.all<Color>(Colors.red),
foregroundColor: MaterialStateProperty.all<Color>(Colors.green),
elevation:
MaterialStateProperty.all<double>(8.0),
padding: MaterialStateProperty.all<EdgeInsetsGeometry>(
const EdgeInsets.symmetric(
horizontal: 15.0,
vertical: 10.0),),),
onPressed: (){},
child: Text('Button'),)

Container(
width: yourWidth,
height: yourHeight ,
decoration: BoxDecoration(
borderRadius: radius,
gradient: yourGradient,
border: yourBorder),
child: FlatButton(
onPressed: {} (),
shape: RoundedRectangleBorder(borderRadius: radius),
.......
and use the same radius.

In Flutter, the Container() widget is used for styling your widget. Using the Container() widget, you can set a border or rounded corner of any widget.
If you want to set any type of styling and set the decoration, put that widget into the Container() widget. That provides many properties to the decoration.
Container(
width: 100,
padding: EdgeInsets.all(10),
alignment: Alignment.center,
decoration: BoxDecoration(
color: Colors.blueAccent,
borderRadius: BorderRadius.circular(30)), // Make rounded corner
child: Text("Click"),
)

addButton() {
return Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding: const EdgeInsets.symmetric(vertical: 10.0),
child: SizedBox(
height: 45,
width: 200,
child: ElevatedButton.icon(
onPressed: () async {},
style: ButtonStyle(
shape: MaterialStateProperty.all<RoundedRectangleBorder>(
RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
)),
elevation: MaterialStateProperty.all(1),
backgroundColor: MaterialStateProperty.all(Colors.blue),
),
icon: Icon(Icons.add, size: 18),
label: Text("Add question"),
),
),
),
],
);
}

you can use this style for your elevatedButton to make it circular
style: ButtonStyle(
elevation: MaterialStateProperty.all(8.0),
backgroundColor:
MaterialStateProperty.all(Constants().orangeColor),
textStyle: MaterialStateProperty.all(
TextStyle(
fontSize: 16.0,
),
),
shape: MaterialStateProperty.all<CircleBorder>(
CircleBorder(),
),
shadowColor: MaterialStateProperty.all(Constants().orangeColor),
),