ToggleButtons, Flutter: How to change border color and border radius

Question

I have 3 ToggleButtons and I'm trying to figure out how to change the color of the selected button's border. As you can see in my picture, the green button on the left has a very hard to see light blue border around it since it is the selected button. I would like to know how I can change this color and also how I can round the border's corners.

If it helps, 'CryptoCard' is made with the Card class.

Here is my code:

Center(
                          child: ToggleButtons(
                              borderWidth: 0,
                              splashColor: Colors.yellow,
                              renderBorder: false,
                              children: <Widget>[
                                CryptoCard(
                                    selectedCurrency,
                                    snapshot.connectionState ==
                                            ConnectionState.waiting
                                        ? '---'
                                        : coinData[0],
                                    'Bitcoin'),
                                CryptoCard(
                                    selectedCurrency,
                                    snapshot.connectionState ==
                                            ConnectionState.waiting
                                        ? '---'
                                        : coinData[1],
                                    'Ethereum'),
                                CryptoCard(
                                    selectedCurrency,
                                    snapshot.connectionState ==
                                            ConnectionState.waiting
                                        ? '---'
                                        : coinData[2],
                                    'Litecoin'),
                              ],
                              onPressed: (int index) {
                                setState(() {
                                  for (int buttonIndex = 0;
                                      buttonIndex < isSelectedCrypto.length;
                                      buttonIndex++) {
                                    if (buttonIndex == index) {
                                      isSelectedCrypto[buttonIndex] = true;
                                      selectedCrypto =
                                          cryptoAbbreviation[buttonIndex];
                                      print("selectedCrypto");
                                      print(selectedCrypto);
                                    } else {
                                      isSelectedCrypto[buttonIndex] = false;
                                    }
                                  }
                                });

                                futureData = getData();
                              },
                              isSelected: isSelectedCrypto))

Answer 1

ToggleButton has a property selectedBorderColor which you can use to set the border color of your selected button. You can use a custom widget to give rounded border to each individual button.

Please see the code below :

import 'package:flutter/material.dart';

final Color darkBlue = const Color.fromARGB(255, 18, 32, 47);
void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key key, this.title}) : super(key: key);
  final String title;
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<bool> isSelected = List.generate(6, (index) => false);
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: ToggleButtons(
          children: [
            CustomIcon(
              icon: const Icon(Icons.ac_unit),
              isSelected: isSelected[0],
              bgColor: const Color(0xfff44336),
            ),
            CustomIcon(
              icon: const Icon(Icons.call),
              isSelected: isSelected[1],
              bgColor: const Color(0xffE91E63),
            ),
            CustomIcon(
              icon: const Icon(Icons.cake),
              isSelected: isSelected[2],
              bgColor: const Color(0xff9C27B0),
            ),
            CustomIcon(
              icon: const Icon(Icons.add),
              isSelected: isSelected[3],
              bgColor: const Color(0xff673AB7),
            ),
            CustomIcon(
              icon: const Icon(Icons.accessibility),
              isSelected: isSelected[4],
              bgColor: const Color(0xff3F51B5),
            ),
            CustomIcon(
              icon: const Icon(Icons.analytics),
              isSelected: isSelected[5],
              bgColor: const Color(0xff2196F3),
            ),
          ],
          onPressed: (int index) {
            setState(() {
              for (int buttonIndex = 0;
                  buttonIndex < isSelected.length;
                  buttonIndex++) {
                if (buttonIndex == index) {
                  isSelected[buttonIndex] = !isSelected[buttonIndex];
                } else {
                  isSelected[buttonIndex] = false;
                }
              }
            });
          },
          isSelected: isSelected,
          selectedColor: Colors.amber,
          renderBorder: false,
          fillColor: Colors.transparent,
        ),
      ),
    );
  }
}

class CustomIcon extends StatefulWidget {
  final Icon icon;
  final bool isSelected;
  final Color bgColor;

  const CustomIcon(
      {Key key,
      this.icon,
      this.isSelected = false,
      this.bgColor = Colors.green})
      : super(key: key);
  @override
  _CustomIconState createState() => _CustomIconState();
}

class _CustomIconState extends State<CustomIcon> {
  @override
  Widget build(BuildContext context) {
    return Container(
      width: 47,
      height: 47,
      decoration: BoxDecoration(
        border: widget.isSelected
            ? Border.all(
                color: const Color(0xffC5CAE9),
              )
            : null,
        borderRadius: const BorderRadius.all(
          Radius.circular(10),
        ),
      ),
      child: Center(
        child: Container(
          height: 32,
          width: 32,
          decoration: BoxDecoration(
            color: widget.bgColor,
            borderRadius: const BorderRadius.all(
              Radius.circular(5),
            ),
          ),
          child: widget.icon,
        ),
      ),
    );
  }
}