如何在 Flutter 中使我的单选按钮完全填充有活动颜色的颜色而没有白色边框？

Question

I want to fully fill my radio button with a single color. Like this

Currently Radio button give this layout by default.

So how can I change this?

My Code

Radio(
                    value: 3,
                    groupValue: radioValue,
                    onChanged: onChanged,
                    fillColor: MaterialStateColor.resolveWith(
                        (states) => Colors.lightBlueAccent),
                  ),

Please Help

Answer 1

You can create your own radio widget to achieve this:

class FilledRadio<T> extends StatelessWidget {
  final T value;
  final T groupValue;
  final ValueChanged<T> onChanged;
  final double radius;
  final Color color;

  FilledRadio(
      {required this.value,
      required this.groupValue,
      required this.onChanged,
      this.radius = 16,
      this.color = const Color(0xFF49EF3E)});

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(8.0),
      child: GestureDetector(
        onTap: () {
          onChanged(this.value);
        },
        child: Container(
          height: this.radius * 2,
          width: this.radius * 2,
          decoration: ShapeDecoration(
            shape: CircleBorder(),
            color: color,
          ),
          child: Center(
            child: Container(
              height: (this.radius * 2) - 8,
              width: (this.radius * 2) - 8,
              decoration: ShapeDecoration(
                shape: CircleBorder(),
                color: value == groupValue
                    ? color
                    : Theme.of(context).scaffoldBackgroundColor,
              ),
            ),
          ),
        ),
      ),
    );
  }
}

You can use it like:

Row(
   mainAxisAlignment: MainAxisAlignment.center,
   children: <Widget>[
      FilledRadio(
        value: "0",
        radius: 20,
        color: Colors.redAccent,
        groupValue: _radValue,
        onChanged: (String value) {
          setState(() {
            _radValue = value;
          });
        },
      ),
      FilledRadio(
        value: "1",
        radius: 16,
        color: Colors.red,
        groupValue: _radValue,
        onChanged: (String value) {
          setState(() {
            _radValue = value;
          });
        },
      ),
      FilledRadio(
        value: "2",
        radius: 12,
        color: Colors.amber,
        groupValue: _radValue,
        onChanged: (String value) {
          setState(() {
            _radValue = value;
          });
        },
      ),
      FilledRadio(
        value: "3",
        radius: 16,
        color: Colors.green,
        groupValue: _radValue,
        onChanged: (String value) {
          setState(() {
            _radValue = value;
          });
        },
      ),
      FilledRadio(
        value: "4",
        radius: 20,
        color: Colors.greenAccent,
        groupValue: _radValue,
        onChanged: (String value) {
          setState(() {
            _radValue = value;
          });
        },
      ),
   ],
),

And it will look like:

Note: This implementation supports only from dart 2.12.0 and above. If you are trying to use it in older versions of dart, just change the constructor to:

FilledRadio(
      {@required this.value,
      @required this.groupValue,
      @required this.onChanged,
      this.radius = 16,
      this.color = const Color(0xFF49EF3E)});