import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData.dark(),
      home: Scaffold(
        body: DropdownButtonHideUnderline(
          child: DropdownButtonFormField<Color>(
            selectedItemBuilder: (context) {
              return [
                DropdownMenuItem<Color>(
                  value: Colors.green,
                  child: RichText(
                    text: TextSpan(
                      children: [
                        WidgetSpan(
                          child: Padding(
                            padding: const EdgeInsets.only(
                              right: 10,
                            ),
                            child: Icon(Icons.ac_unit),
                          ),
                          baseline: TextBaseline.alphabetic,
                          alignment: PlaceholderAlignment.aboveBaseline,
                        ),
                        const TextSpan(text: 'By '),
                        TextSpan(
                          text: 'test',
                          style: const TextStyle(
                            fontWeight: FontWeight.w700,
                          ),
                        ),
                      ],
                    ),
                  ),
                )
              ];
            },
            icon: SizedBox(),
            value: Colors.accents[1],
            decoration: const InputDecoration(
              enabledBorder: UnderlineInputBorder(
                borderSide: BorderSide(
                  color: Colors.transparent,
                ),
              ),
              focusedBorder: UnderlineInputBorder(
                borderSide: BorderSide(
                  color: Colors.transparent,
                ),
              ),
              labelStyle: TextStyle(
                color: Colors.black,
                fontWeight: FontWeight.w500,
                fontSize: 14,
              ),
            ),
            items: Colors.accents.map((value) {
              return DropdownMenuItem<Color>(
                value: value,
                child: RichText(
                  text: TextSpan(
                    children: [
                      TextSpan(
                        text: value.toString(),
                        style: const TextStyle(
                          fontWeight: FontWeight.w700,
                        ),
                      ),
                    ],
                  ),
                ),
              );
            }).toList(),
            onChanged: (value) {},
          ),
        ),
      ),
    ),
  );
}