Flutter Flat Button Color Property Not Working

You need to provide child and onPressed parameter in order to render the widget, else it won't render, which results in non working UI.

Check out the code i modified :

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Center(
          child: MyWidget(),
        ),
      ),
    );
  }
}

class MyWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        home: SafeArea(
      child: Scaffold(
        body: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            FlatButton(
              color: Colors.red,
              onPressed:()=>printData(),
              child: Text("click"),
            ),
            FlatButton(
              color: Colors.green,
              onPressed:()=>printData(),
              child: Text("click"),
            ),
            FlatButton(
              color: Colors.blue,
              onPressed:()=>printData(),
              child: Text("click"),
            ),
          ],
        ),
      ),
    ));
  }
}

void printData(){
  print('Hello');
}

Have a look at the @required fields of the FlatButton Constructor without which it would not render.

This is a Flat button with required fields. Add your desired color to this to render it. Without a color it renders with black text and white background.

FlatButton(
  onPressed: () {
    /*...*/
  },
  child: Text(
    "Flat Button",
  ),
)

I was having same problem. I just added "disabledColor : Colors.red" Check screenshot.

enter image description here