Error while changing the flutter theme color to black

Question

My first steps in Flutter on Android Studio. My steps:

1. Download and install Android Studio
2. Download and install Flutter and Dart
3. Creating the first default app in flutter

This is the demo app:

In the commentary in the code of this app we have:

    // This is the theme of your application.
    // Try running your application with "flutter run". You'll see the
    // application has a blue toolbar. Then, without quitting the app, try
    // changing the primarySwatch below to Colors.green and then invoke
    // "hot reload"

I changed Colors.blue to Colors.green and the Hot Reload works fine the app changes to green. But when I try to change to Colors.black I have the error:

type 'Color' is not a subtype of type 'MaterialColor'.

The full code of the demo app:

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or press Run > Flutter Hot Reload in IntelliJ). Notice that the
        // counter didn't reset back to zero; the application is not restarted.
        primarySwatch: Colors.black,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return new Scaffold(
      appBar: new AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: new Text(widget.title),
      ),
      body: new Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: new Column(
          // Column is also layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug paint" (press "p" in the console where you ran
          // "flutter run", or select "Toggle Debug Paint" from the Flutter tool
          // window in IntelliJ) to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new Text(
              'You have pushed the button this many times:',
            ),
            new Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: new Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

Answer 1

theme: ThemeData(
    title: 'Flutter Demo',
    colorScheme: ThemeData().colorScheme.copyWith(
          primary: Colors.purple,
          secondary: Colors.deepOrange,
        ),
  ),

Answer 2

This is how I fixed it

class MainApp extends StatelessWidget {
  static Map<int, Color> color = {
    50: Color.fromRGBO(136, 14, 79, .1),
    100: Color.fromRGBO(136, 14, 79, .2),
    200: Color.fromRGBO(136, 14, 79, .3),
    300: Color.fromRGBO(136, 14, 79, .4),
    400: Color.fromRGBO(136, 14, 79, .5),
    500: Color.fromRGBO(136, 14, 79, .6),
    600: Color.fromRGBO(136, 14, 79, .7),
    700: Color.fromRGBO(136, 14, 79, .8),
    800: Color.fromRGBO(136, 14, 79, .9),
    900: Color.fromRGBO(136, 14, 79, 1),
  };
  MaterialColor primeColor = MaterialColor(0xFF337C36, color);
  MaterialColor accentColor = MaterialColor(0xFF337C36, color);
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primarySwatch: primeColor,
        accentColor: accentColor,
      ),
    );
  }
}

Answer 3

Also you cold simply use

theme: ThemeData.dark()

to change your applications theme to Dark

Answer 4

I'm sorry for that, but I feel the answer of @chemamolins answer should not be the accepted one.
And perhaps it's necessary to clarify some key points about colors, cause misunderstanding of these concepts can lead to bad design.

About Colors:

The fact of the matter is that black and white are not colors. See: https://adobe.com/creativecloud/design/discover/is-black-a-color.html

Physically, when your eyes see some white it's because the surface reflect an addition of all the colors of the spectrum.
And so you can't say white is "a color" cause it's "some colors".

On the other hand black is just what you see when no colors have been reflected.
And "no colors" means... "no colors" right ?

Back to Flutter:

The value of this color should the same the value of index 500 and shade500.

See: https://api.flutter.dev/flutter/material/MaterialColor-class.html

And so, for all the value above 500 (600...900) nothing exists because nothing can be darker than black.
That's why it's a non-sense to create a swatch for something like that.

The right Solution:

To my eyes, the cleaner solution has been proposed by @MacDonal_11

@override
Widget build(BuildContext context) {
  return MaterialApp(
    title: 'Flutter Demo',
    theme: ThemeData(
      //primarySwatch: Colors.blue,
      primaryColor: Colors.black,
      
      /**
       * ... [The rest of your config here] ...
       */
      
      visualDensity: VisualDensity.adaptivePlatformDensity,
    ),
    home: MyHomePage(title: 'Flutter Demo Home Page'),
  );
}

Answer 5

Just use primaryColor: Colors.black

I am not getting this whole primarySwatch cr#^...

Answer 6

I have used following code to get Black Color theme.

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(

        primaryColor: Colors.black,
        //primarySwatch: Colors.black,

      ),
      home: MyHomePage(title: 'Flutter First Home Page' ),
    );
  }
}

Color Code:

Inside Theme Data: (theme_data.dart)

........
......

brightness ??= Brightness.light;
final bool isDark = brightness == Brightness.dark;
primarySwatch ??= Colors.blue;
primaryColor ??= isDark ? Colors.grey[900] : primarySwatch;
primaryColorBrightness ??= estimateBrightnessForColor(primaryColor);
primaryColorLight ??= isDark ? Colors.grey[500] : primarySwatch[100];
primaryColorDark ??= isDark ? Colors.black : primarySwatch[700];
final bool primaryIsDark = primaryColorBrightness == Brightness.dark;
toggleableActiveColor ??= isDark ? Colors.tealAccent[200] : (accentColor ?? primarySwatch[600]);
accentColor ??= isDark ? Colors.tealAccent[200] : primarySwatch[500];
accentColorBrightness ??= estimateBrightnessForColor(accentColor);
final bool accentIsDark = accentColorBrightness == Brightness.dark;
canvasColor ??= isDark ? Colors.grey[850] : Colors.grey[50];
scaffoldBackgroundColor ??= canvasColor;
bottomAppBarColor ??= isDark ? Colors.grey[800] : Colors.white;
cardColor ??= isDark ? Colors.grey[800] : Colors.white;
dividerColor ??= isDark ? const Color(0x1FFFFFFF) : const Color(0x1F000000);
.....
.......

Output

Answer 7

You can't use Colors.black because it is not a MaterialColor and primarySwatch expects a material color palette.

If you go to the definition of ThemeData you will see the following:

  ///  * The primary color palette (the [primarySwatch]), chosen from
  ///    one of the swatches defined by the material design spec. This
  ///    should be one of the maps from the [Colors] class that do not
  ///    have "accent" in their name.

For instance, the definition of Colors.blue is:

  static const MaterialColor blue = MaterialColor(
    _bluePrimaryValue,
    <int, Color>{
       50: Color(0xFFE3F2FD),
      100: Color(0xFFBBDEFB),
      200: Color(0xFF90CAF9),
      300: Color(0xFF64B5F6),
      400: Color(0xFF42A5F5),
      500: Color(_bluePrimaryValue),
      600: Color(0xFF1E88E5),
      700: Color(0xFF1976D2),
      800: Color(0xFF1565C0),
      900: Color(0xFF0D47A1),
    },
  );
  static const int _bluePrimaryValue = 0xFF2196F3;

While the definition of Colors.black is:

static const Color black = Color(0xFF000000);

That is why you can't use black there. For the same reason you can't use Colors.white. Those two are the exceptions to the above explanation of using colors that doesn't have the accent word.

If you want black, you can create your own palette:

const MaterialColor primaryBlack = MaterialColor(
  _blackPrimaryValue,
  <int, Color>{
    50: Color(0xFF000000),
    100: Color(0xFF000000),
    200: Color(0xFF000000),
    300: Color(0xFF000000),
    400: Color(0xFF000000),
    500: Color(_blackPrimaryValue),
    600: Color(0xFF000000),
    700: Color(0xFF000000),
    800: Color(0xFF000000),
    900: Color(0xFF000000),
  },
);
const int _blackPrimaryValue = 0xFF000000;

And then use the primaryBlack instead of Colors.black.

You could adjust the different colors in the palette.