How to Make Random Color Generator In Flutter ?

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How to Make Random Color Generator In Flutter
How to Make Random Color Generator In Flutter

How to Make Random Color Generator In Flutter?

To make a Random Color Generator user can make use of an inbuilt Random class. User needs to make changes in the color when the button is pressed, you have to use a StatefulWidget. Code Snippet will look like the below:

import 'package:flutter/material.dart';
import 'dart:math';

void main() {
  runApp(
    MaterialApp(
      home: MyApp(),
    ),
  );
}

class MyApp extends StatefulWidget {
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {

  List colors = [Colors.red, Colors.green, Colors.yellow];
  Random random = new Random();

  int index = 0;

  void changeIndex() {
    setState(() => index = random.nextInt(3));
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: RaisedButton(
        onPressed: () => changeIndex(),
        child: Text('Click'),
        color: colors[index],
      ),
    );
  }
}

User can also try with below code snippet:

Random class is a generator of an int, bool, or double values.

Color((math.Random().nextDouble() * 0xFFFFFF).toInt()).withOpacity(1.0)

There is also an in-built list of available Colors. Users can also select a desire Color as per his or her end-user requirement. Consider a code snippet like the below:

Colors.primaries[Random().nextInt(Colors.primaries.length)]

Import a package like the below:

import 'dart:math';
Icon(
    Icons.account_circle,
    size: 40,
    color:   Colors.primaries[Random().nextInt(Colors.primaries.length)],
)
import 'dart:math';
import 'dart:ui';

class Util {
  static Color randomColor() {
    return Color(Random().nextInt(0xffffffff));
  }
}

For opaque color:

static Color randomOpaqueColor() {
  return Color(Random().nextInt(0xffffffff)).withAlpha(0xff);
}

There is also a different color for the button every time the build method for the app is called.

import 'package:flutter/material.dart';
   import 'dart:math';

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

   class MyApp extends StatelessWidget {
     @override
     Widget build(BuildContext context) {
     // TODO: implement build
       return new MaterialApp(
           title: "Raised Button",
           theme: new ThemeData(
              primarySwatch: Colors.teal,
           ),
           home: new HomePage());
     }
   }

   class HomePage extends StatefulWidget {
     @override
     HomePageState createState() => new HomePageState();
   }

   class HomePageState extends State<HomePage> {
     //contains the colours for the circle Avatars
     final List<Color> circleColors = [Colors.red, Colors.blue, Colors.green];

     Color randomGenerator() {
       return circleColors[new Random().nextInt(2)];
     }

     @override
     Widget build(BuildContext context) {
       return Center(
         child: RaisedButton(
           onPressed: () => {},
           child: Text('Click'),
           color: randomGenerator(),
         ),
       );
     }
 }

User can also try the below way:

import 'dart:math';
import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(home: MyPage()));
}

class MyPage extends StatefulWidget {
  @override
  _MyPageState createState() => new _MyPageState();
}

class _MyPageState extends State<MyPage> {
  final Random _random = Random();

  Color _color = Color(0xFFFFFFFF);

  void changeColor() {
    setState(() {
      _color = Color.fromARGB(
        //or with fromRGBO with fourth arg as _random.nextDouble(),
        _random.nextInt(256),
        _random.nextInt(256),
        _random.nextInt(256),
        _random.nextInt(256),
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: InkWell(
        onTap: changeColor,
        child: Container(
          color: _color,
        ),
      ),
    );
  }
}

If you use Color.fromRGBO:

The fourth argument should be within 0.0 to 1.0 and fortunately, we have _random.nextDouble() that gives a value between 0.0 to 1.0 randomly.

By the way:

  • R – Red
  • B – Blue
  • G – Green
  • O – Opacity
  • A – Alpha

User can also create a custom function like below:

import 'dart:math' as math;

final rnd = math.Random();

Color getRandomColor() => Color(rnd.nextInt(0xffffffff));

There is a random_color plugin in the Flutter that can help us for generating random color and also we can select high saturation colors with this code:

import 'package:random_color/random_color.dart';

RandomColor _randomColor = RandomColor();

Color _color = _randomColor.randomColor(
  colorSaturation: ColorSaturation.highSaturation
);

And light colors with this code:

import 'package:random_color/random_color.dart';

RandomColor _randomColor = RandomColor();

Color _color = _randomColor.randomColor(
  colorBrightness: ColorBrightness.light
);

Conclusion:

In this article, We have been through How to Make Random Color Generator In Flutter?

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