Skip to main content

Flutter Color Developer Guide

This guide will help you apply colors to your flutter apps using Flutter Material Colors Class and Flutter Dart-UI Color Class. You will also learn some basics about color channels, alpha channel, transparency etc.

flutter color developer guide

Flutter uses Flutter Material Colors Class and Flutter Dart-UI Color Class to paint colors on your app screen. 
  • Flutter Material - Colors Class
  • Flutter Dart-UI - Color Class
Flutter Colors Demo
Flutter Colors Demo

How to apply colors to my flutter app ? 

How to use Flutter Material Colors Class ?

Flutter Material Colors Class - Documentation
Also refer official class documentation with this guide to deeply understand the concept.
Let us start with the simplest way to apply colors to your flutter app widgets.

1. Colors class - Use Color using COLOR NAME (class constants) 

color :

Colors Class Constants
Colors Class Constants
Orange Container Widget UI
Orange Container Widget UI

2.Colors class - Use Color using COLOR NAME & COLOR SHADE

  • Color shade ranges from 100 to 900 in increment of one hundred
  • Color with shade 50 is also added to above range in some colors
  • Accent Colors have only shade values 100,200,400 and 700
  • Lower Shade Value - Pale Color
  • Higher Shade Value - Darker Color

Darker Orange Shade -[900]
Darker Orange Shade -[900]

How to use color shade value ?
Both of the above methods have same output[900][900]

Both the above methods have same output 

Color Shade Orange 900 UI
Color Shade Orange 900 UI

Note : is same as[500] or

3. Colors class - Black and White Colors

  • We have separate set of constants for color black and color white
  • These colors are identified by their transparency and not shade values.
  • Colors.black54 - pure black with 54 % opacity
  • Colors.black12 - pure black with 12 % opacity
  • Lower Number - Transparent Color
  • Higher Number - Opaque Color
White & Black Colors
White & Black Colors

Note : Transparent Color - Colors.transparent constant - entirely invisble

How to use Flutter Dart-UI Color Class ?

Flutter Dart-UI - Color Class - Documentation
Also refer official class documentation with this guide to deeply understand the concept.
Let us first understand the basics of colors.

Color channels

  1. Red Channel 
  2. Green Channel
  3. Blue Channel
  4. Alpha Channel (Transparency)

Color Class Properties

  • Alpha Property - Docs
    • Alpha Channel of this Color is in 8 bit value
    • 8 bit value mean range 0 to 255 (2 raise to 8 = 256)
    • 0 means this color is fully transparent
    • 255 means this color is fully opaque
    • return type int
Alpha Property Summary
8 bit value  - 0 (transparent) to 255 (opaque)
  • Opacity Property - Docs
    • Alpha channel of this color is in double value
    • double value mean ranges from 0.0 to 1.0 
    • 0.0 means this color is fully transparent
    • 1.0 means this color is fully opaque
    • return type double
Opacity Property Summary
double value - 0.0 (transparent) to 1.0 (opaque)
  • Value Property
Color represented as 32  bit value
Bits are assigned as follows :
  • Bits 0 to 7 Blue value (Blue Channel)
  • Bits 8 to 15 Green Value (Green Channel)
  • Bits 16 to 23 Red Value (Red Channel)
  • Bits 24 to 31 Alpha Value (Alpha Channel)
Difference between Alpha and Opacity
Alpha sets alpha channel value in 8 bit value and Opacity sets alpha channel value in double

Let us also understand what is 0xFFFFA726 ?

Orange Int Value
Orange Int Value

In the common "hash syntax" we represent color values as #FFA726 (Ignore 0xFF at the beginning).

Using a color picker tool, we get the same color ie.[400] using "hash syntax" #FFA726

If we convert hex code to decimal code, we can get the RGB values.

  • Red Channel FF (hex) equals 255 (decimal)
  • Green Channel A7 (hex) equals 167(decimal)
  • Blue Channel 26 (hex) equals  38(decimal)
Thus,  0xFFFFA726 is 0x FF(alpha) FF(red) A7(green) 26(blue)

Now, we have understood all the basics of color values and color channels we can now proceed with implementation code of the constructors of the Color class

Color Class Constructor

1. fromARGB Decimal (int) => Color.fromARGB(int a, int r, int g, int b)

color : Color.fromARGB (255,255,167,38) // fromARGB Decimal

ARGB int
ARGB int

2. fromARGB Hex 

Note : Add 0x to the value, for example, Green channel (hex) A7 will become 0xA7 
color : Color.fromARGB (0xFF,0xFF,0xA7,0x26) // fromARGB Hex


3. fromRGBO Decimal (int) => Color.fromRGBO(int r, int g, int b, double opacity)

color : Color.fromRGBO(255,167,38,1.0) // fromRGBO Decimal
  • O stands for opacity - refer above explained opacity property summary
  • double value - 0.0 (transparent) to 1.0 (opaque)

4. Color - Color(int value) - 0xAARRGGBB

  • Get any color int value for example #FFA726
  • Add 0xFF to "hash syntax" FFA726 => 0xFFFFA726
  • 0xFF added to hash syntax is the alpha channel FF(hex) => 255 (decimal) opaque color
color : Color(0xFFFFA726) // int value

Color Int Value
Color Int Value

Output UI Color for all above 4 constructor is same 

Color Constructor Output
Color Constructor Output

Coding - Sample Flutter App Code

To learn more about flutter - Flutter Developer Guide

Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited.The materials(images, logos, content) contained in this web site are protected by applicable copyright and trade mark law.

Flutter, Android, the Android logo, Google and the Google logo are registered trademarks of Google LLC.

Popular posts from this blog

Step-by-Step Guide to create a new flutter project using Visual Studio Code [VS Code]

This is a beginner's guide to visual studio code and flutter. VS Code is a light weight editor with flutter app development, execution and debug support. Visual Studio Code is a source-code editor developed by Microsoft. Install latest stable version of VS Code Install the Flutter and Dart plugins In VS Code "Extensions" Tab, search field type flutter, select "Flutter" in the list and click "Install". Flutter plugin also installs the required Dart plugin. Validate your flutter setup using "flutter doctor command". Once Flutter SDK and your VS Code Editor is up and running, Flutter Visual Studio Code To Create a new flutter project from the flutter starter app template follow the below steps step 1 : Open Command Palette Use Shortcut key - Ctrl+Shift+P or Cmd+Shift+P on macOS OR Go to View Menu, select "Command Palette" VS Code Command Palette step 2 : Create Flutter New Project Sele

Step-by-Step Guide for Flutter Android APK Signing and Release

In this guide we will learn how to sign the release version of apk or aab(android app bundle) to publish our flutter app to android play store. flutter release apk How to sign the apk or app bundle created using flutter ? To publish your app on Play Store, you need to give your app a digital signature. step 1 : Create a new keystore file ; if you have an existing keystore , skip this step Run command in your terminal for linux/mac keytool -genkey -v -keystore ~/key.jks -keyalg RSA -keysize 2048 -validity 10000 -alias key On Windows, use the following command: keytool -genkey -v -keystore c:/Users/USER_NAME/key.jks -storetype JKS -keyalg RSA -keysize 2048 -validity 10000 -alias key Fill in the required info inside the terminal Enter keystore password: test@12345 Re-enter new password: test@12345 What is your first and last name? [test]: test What is the name of your organizational unit? [test]: test

Step-by-Step Guide to take a App Screenshot with the Device Frame using Android Studio

This guide will help you to take a screenshot with the device frame using android studio. If we capture screenshot using the default android emulator "Capture Screenshot" option, then screenshot will not have the device frame. Android Emulator - Screen Capture By using android studio we can capture screenshot with different devices frame. How to take a App Screenshot with the Device Frame using Android Studio step 1 : Load your project in android studio and run the app Open Android Studio Load your android app project in android studio.  Build and Run your app using android emulator or a connected physical device.  If you are using a physical device make sure that you have enabled USB DEBUGGING option. Android Studio - Load Project step 2 : Open Logcat in Android Studio Check out bottom left corner in android studio to find Logcat option and click to open Logcat If it is not visible then select "View Menu" and search for