change flutter theme dynamically using getx library
change flutter theme dynamically using getx library

Hi Guys, Welcome to Proto Coders Point, In this Flutter Tutorial we will create a app where user can select his desired theme either dark theme in flutter or light theme in flutter.

VIDEO TUTORIAL

Flutter Dynamic theme change using getX

Step 1 : Create a new Flutter project

Start your favorite IDE, In my case i am making user of ANDROID STUDIO to build Flutter project, you may use as per your choice.

Create a new Flutter project
IDE -> Files -> New > New Flutter Project -> give name -> give package name and finish

Step 2: Add GetX & Get Storage dependencies

Then, once your flutter project is been created, you need to add 2 required dependencies i.e. GetX  & Get Storage in pubspec.yaml

adding depencencies in flutter getx get storage
adding depencencies in flutter getx get storage

Step 3 : Adding images in Flutter project

create a package/folder in your flutter project structure, Right click on project -> New -> Directory (give name) and add image files in that folder.

After creating the directory you need to specify the path of the directory you have created in pubspec.yaml file so that your flutter project can access the images.

You can see in below screenshot, i have created folder by name images which has 2 images in it, and then in pubspec.yaml file i have gave the image path in flutter.

flutter image, assets path

Step 4: The Code

If you face problem in understand below code, learn basic of Getx and Get Storage (link is below)

void main() async{
  await GetStorage.init();  // before building the app  you need to initialize GetStorage  // so that we have access to use app data
  runApp(MyApp());
}

Then, Create a instance of GetStorage class

final appdata = GetStorage();  // instance of GetStorage

Now, using instance create a key-value pair

appdata.writeIfNull('darkmode', false);

as you see above, ‘darkmode’ is a key and false is value stored in it.

bool isDarkMode = appdata.read('darkmode');  //  get data from get storage and store in a boolean variable

This isDarkMode will store either true or false, If true then it means, user have previously turned on dark mode before closing the app.

and depending on isDarkMode, we will set the theme of the app either dark mode or light mode.

A Switch Widget to turn on/off dark mode dynamically in flutter

Switch(
                    value: isDarkMode ,
                    onChanged: (value) => appdata.write('darkmode', value),
      )

Complete Flutter code main.dart

This complete code will be posted on github repository, you may download it from there (link below)

import 'package:flutter/material.dart';
import 'package:get_storage/get_storage.dart';
import 'package:get/get.dart';

void main() async{
  await GetStorage.init();  // before building the app  you need to initialize GetStorage
  runApp(MyApp());
}

class MyApp extends StatelessWidget {

  final appdata = GetStorage();  // instance of GetStorage

  @override
  Widget build(BuildContext context) {

    appdata.writeIfNull('darkmode', false);
    return SimpleBuilder(
      builder: (_)
      {
        bool isDarkMode = appdata.read('darkmode');
        return GetMaterialApp(
          theme: isDarkMode ? ThemeData.dark() : ThemeData.light(),
          home: Scaffold(
            appBar: AppBar(title: Text("Getx Dynamic theme change"),),
            body: Center(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Image.asset(isDarkMode ? 'images/night.png' :'images/day.png' ,width: 100,height: 100,),
                  Switch(
                    value: isDarkMode ,
                    onChanged: (value) => appdata.write('darkmode', value),
                  )
                ],
              ),
            ),
          ),
        );
      },
    );
  }
}

To make it easy i am making user of Getx & Get Storage package https://pub.dev/packages/get_storage/

Watch this video to learn basic of Get Storage and Getx Basic : https://www.youtube.com/watch?v=L7Zs4yuStsw&t=1s

Keep user logged in into the app :

https://youtu.be/ViXfhl4dA3w

clone project on github https://github.com/RajatPalankar8/flutter_dynamic_theme_change.git

Comment below for any queries

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