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Get সম্পর্কে

  • GetX হল ফ্লটারের জন্য একটি লাইটওয়েট এবং শক্তিশালী সমাধান। এটি দ্রুত এবং ব্যবহারিকভাবে উচ্চ-পারফরম্যান্স স্টেট ব্যবস্থাপনা, বুদ্ধিমান ডিপেনডেন্সি ইনজেকশন এবং রুট ব্যবস্থাপনাকে একত্রিত করে।

  • GetX এর ৩টি মৌলিক নীতি রয়েছে: উৎপাদনশীলতা, কর্মক্ষমতা এবং সংগঠন। এর মানে হল যে এইগুলি লাইব্রেরির সমস্ত রিসোর্স এর জন্য অগ্রাধিকার।

    • কর্মক্ষমতা: GetX কর্মক্ষমতা এবং রিসোর্স এর ন্যূনতম ব্যবহারের উপর ফোকাস করে। এটি স্ট্রিম বা চেঞ্জনোটিফায়ার ব্যবহার করে না।
    • উৎপাদনশীলতা: GetX একটি সহজ এবং মনোরম সিনট্যাক্স ব্যবহার করে। আপনি যা করতে চান না কেন, Getx এর সাথে সর্বদা একটি সহজ উপায় রয়েছে। এটি ডেভেলপমেন্ট এর সময় সাশ্রয় করবে এবং এটি আপনার অ্যাপ্লিকেশনটি সরবরাহ করতে পারে এমন সর্বাধিক কর্মক্ষমতা সরবরাহ করবে।
    • সংগঠন: GetX ভিউ, প্রেজেন্টেশন লজিক, বিজনেস লজিক, ডিপেন্ডেন্সি ইনজেকশন এবং নেভিগেশনের মোট ডিকপলিং করার অনুমতি দেয়। রুটগুলির মধ্যে নেভিগেট করার জন্য আপনার কনটেক্সট (context) প্রয়োজন নেই, তাই আপনাকে এর জন্য উইজেট ট্রি (ভিজ্যুয়ালাইজেশন) এর উপর নির্ভরশীল হতে হবে না।

  • GetX এর একটি বিশাল ইকো সিস্টেম, একটি বৃহত সম্প্রদায়, প্রচুর সংখ্যক সহযোগী রয়েছে এবং যতক্ষণ ফ্লাটার বিদ্যমান থাকবে ততক্ষণ রক্ষণাবেক্ষণ করা হবে। গেটএক্স অ্যান্ড্রয়েড, আইওএস, ওয়েব, ম্যাক, লিনাক্স, উইন্ডোজ এবং আপনার সার্ভারে একই কোড দিয়ে চলতে সক্ষম। গেট সার্ভার (Get Server) দিয়ে আপনার ফ্রন্টএন্ডে তৈরি কোডটি পুনরায় সম্পূর্ণরূপে ব্যাকএন্ডে ব্যবহার করা সম্ভব।

এছাড়াও সম্পূর্ণ ডেভেলপমেন্ট প্রক্রিয়া সার্ভারে এবং ফ্রন্টএন্ডে Get CLI এর মাধ্যমে স্বয়ংক্রিয়ভাবে করা যেতে পারে।.

এছাড়াও আপনার উত্পাদনশীলতা আরও বাড়াতে, আমাদের রয়েছে extension to VSCode এবং extension to Android Studio/Intellij

ইনস্টল

আপনার pubspec.yaml ফাইলে get যোগ করুন:

dependencies:
  get:

যে ফাইল এ ব্যবহার করবেন সেখানে ইম্পোর্ট করুন:

import 'package:get/get.dart';

GetX দিয়ে কাউন্টার অ্যাপ

The "counter" project created by default on new project on Flutter has over 100 lines (with comments). To show the power of Get, I will demonstrate how to make a "counter" changing the state with each click, switching between pages and sharing the state between screens, all in an organized way, separating the business logic from the view, in ONLY 26 LINES CODE INCLUDING COMMENTS.

  • Step 1: Add "Get" before your MaterialApp, turning it into GetMaterialApp
void main() => runApp(GetMaterialApp(home: Home()));
  • Note: this does not modify the MaterialApp of the Flutter, GetMaterialApp is not a modified MaterialApp, it is just a pre-configured Widget, which has the default MaterialApp as a child. You can configure this manually, but it is definitely not necessary. GetMaterialApp will create routes, inject them, inject translations, inject everything you need for route navigation. If you use Get only for state management or dependency management, it is not necessary to use GetMaterialApp. GetMaterialApp is necessary for routes, snackbars, internationalization, bottomSheets, dialogs, and high-level apis related to routes and absence of context.

  • Note²: This step is only necessary if you gonna use route management (Get.to(), Get.back() and so on). If you not gonna use it then it is not necessary to do step 1

  • Step 2: Create your business logic class and place all variables, methods and controllers inside it. You can make any variable observable using a simple ".obs".

class Controller extends GetxController{
  var count = 0.obs;
  increment() => count++;
}
  • Step 3: Create your View, use StatelessWidget and save some RAM, with Get you may no longer need to use StatefulWidget.
class Home extends StatelessWidget {

  @override
  Widget build(context) {

    // Instantiate your class using Get.put() to make it available for all "child" routes there.
    final Controller c = Get.put(Controller());

    return Scaffold(
      // Use Obx(()=> to update Text() whenever count is changed.
      appBar: AppBar(title: Obx(() => Text("Clicks: ${c.count}"))),

      // Replace the 8 lines Navigator.push by a simple Get.to(). You don't need context
      body: Center(child: ElevatedButton(
              child: Text("Go to Other"), onPressed: () => Get.to(Other()))),
      floatingActionButton:
          FloatingActionButton(child: Icon(Icons.add), onPressed: c.increment));
  }
}

class Other extends StatelessWidget {
  // You can ask Get to find a Controller that is being used by another page and redirect you to it.
  final Controller c = Get.find();

  @override
  Widget build(context){
     // Access the updated count variable
     return Scaffold(body: Center(child: Text("${c.count}")));
  }
}

Result:

This is a simple project but it already makes clear how powerful Get is. As your project grows, this difference will become more significant.

Get was designed to work with teams, but it makes the job of an individual developer simple.

Improve your deadlines, deliver everything on time without losing performance. Get is not for everyone, but if you identified with that phrase, Get is for you!

GetX এর তিনটি স্তম্ভ

স্টেট ব্যবস্থাপনা

Get has two different state managers: the simple state manager (we'll call it GetBuilder) and the reactive state manager (GetX/Obx)

প্রতিক্রিয়াশীল স্টেট ম্যানেজার

Reactive programming can alienate many people because it is said to be complicated. GetX turns reactive programming into something quite simple:

  • You won't need to create StreamControllers.
  • You won't need to create a StreamBuilder for each variable
  • You will not need to create a class for each state.
  • You will not need to create a get for an initial value.
  • You will not need to use code generators

Reactive programming with Get is as easy as using setState.

Let's imagine that you have a name variable and want that every time you change it, all widgets that use it are automatically changed.

This is your count variable:

var name = 'Ashiqur Rahman Alif';

To make it observable, you just need to add ".obs" to the end of it:

var name = 'Ashiqur Rahman Alif'.obs;

And in the UI, when you want to show that value and update the screen whenever the values changes, simply do this:

Obx(() => Text("${controller.name}"));

That's all. It's that simple.

স্টেট ব্যবস্থাপনা সম্পর্কে আরো বিস্তারিত

See an more in-depth explanation of state management here. There you will see more examples and also the difference between the simple state manager and the reactive state manager

You will get a good idea of GetX power.

রুট ব্যবস্থাপনা

If you are going to use routes/snackbars/dialogs/bottomsheets without context, GetX is excellent for you too, just see it:

Add "Get" before your MaterialApp, turning it into GetMaterialApp

GetMaterialApp( // Before: MaterialApp(
  home: MyHome(),
)

Navigate to a new screen:


Get.to(NextScreen());

Navigate to new screen with name. See more details on named routes here


Get.toNamed('/details');

To close snackbars, dialogs, bottomsheets, or anything you would normally close with Navigator.pop(context);

Get.back();

To go to the next screen and no option to go back to the previous screen (for use in SplashScreens, login screens, etc.)

Get.off(NextScreen());

To go to the next screen and cancel all previous routes (useful in shopping carts, polls, and tests)

Get.offAll(NextScreen());

Noticed that you didn't have to use context to do any of these things? That's one of the biggest advantages of using Get route management. With this, you can execute all these methods from within your controller class, without worries.

রুট ব্যবস্থাপনা সম্পর্কে আরো বিস্তারিত

Get works with named routes and also offers lower-level control over your routes! There is in-depth documentation here

ডিপেনডেন্সি ব্যবস্থাপনা

Get has a simple and powerful dependency manager that allows you to retrieve the same class as your Bloc or Controller with just 1 lines of code, no Provider context, no inheritedWidget:

Controller controller = Get.put(Controller()); // Rather Controller controller = Controller();
  • Note: If you are using Get's State Manager, pay more attention to the bindings API, which will make it easier to connect your view to your controller.

Instead of instantiating your class within the class you are using, you are instantiating it within the Get instance, which will make it available throughout your App. So you can use your controller (or class Bloc) normally

Tip: Get dependency management is decoupled from other parts of the package, so if for example, your app is already using a state manager (any one, it doesn't matter), you don't need to rewrite it all, you can use this dependency injection with no problems at all

controller.fetchApi();

Imagine that you have navigated through numerous routes, and you need data that was left behind in your controller, you would need a state manager combined with the Provider or Get_it, correct? Not with Get. You just need to ask Get to "find" for your controller, you don't need any additional dependencies:

Controller controller = Get.find();
//Yes, it looks like Magic, Get will find your controller, and will deliver it to you. You can have 1 million controllers instantiated, Get will always give you the right controller.

And then you will be able to recover your controller data that was obtained back there:

Text(controller.textFromApi);

ডিপেনডেন্সি ব্যবস্থাপনা সম্পর্কে আরো বিস্তারিত

See a more in-depth explanation of dependency management here

ইউটিলিটি

আন্তর্জাতিকীকরণ

অনুবাদ

Translations are kept as a simple key-value dictionary map. To add custom translations, create a class and extend Translations.

import 'package:get/get.dart';

class Messages extends Translations {
  @override
  Map<String, Map<String, String>> get keys => {
        'en_US': {
          'hello': 'Hello World',
        },
        'de_DE': {
          'hello': 'Hallo Welt',
        }
      };
}

অনুবাদের ব্যবহার

Just append .tr to the specified key and it will be translated, using the current value of Get.locale and Get.fallbackLocale.

Text('title'.tr);

Using translation with singular and plural

var products = [];
Text('singularKey'.trPlural('pluralKey', products.length, Args));

Using translation with parameters

import 'package:get/get.dart';


Map<String, Map<String, String>> get keys => {
    'en_US': {
        'logged_in': 'logged in as @name with email @email',
    },
    'es_ES': {
       'logged_in': 'iniciado sesión como @name con e-mail @email',
    }
};

Text('logged_in'.trParams({
  'name': 'Jhon',
  'email': 'jhon@example.com'
  }));

লোকেল

Pass parameters to GetMaterialApp to define the locale and translations.

return GetMaterialApp(
    translations: Messages(), // your translations
    locale: Locale('en', 'US'), // translations will be displayed in that locale
    fallbackLocale: Locale('en', 'UK'), // specify the fallback locale in case an invalid locale is selected.
);

লোকেল পরিবর্তন করুন

Call Get.updateLocale(locale) to update the locale. Translations then automatically use the new locale.

var locale = Locale('en', 'US');
Get.updateLocale(locale);

লোকেল পদ্ধতি

To read the system locale, you could use Get.deviceLocale.

return GetMaterialApp(
    locale: Get.deviceLocale,
);

থিম পরিবর্তন করুন

Please do not use any higher level widget than GetMaterialApp in order to update it. This can trigger duplicate keys. A lot of people are used to the prehistoric approach of creating a "ThemeProvider" widget just to change the theme of your app, and this is definitely NOT necessary with GetX™.

You can create your custom theme and simply add it within Get.changeTheme without any boilerplate for that:

Get.changeTheme(ThemeData.light());

If you want to create something like a button that changes the Theme in onTap, you can combine two GetX™ APIs for that:

  • The api that checks if the dark Theme is being used.
  • And the Theme Change API, you can just put this within an onPressed:
Get.changeTheme(Get.isDarkMode? ThemeData.light(): ThemeData.dark());

When .darkmode is activated, it will switch to the light theme, and when the light theme becomes active, it will change to dark theme.

গেট কানেক্ট (GetConnect)

GetConnect is an easy way to communicate from your back to your front with http or websockets

ডিফল্ট কনফিগারেশন

You can simply extend GetConnect and use the GET/POST/PUT/DELETE/SOCKET methods to communicate with your Rest API or websockets.

class UserProvider extends GetConnect {
  // Get request
  Future<Response> getUser(int id) => get('http://youapi/users/$id');
  // Post request
  Future<Response> postUser(Map data) => post('http://youapi/users', body: data);
  // Post request with File
  Future<Response<CasesModel>> postCases(List<int> image) {
    final form = FormData({
      'file': MultipartFile(image, filename: 'avatar.png'),
      'otherFile': MultipartFile(image, filename: 'cover.png'),
    });
    return post('http://youapi/users/upload', form);
  }

  GetSocket userMessages() {
    return socket('https://yourapi/users/socket');
  }
}

কাস্টম কনফিগারেশন

GetConnect is highly customizable You can define base Url, as answer modifiers, as Requests modifiers, define an authenticator, and even the number of attempts in which it will try to authenticate itself, in addition to giving the possibility to define a standard decoder that will transform all your requests into your Models without any additional configuration.

class HomeProvider extends GetConnect {
  @override
  void onInit() {
    // All request will pass to jsonEncode so CasesModel.fromJson()
    httpClient.defaultDecoder = CasesModel.fromJson;
    httpClient.baseUrl = 'https://api.covid19api.com';
    // baseUrl = 'https://api.covid19api.com'; // It define baseUrl to
    // Http and websockets if used with no [httpClient] instance

    // It's will attach 'apikey' property on header from all requests
    httpClient.addRequestModifier((request) {
      request.headers['apikey'] = '12345678';
      return request;
    });

    // Even if the server sends data from the country "Brazil",
    // it will never be displayed to users, because you remove
    // that data from the response, even before the response is delivered
    httpClient.addResponseModifier<CasesModel>((request, response) {
      CasesModel model = response.body;
      if (model.countries.contains('Brazil')) {
        model.countries.remove('Brazilll');
      }
    });

    httpClient.addAuthenticator((request) async {
      final response = await get("http://yourapi/token");
      final token = response.body['token'];
      // Set the header
      request.headers['Authorization'] = "$token";
      return request;
    });

    //Autenticator will be called 3 times if HttpStatus is
    //HttpStatus.unauthorized
    httpClient.maxAuthRetries = 3;
  }

  @override
  Future<Response<CasesModel>> getCases(String path) => get(path);
}

গেট পেজ মিডিলওয়্যার

The GetPage has now new property that takes a list of GetMiddleWare and run them in the specific order.

Note: When GetPage has a Middlewares, all the children of this page will have the same middlewares automatically.

অগ্রাধিকার (Priority)

The Order of the Middlewares to run can be set by the priority in the GetMiddleware.

final middlewares = [
  GetMiddleware(priority: 2),
  GetMiddleware(priority: 5),
  GetMiddleware(priority: 4),
  GetMiddleware(priority: -8),
];

those middlewares will be run in this order -8 => 2 => 4 => 5

পুনঃনির্দেশ (Redirect)

This function will be called when the page of the called route is being searched for. It takes RouteSettings as a result to redirect to. Or give it null and there will be no redirecting.

RouteSettings redirect(String route) {
  final authService = Get.find<AuthService>();
  return authService.authed.value ? null : RouteSettings(name: '/login')
}

অন-পেজ কলড (onPageCalled)

This function will be called when this Page is called before anything created you can use it to change something about the page or give it new page

GetPage onPageCalled(GetPage page) {
  final authService = Get.find<AuthService>();
  return page.copyWith(title: 'Welcome ${authService.UserName}');
}

অন-বাইন্ডিং স্টার্ট (OnBindingsStart)

This function will be called right before the Bindings are initialize. Here you can change Bindings for this page.

List<Bindings> onBindingsStart(List<Bindings> bindings) {
  final authService = Get.find<AuthService>();
  if (authService.isAdmin) {
    bindings.add(AdminBinding());
  }
  return bindings;
}

অন-পেজ বিল্ড স্টার্ট (OnPageBuildStart)

This function will be called right after the Bindings are initialize. Here you can do something after that you created the bindings and before creating the page widget.

GetPageBuilder onPageBuildStart(GetPageBuilder page) {
  print('bindings are ready');
  return page;
}

অন-পেজ বিল্ড (OnPageBuilt)

This function will be called right after the GetPage.page function is called and will give you the result of the function. and take the widget that will be showed.

অন-পেজ ডিসপোজ (OnPageDispose)

This function will be called right after disposing all the related objects (Controllers, views, ...) of the page.

অন্যান্য এপিআই সমূহ

// give the current args from currentScreen
Get.arguments

// give name of previous route
Get.previousRoute

// give the raw route to access for example, rawRoute.isFirst()
Get.rawRoute

// give access to Routing API from GetObserver
Get.routing

// check if snackbar is open
Get.isSnackbarOpen

// check if dialog is open
Get.isDialogOpen

// check if bottomsheet is open
Get.isBottomSheetOpen

// remove one route.
Get.removeRoute()

// back repeatedly until the predicate returns true.
Get.until()

// go to next route and remove all the previous routes until the predicate returns true.
Get.offUntil()

// go to next named route and remove all the previous routes until the predicate returns true.
Get.offNamedUntil()

//Check in what platform the app is running
GetPlatform.isAndroid
GetPlatform.isIOS
GetPlatform.isMacOS
GetPlatform.isWindows
GetPlatform.isLinux
GetPlatform.isFuchsia

//Check the device type
GetPlatform.isMobile
GetPlatform.isDesktop
//All platforms are supported independently in web!
//You can tell if you are running inside a browser
//on Windows, iOS, OSX, Android, etc.
GetPlatform.isWeb


// Equivalent to : MediaQuery.of(context).size.height,
// but immutable.
Get.height
Get.width

// Gives the current context of the Navigator.
Get.context

// Gives the context of the snackbar/dialog/bottomsheet in the foreground, anywhere in your code.
Get.contextOverlay

// Note: the following methods are extensions on context. Since you
// have access to context in any place of your UI, you can use it anywhere in the UI code

// If you need a changeable height/width (like Desktop or browser windows that can be scaled) you will need to use context.
context.width
context.height

// Gives you the power to define half the screen, a third of it and so on.
// Useful for responsive applications.
// param dividedBy (double) optional - default: 1
// param reducedBy (double) optional - default: 0
context.heightTransformer()
context.widthTransformer()

/// Similar to MediaQuery.of(context).size
context.mediaQuerySize()

/// Similar to MediaQuery.of(context).padding
context.mediaQueryPadding()

/// Similar to MediaQuery.of(context).viewPadding
context.mediaQueryViewPadding()

/// Similar to MediaQuery.of(context).viewInsets;
context.mediaQueryViewInsets()

/// Similar to MediaQuery.of(context).orientation;
context.orientation()

/// Check if device is on landscape mode
context.isLandscape()

/// Check if device is on portrait mode
context.isPortrait()

/// Similar to MediaQuery.of(context).devicePixelRatio;
context.devicePixelRatio()

/// Similar to MediaQuery.of(context).textScaleFactor;
context.textScaleFactor()

/// Get the shortestSide from screen
context.mediaQueryShortestSide()

/// True if width be larger than 800
context.showNavbar()

/// True if the shortestSide is smaller than 600p
context.isPhone()

/// True if the shortestSide is largest than 600p
context.isSmallTablet()

/// True if the shortestSide is largest than 720p
context.isLargeTablet()

/// True if the current device is Tablet
context.isTablet()

/// Returns a value<T> according to the screen size
/// can give value for:
/// watch: if the shortestSide is smaller than 300
/// mobile: if the shortestSide is smaller than 600
/// tablet: if the shortestSide is smaller than 1200
/// desktop: if width is largest than 1200
context.responsiveValue<T>()

ঐচ্ছিক গ্লোবাল সেটিংস এবং ম্যানুয়াল কনফিগারেশন

GetMaterialApp configures everything for you, but if you want to configure Get manually.

MaterialApp(
  navigatorKey: Get.key,
  navigatorObservers: [GetObserver()],
);

You will also be able to use your own Middleware within GetObserver, this will not influence anything.

MaterialApp(
  navigatorKey: Get.key,
  navigatorObservers: [
    GetObserver(MiddleWare.observer) // Here
  ],
);

You can create Global Settings for Get. Just add Get.config to your code before pushing any route. Or do it directly in your GetMaterialApp

GetMaterialApp(
  enableLog: true,
  defaultTransition: Transition.fade,
  opaqueRoute: Get.isOpaqueRouteDefault,
  popGesture: Get.isPopGestureEnable,
  transitionDuration: Get.defaultDurationTransition,
  defaultGlobalState: Get.defaultGlobalState,
);

Get.config(
  enableLog = true,
  defaultPopGesture = true,
  defaultTransition = Transitions.cupertino
)

You can optionally redirect all the logging messages from Get. If you want to use your own, favourite logging package, and want to capture the logs there:

GetMaterialApp(
  enableLog: true,
  logWriterCallback: localLogWriter,
);

void localLogWriter(String text, {bool isError = false}) {
  // pass the message to your favourite logging package here
  // please note that even if enableLog: false log messages will be pushed in this callback
  // you get check the flag if you want through GetConfig.isLogEnable
}

লোকাল স্টেট উইজেট

These Widgets allows you to manage a single value, and keep the state ephemeral and locally. We have flavours for Reactive and Simple. For instance, you might use them to toggle obscureText in a TextField, maybe create a custom Expandable Panel, or maybe modify the current index in BottomNavigationBar while changing the content of the body in a Scaffold.

ভ্যালু বিল্ডার (ValueBuilder)

A simplification of StatefulWidget that works with a .setState callback that takes the updated value.

ValueBuilder<bool>(
  initialValue: false,
  builder: (value, updateFn) => Switch(
    value: value,
    onChanged: updateFn, // same signature! you could use ( newValue ) => updateFn( newValue )
  ),
  // if you need to call something outside the builder method.
  onUpdate: (value) => print("Value updated: $value"),
  onDispose: () => print("Widget unmounted"),
),

অবএক্সভ্যালু (ObxValue)

Similar to ValueBuilder, but this is the Reactive version, you pass a Rx instance (remember the magical .obs?) and updates automatically... isn't it awesome?

ObxValue((data) => Switch(
        value: data.value,
        onChanged: data, // Rx has a _callable_ function! You could use (flag) => data.value = flag,
    ),
    false.obs,
),

প্রয়োজনীয় পরামর্শ

.observables (also known as Rx Types) have a wide variety of internal methods and operators.

Is very common to believe that a property with .obs IS the actual value... but make no mistake! We avoid the Type declaration of the variable, because Dart's compiler is smart enough, and the code looks cleaner, but:

var message = 'Hello world'.obs;
print( 'Message "$message" has Type ${message.runtimeType}');

Even if message prints the actual String value, the Type is RxString!

So, you can't do message.substring( 0, 4 ). You have to access the real value inside the observable: The most "used way" is .value, but, did you know that you can also use...

final name = 'GetX'.obs;
// only "updates" the stream, if the value is different from the current one.
name.value = 'Hey';

// All Rx properties are "callable" and returns the new value.
// but this approach does not accepts `null`, the UI will not rebuild.
name('Hello');

// is like a getter, prints 'Hello'.
name() ;

/// numbers:

final count = 0.obs;

// You can use all non mutable operations from num primitives!
count + 1;

// Watch out! this is only valid if `count` is not final, but var
count += 1;

// You can also compare against values:
count > 2;

/// booleans:

final flag = false.obs;

// switches the value between true/false
flag.toggle();


/// all types:

// Sets the `value` to null.
flag.nil();

// All toString(), toJson() operations are passed down to the `value`
print( count ); // calls `toString()` inside  for RxInt

final abc = [0,1,2].obs;
// Converts the value to a json Array, prints RxList
// Json is supported by all Rx types!
print('json: ${jsonEncode(abc)}, type: ${abc.runtimeType}');

// RxMap, RxList and RxSet are special Rx types, that extends their native types.
// but you can work with a List as a regular list, although is reactive!
abc.add(12); // pushes 12 to the list, and UPDATES the stream.
abc[3]; // like Lists, reads the index 3.


// equality works with the Rx and the value, but hashCode is always taken from the value
final number = 12.obs;
print( number == 12 ); // prints > true

/// Custom Rx Models:

// toJson(), toString() are deferred to the child, so you can implement override on them, and print() the observable directly.

class User {
    String name, last;
    int age;
    User({this.name, this.last, this.age});

    @override
    String toString() => '$name $last, $age years old';
}

final user = User(name: 'John', last: 'Doe', age: 33).obs;

// `user` is "reactive", but the properties inside ARE NOT!
// So, if we change some variable inside of it...
user.value.name = 'Roi';
// The widget will not rebuild!,
// `Rx` don't have any clue when you change something inside user.
// So, for custom classes, we need to manually "notify" the change.
user.refresh();

// or we can use the `update()` method!
user.update((value){
  value.name='Roi';
});

print( user );

StateMixin

Another way to handle your UI state is use the StateMixin<T> . To implement it, use the with to add the StateMixin<T> to your controller which allows a T model.

class Controller extends GetController with StateMixin<User>{}

The change() method change the State whenever we want. Just pass the data and the status in this way:

change(data, status: RxStatus.success());

RxStatus allow these status:

RxStatus.loading();
RxStatus.success();
RxStatus.empty();
RxStatus.error('message');

To represent it in the UI, use:

class OtherClass extends GetView<Controller> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(

      body: controller.obx(
        (state)=>Text(state.name),

        // here you can put your custom loading indicator, but
        // by default would be Center(child:CircularProgressIndicator())
        onLoading: CustomLoadingIndicator(),
        onEmpty: Text('No data found'),

        // here also you can set your own error widget, but by
        // default will be an Center(child:Text(error))
        onError: (error)=>Text(error),
      ),
    );
}

গেট ভিউ (GetView)

I love this Widget, is so simple, yet, so useful!

Is a const Stateless Widget that has a getter controller for a registered Controller, that's all.

 class AwesomeController extends GetController {
   final String title = 'My Awesome View';
 }

  // ALWAYS remember to pass the `Type` you used to register your controller!
 class AwesomeView extends GetView<AwesomeController> {
   @override
   Widget build(BuildContext context) {
     return Container(
       padding: EdgeInsets.all(20),
       child: Text(controller.title), // just call `controller.something`
     );
   }
 }

গেট রেস্পন্সিভ ভিউ (GetResponsiveView)

Extend this widget to build responsive view. this widget contains the screen property that have all information about the screen size and type.

কিভাবে এটি ব্যবহার করতে হয়

You have two options to build it.

  • with builder method you return the widget to build.
  • with methods desktop, tablet,phone, watch. the specific method will be built when the screen type matches the method when the screen is [ScreenType.Tablet] the tablet method will be exuded and so on. Note: If you use this method please set the property alwaysUseBuilder to false

With settings property you can set the width limit for the screen types.

example Code to this screen code

গেট উইজেট (GetWidget)

Most people have no idea about this Widget, or totally confuse the usage of it. The use case is very rare, but very specific: It caches a Controller. Because of the cache, can't be a const Stateless.

So, when do you need to "cache" a Controller?

If you use, another "not so common" feature of GetX: Get.create().

Get.create(()=>Controller()) will generate a new Controller each time you call Get.find<Controller>(),

That's where GetWidget shines... as you can use it, for example, to keep a list of Todo items. So, if the widget gets "rebuilt", it will keep the same controller instance.

গেট এক্স সার্ভিস (GetxService)

This class is like a GetxController, it shares the same lifecycle ( onInit(), onReady(), onClose()). But has no "logic" inside of it. It just notifies GetX Dependency Injection system, that this subclass can not be removed from memory.

So is super useful to keep your "Services" always reachable and active with Get.find(). Like: ApiService, StorageService, CacheService.

Future<void> main() async {
  await initServices(); /// AWAIT SERVICES INITIALIZATION.
  runApp(SomeApp());
}

/// Is a smart move to make your Services intiialize before you run the Flutter app.
/// as you can control the execution flow (maybe you need to load some Theme configuration,
/// apiKey, language defined by the User... so load SettingService before running ApiService.
/// so GetMaterialApp() doesnt have to rebuild, and takes the values directly.
void initServices() async {
  print('starting services ...');
  /// Here is where you put get_storage, hive, shared_pref initialization.
  /// or moor connection, or whatever that's async.
  await Get.putAsync(() => DbService().init());
  await Get.putAsync(SettingsService()).init();
  print('All services started...');
}

class DbService extends GetxService {
  Future<DbService> init() async {
    print('$runtimeType delays 2 sec');
    await 2.delay();
    print('$runtimeType ready!');
    return this;
  }
}

class SettingsService extends GetxService {
  void init() async {
    print('$runtimeType delays 1 sec');
    await 1.delay();
    print('$runtimeType ready!');
  }
}

The only way to actually delete a GetxService, is with Get.reset() which is like a "Hot Reboot" of your app. So remember, if you need absolute persistence of a class instance during the lifetime of your app, use GetxService.

পরীক্ষা (Tests)

You can test your controllers like any other class, including their lifecycles:

class Controller extends GetxController {
  @override
  void onInit() {
    super.onInit();
    //Change value to name2
    name.value = 'name2';
  }

  @override
  void onClose() {
    name.value = '';
    super.onClose();
  }

  final name = 'name1'.obs;

  void changeName() => name.value = 'name3';
}

void main() {
  test('''
Test the state of the reactive variable "name" across all of its lifecycles''',
      () {
    /// You can test the controller without the lifecycle,
    /// but it's not recommended unless you're not using
    ///  GetX dependency injection
    final controller = Controller();
    expect(controller.name.value, 'name1');

    /// If you are using it, you can test everything,
    /// including the state of the application after each lifecycle.
    Get.put(controller); // onInit was called
    expect(controller.name.value, 'name2');

    /// Test your functions
    controller.changeName();
    expect(controller.name.value, 'name3');

    /// onClose was called
    Get.delete<Controller>();

    expect(controller.name.value, '');
  });
}

পরামর্শ

Mockito or mocktail

If you need to mock your GetxController/GetxService, you should extend GetxController, and mixin it with Mock, that way

class NotificationServiceMock extends GetxService with Mock implements NotificationService {}
Using Get.reset()

If you are testing widgets, or test groups, use Get.reset at the end of your test or in tearDown to reset all settings from your previous test.

Get.testMode

if you are using your navigation in your controllers, use Get.testMode = true at the beginning of your main.

2.0 থেকে পরিবর্তন

1- Rx এর প্রকারভেদ :

পূর্বে এখন
StringX RxString
IntX RxInt
MapX RxMap
ListX RxList
NumX RxNum
DoubleX RxDouble

RxController এবং GetBuilder এখন একত্রিত, আপনি কোন নিয়ামক ব্যবহার করতে চান তা আর মুখস্ত করার দরকার নেই, শুধু GetxController ব্যবহার করুন, এটি সাধারণ স্টেট ব্যবস্থাপনা এবং প্রতিক্রিয়াশীল স্টেট ব্যবস্থাপনা এর জন্যও কাজ করবে।

2- নেমড রুটস (NamedRoutes)

আগে:

GetMaterialApp(
  namedRoutes: {
    '/': GetRoute(page: Home()),
  }
)

এখন:

GetMaterialApp(
  getPages: [
    GetPage(name: '/', page: () => Home()),
  ]
)

কেন এই পরিবর্তন? প্রায়শই, কোন পৃষ্ঠাটি প্যারামিটার বা লগইন টোকেন থেকে প্রদর্শিত হবে তা নির্ধারণ করার প্রয়োজন হতে পারে, পূর্ববর্তী পদ্ধতিটি অনমনীয় ছিল, কারণ এটি সেই অনুমতি দিতো না। এটি ফাংশনে পৃষ্ঠাটি ইনসার্ট করার জন্য উল্লেখযোগ্যভাবে RAM খরচ হ্রাস করেছে, যেহেতু অ্যাপটি শুরু হওয়ার পর থেকে রুটগুলি মেমরিতে বরাদ্দ করা হবে না, এটি এই ধরণের পদ্ধতিরও অনুমতি দেয়:


GetStorage box = GetStorage();

GetMaterialApp(
  getPages: [
    GetPage(name: '/', page:(){
      return box.hasData('token') ? Home() : Login();
    })
  ]
)