states_rebuilder #

• Code Clean

  • Zero Boilerplate
  • No annotation & code-generation
  • Separation of UI & business logic
  • Achieve business logic in pure Dart.

• User Friendly

  • Built-in dependency injection system
  • SetState in StatelessWidget.
  • Hot-pluggable Stream / Futures
  • Easily Undo / Redo
  • Elegant error handling and refreshing
  • Navigate, show dialogs without BuildContext
  • Named route with dynamic segmenet
  • Nested routes mapping
  • Easily persist the state and retrieve it back
  • Override the state for a particular widget tree branch (widget-wise state)

• development-time-saving

  • Easily CREATE, READ, UPDATE, and DELETE (CRUD) from rest-API or database.
  • Easy user authentication and authorization.
  • Easily app themes management.
  • Simple internalization and localization.
  • Work with TextFields and Form validation, both in client and server side.
  • Implicit animation with the power of explicit animation.
  • Easy and user friendly interface for ScrollControllers

• Maintainable

  • Easy to test, mock the dependencies
  • state tracker middleware
  • Built-in debugging print function
  • Capable for complex apps

Table of Contents #

• Getting Started with States_rebuilder
• Breaking Changes
• A Quick Tour of states_rebuilder API
  • Business logic and state injection
  • State change and notification
  • State subscription and widget rebuild
  • State persistence
  • Undo and redo immutable state
  • Route management
  • Create, Read, Update and Delete items from backend service
  • Authentication and authorization
  • Dynamic theme switching
  • App internationalization
  • Implicit and explicit animation
  • Working with TextFields and Form validation
  • Working with scrollable view
  • Working with page and tab views
  • Test and injected state mocking
• Examples:

Getting Started with States_rebuilder #

1. Add the latest version to your package's pubspec.yaml file.

2. Import it in any Dart code:

import 'package:states_rebuilder/states_rebuilder.dart';

3. Basic use case:

// 🗄️Plain Data Class
class Model {
  int counter;

  Model(this.counter);
}  

// 🤔Business Logic - Service Layer
extension ModelX on Model {
  increment() => this.counter++;  
}

// 🚀Global Functional Injection 
// This state will be auto-disposed when no longer used, and also testable and mockable.
final model = RM.inject<Model>(
  () => Model(0), 
  undoStackLength: 8,
  //Called after new state calculation and just before state mutation
  middleSnapState: (MiddleSnapState middleSnap){
    //Log all state transition.
    print(middleSnap.currentSnap);
    print(middleSnap.nextSnap);

    middleSnap.print()//Build-in logger

    //Can return another state
  }
);

// 👀UI  
class CounterApp extends StatelessWidget {
  const CounterApp();
  
  @override
  Widget build(BuildContext context) {
    return Column (
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: [
            ElevatedButton(
                child: const Text('🏎️ Counter ++'),
                onPressed: () => model.setState(
                    (s) => s.increment(),
                ),
            ),
            RaisedButton(
                child: const Text('⏱️ Undo'),
                onPressed: () => model.undoState(),
            ),
            OnReactive(
              () => Text('🏁Result: ${model.state.counter}'),
            ),
        ],
    );
  }  
}

Breaking Changes #

Since 4.0:   Here #

Since 3.0:   Here #

Since 2.0:   Here #

A Quick Tour of states_rebuilder API #

Business logic and state injection #

The business logic classes are independent from any external library. They are independent even from states_rebuilder itself.

The specificity of states_rebuilder is that it has practically no boilerplate. It has no boilerplate to the point that you do not have to monitor the asynchronous state yourself. You do not need to add fields to hold for example onLoading, onLoaded, onError states. states_rebuilder automatically manages these asynchronous statuses and exposes the isIdle, isWaiting, hasError and hasData getters and onIdle, onWaiting, onError and onData hooks for use in the user interface logic.

With states_rebuilder, you write business logic without bearing in mind how the user interface would interact with it.

This is a typical simple business logic class:

class Foo { //don't extend any other library specific class
  int mutableState = 0; // the state can be mutable
  //Or
  final int immutableState; // Or it can be immutable (no difference)
  Foo(this.immutableState);

  Future<int> fetchSomeThing async(){
    //No need for any kind of async state tracking variables
    return repository.fetchSomeThing();
    //No need for any kind of notification
  }

  Stream<int> streamSomeThing async*(){
    //Methods can return stream, future, or simple sync objects,
    //states_rebuilder treats them equally
  }
}

To make the Foo object reactive, we simply inject it using global functional injection:

final Injected<Foo> foo = RM.inject<Foo>(
  ()=> Foo(),
  onInitialized : (Foo state) => print('Initialized'),
  // Default callbacks for side effects.
  onSetState: On.all(
    onIdle: () => print('Is idle'),
    onWaiting: () => print('Is waiting'),
    onError: (error) => print('Has error'),
    onData: (Foo data) => print('Has data'),
  ),
  // It is disposed when no longer needed
  onDisposed: (Foo state) => print('Disposed'),
  // To persist the state
  persist:() => PersistState(
      key: '__FooKey__',
      toJson: (Foo s) => s.toJson(),
      fromJson: (String json) => Foo.fromJson(json),
      // Optionally, throttle the state persistance
      throttleDelay: 1000,
  ),
  // middleSnapState as a middleWare place
  // Used to track and log state lifecycle and transitions.
  // It can also be used to return another state created from 
  // the current state and the next state.
  middleSnapState: (middleSnap) {
     middleSnap.print(); //Build-in logger
    
    // Example of simple email validation
    if (middleSnap.nextSnap.hasData) {
      if (!middleSnap.nextSnap.data.contains('@')) {
        return middleSnap.nextSnap.copyToHasError(
          Exception('Enter a valid Email'),
        );
      }
    }
  },
);
//For simple injection you can use `inj()` extension:
final foo = Foo().inj<Foo>();
final isBool = false.inj();
final string = 'str'.inj();
final count = 0.inj();

Injected interface is a wrapper class that encloses the state we want to inject. The state can be mutable or immutable.

Injected state can be instantiated globally or as a member of classes. They can be instantiated inside the build method without losing the state after rebuilds.

To inject a state, you use RM.inject, RM.injectFuture, RM.injectStream or RM.injectFlavor.

The injected state even if it is injected globally it has a lifecycle. It is created when first used and destroyed when no longer used. Between the creation and the destruction of the state, it can be listened to and mutated to notify its registered listeners.

When the state is disposed of, its list of listeners is cleared, and if the state is waiting for a Future or subscribed to a Stream, it will cancel them to free resources.

Injected state can depend on other Injected states and recalculate its state and notify its listeners whenever any of its of the Inject model that it depends on emits a notification.

🗎 See more detailed information about the RM.injected API.

State change and notification #

To mutate the state and notify listener:

//Inside any callback: 
foo.state= newFoo;
//Or for more options

foo.setState(
  (s) => s.fetchSomeThing(),
  onSetState: On.waiting(()=> showSnackBar() ),
  debounceDelay : 400,
)

//if state is bool
foo.toggle();

The state when mutated emits a notification to its registered listeners. The emitted notification has a boolean flag to describe is status :

• isIdle : the state is first created and no notification is emitted yet.
• isWaiting: the state is waiting for an async task to end.
• hasError: the state mutation has ended with an error.
• hasData: the state mutation has ended with valid data.
• isActive: the state had data at least one time.

🗎 See more detailed information about setState API.

You can notify listeners without changing the state using :

foo.notify();

You can also refresh the state to its initial state and reinvoke the creation function then notify listeners using:

foo.refresh();

refresh is useful to re-execute async data fetching to get the updated data from a server. Typical use is the refresh a ListView display.

If the state is persisted, calling refresh will delete the persisted state and replace it with the newly created one.

Calling refresh will cancel any pending async task from the state before refreshing.

🗎 See more detailed information about the refresh API.

State subscription and widget rebuild #

To listen to an injected state and rebuild a part of the widget tree, just wrap that part of the widget tree inside OnReactive widget:

final counter1 = RM.inject(()=> 0) // Or just use extension: 0.inj()
final counter2 = 0.inj();
int get sum => counter1.state + counter2.state;

//In the widget tree:
Column(
    children: [
        OnReactive( // Will listen to counter1
            ()=> Text('${counter1.state}');
        ),
        OnReactive( // Will listen to counter2
            ()=> Text('${counter2.state}');
        ),
        OnReactive(// Will listen to both counter1 and counter2
            ()=> Text('$sum');
        )
    ]
)

Inside OnReactive you can call any of the available state status flags (isWaiting, hasError, hasData, ...) or just use onAll and onOrElse methods:

OnReactive(
    ()=> {
        if(myModel.isWaiting){
            return WaitingWidget();
        }
        if(myModel.hasError){
            return ErrorWidget();
        }
        return DataWidget();
    }
)
//Or use onAll method:
OnReactive(
    ()=> myModel.onAll(
            onWaiting: ()=> WaitingWidget(),
            onError: (err, refreshErr)=> ErrorWidget(),
            onDate: (data)=> DataWidget(),
        );
)

//Or use onOr method:
OnReactive(
    ()=> myModel.onOrElse(
            onWaiting: ()=> WaitingWidget(),
            orElse: (data)=> DataWidget(),
        );
)

Similar to OnReactive widget there is the abstract widget ReactiveStatelessWidget. When the ReactiveStatelessWidget is used instead of StatelessWidget, the widget becomes reactive and implicitly tracks its listeners no matter how deep in the widget tree they are provided that the widget is not loaded lazily such as inside the builder method of the ListView.builder widget:

class MyWidget extends ReactiveStatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
          Text('${counter1.state}'),
          Text('${counter2.state}'),
          Text('$sum'),
      ]
    );
  }
}

• 🗎 See more detailed information about OnReactive API.

• Here is an example demonstrating the basic ideas.

In most cases OnReactive do the job. Nevertheless, if you want to explicitly specify the listeners you want to listen to, use OnBuilder widget.

OnBuilder(
    listenTo: myState,
    //called whenever myState emits a notification
    builder: () => Text('${counter.state}'),
    sideEffect: SideEffect(
        initState: () => print('initState'),
        onSetState: On(() => print('onSetState')),
        onAfterBuild: On(() => print('onAfterBuild')),
        dispose: () => print('dispose'),
    ),
    shouldRebuild: (oldSnap, newSnap) {
      return true;
    },
    debugPrintWhenRebuild: 'myState',
),

If you want to listen to many injected states use listenToMany parameter.

In this case onBuilder will react to a combined state of all injected states.

OnBuilder.all(
    listenToMany: [myState1, myState2],
    onWaiting: () => Text('onWaiting'), // Will be invoked if at least one state iwaiting
    onError: (err, refreshError) => Text('onError'), // Will be invoked if at least onstate has error
    onData: (data) => Text(myState.state.toString()), // Will be invoked if all states have data.
),

• 🗎 See more detailed information about OnReactive API.

states_rebuilder offers callbacks to handle the state status change. The state status callbacks are conveniently defined using the On class with its named constructor alternatives:

// Called when notified regardless of state status of the notification
On(()=> print('on'));
// Called when notified with data status
On.data(()=> print('data'));
// Called when notified with waiting status
On.waiting(()=> print('waiting'));
// Called when notified with error status
On.error((err, refresh)=> print('error'));
// Exhaustively handle all four status
On.all(
  onIdle: ()=> print('Idle'), // If is Idle
  onWaiting: ()=> print('Waiting'), // If is waiting
  onError: (err, refresh)=> print('Error'), // If has error 
  onData:  ()=> print('Data'), // If has Data
)
// Optionally handle the four status
On.or(
  onWaiting: ()=> print('Waiting'),
  onError: (err, refresh)=> print('Error'),
  onData:  ()=> print('Data'),
  or: () =>  print('or')
)

All onError callbacks expose a refresher. It can be use to refresh the error; that is recalling the last function that caused the error.

If you want to optimize widget rebuild and prevent some part of the child widget tree from unnecessary rebuilding, use Child, Child2, Child3 widget.

Child(
  (child) => OnReactive(
      () => Colum(
          children: [
              Text('model.state'), // This part will rebuild
              child, //This part will not rebuild
          ],
      ),
  ),
  child: WidgetNotToRebuild(),
);

You can make your state widget-wise and override it to present different branches of the widget tree.

final items = [1,2,3];

final item = RM.inject(()=>null);

class App extends StatelessWidget{
  build (context){
    return ListView.builder(
      itemCount: items.length,
      itemBuilder: (BuildContext context, int index) {
        return item.inherited( //inherited uses the InheritedWidget concept
          stateOverride: () => items[index],
          builder: () {

            return const ItemWidget();
            //Inside ItemWidget you can use the buildContext to get 
            //the right state for each widget branch using:
            item.of(context); //the Element owner of context is registered to item model.
            //or
            item(context) //the Element owner of context is not registered to item model.
          }
        );
      },
    );
  }
}

• 🗎 See more detailed information about the topic of state widget-wise and InheritedWidget

State persistence #

To Persist the state and retrieve it when the app restarts,

final model = RM.inject<MyModel>(
    ()=>MyModel(),
  persist:() => PersistState(
    key: 'modelKey',
    toJson: (MyModel s) => s.toJson(),
    fromJson: (String json) => MyModel.fromJson(json),
    //Optionally, throttle the state persistance
    throttleDelay: 1000,
  ),
);

You can manually persist or delete the state

model.persistState();
model.deletePersistState();

• 🗎 See more detailed information about state persistance.

• Here is an example of state persistence.

Undo and redo immutable state #

To undo and redo immutable state:

model.undoState();
model.redoState();

🗎 See more detailed information about undo redo state.

• Here is an example on how to undo and redo the state.

Route management #

To navigate, show dialogs and snackBars without BuildContext:

RM.navigate.to(HomePage());

RM.navigate.to('/namePage');

RM.navigate.toDialog(AlertDialog( ... ));

RM.scaffoldShow.snackbar(SnackBar( ... ));

You can easily change page transition animation, using one of the predefined TransitionBuilder or just define yours.

You can use dynamic segments with named routing

  return MaterialApp(
      navigatorKey: RM.navigate.navigatorKey,
      onGenerateRoute: RM.navigate.onGenerateRoute({
        '/': (_) => LoginPage(),
        '/posts': (_) => RouteWidget(
              routes: {
                '/:author': (RouteData data) {
                    final queryParams = data.queryParams;
                    final pathParams = data.pathParams;
                    final arguments = data.arguments;

                    //OR
                    //Inside a child widget of AuthorWidget :
                    //
                    //context.routeQueryParams;
                    //context.routePathParams;
                    //context.routeArguments;
                    return  AuthorWidget();

                },
                '/postDetails': (_) => PostDetailsWidget(),
              },
            ),
        '/settings': (_) => SettingsPage(),
      }),
    );

In the UI:

  RM.navigate.to('/'); // => renders LoginPage()
  RM.navigate.to('/posts'); // => 404 error
  RM.navigate.to('/posts/foo'); // =>  renders AuthorWidget(), with pathParams = {'author' : 'foo' }
  RM.navigate.to('/posts/postDetails'); // =>  renders PostDetailsWidget(),
  //If you are in AuthorWidget you can use relative path (name without the back slash at the beginning)
  RM.navigate.to('postDetails'); // =>  renders PostDetailsWidget(),
  RM.navigate.to('postDetails', queryParams : {'postId': '1'}); // =>  renders PostDetailsWidget(),

• 🗎 See more detailed information about router.

Create, Read, Update and Delete items from backend service #

• To Create, Read, Update and Delete (CRUD) from backend or DataBase,

  final products = RM.injectCRUD<Product, Param>(
      ()=> MyProductRepository(),//Implements ICRUD<Product, Param>
      readOnInitialization: true,// Optional (Default is false)
  );
  

  //READ
  products.crud.read(param: (param)=> NewParam());
  //CREATE
  products.crud.create(NewProduct());
  //UPDATE
  products.crud.update(
    where: (product) => product.id == 1,
    set: (product)=> product.copyWith(...),
  );
  //DELETE
  products.crud.delete(
    where: (product) => product.id == 1,
    isOptimistic: false, // Optional (Default is true)
  );
  

  • 🗎 See more detailed information about InjectCRUD.

  • Here is a working example of a CRUD app.

Authentication and authorization #

To authenticate and authorize users,

final user = RM.injectAuth<User, Param>(
    ()=> MyAuthRepository(),//Implements IAuth<User, Param>
    unSignedUser: UnsignedUser(),
    onSigned: (user)=> //Navigate to home page,
    onUnsigned: ()=> //navigate to Auth Page,
    autoSignOut: (user)=> Duration(seconds: user.tokenExpiryDate)
);

//Sign up
user.auth.signUp((param)=> Param());
//Sign in
user.auth.signIn((param)=> Param());
//Sign out
user.auth.signOut();

• 🗎 See more detailed information about InjectAuth.

• Here is a typical auth app.

Dynamic theme switching #

To dynamically switch themes,

final theme = RM.injectTheme<String>(
    lightThemes : {
      'simple': ThemeData.light( ... ),
      'solarized': ThemeData.light( ...),
    },
    darkThemes: {
      'simple': ThemeData.dark( ... ),
      'solarized': ThemeData.dark( ...),
    };
    themeMode: ThemeMode.system;
    persistKey: '__theme__',
);

//choose the theme
theme.state = 'solarized'
//toggle between dark and light mode of the chosen them
theme.toggle();

• 🗎 See more detailed information about InjectedTheme.

• Here is an example on dynamic theming.

App internationalization #

To internationalize and localize your app:

//US english
class EnUS {
  final helloWorld = 'Hello world';
}
//Spanish
class EsEs implements EnUs{
  final helloWorld = 'Hola Mondo';
}

final i18n = RM.injectI18N<EnUS>(
    {
      Local('en', 'US'): ()=> EnUS();//can be async
      Local('es', 'ES'): ()=> EsES();
    };
    persistKey: '__lang__', //local persistance of language 
);

In the UI:

Text(i18n.of(context).helloWorld);

//choose the language
i18n.locale = Local('es', 'Es');
//Or choose the system language
i18n.locale = SystemLocale();

• 🗎 See more detailed information about InjectedI18N.

• Here is an example on app internationalization.

To set an animation:

Implicit and explicit animation #

final animation = RM.injectAnimation(
  duration: const Duration(seconds: 1),
  curve: Curves.linear,
);

In the UI: For Implicit animation

Center(
  child: OnAnimationBuilder(
      listenTo: animation,
      builder: (animate) => Container(
          // Animate is a callable class
          width: animate.call(selected ? 200.0 : 100.0),
          height: animate(selected ? 100.0 : 200.0, 'height'),
          color: animate(selected ? Colors.red : Colors.blue),
          alignment: animate(selected ? Alignment.center : AlignmentDirectional.topCenter),
          child: const FlutterLogo(size: 75),
      ),
  ),
),

For explicit animation

OnAnimationBuilder(
  listenTo: animation,
  builder: (animate) => Transform.rotate(
  angle: animate.formTween(
      (currentValue) => Tween(begin: 0, end: 2 * 3.14),
  )!,
  child: const FlutterLogo(size: 75),
  ),
),

• 🗎 See more detailed information about InjectedAnimation.

• Here are many show cases of implicit and explicit animation.

Working with TextFields and Form validation #

To deal with TextFields and Form validation

final email =  RM.injectTextEditing():

final password = RM.injectTextEditing(
  validator: (String? value) {
    if (value!.length < 6) {
      return "Password must have at least 6 characters";
    }
    return null;
  },
);

final form = RM.injectForm(
  autovalidateMode: AutovalidateMode.disable,
  autoFocusOnFirstError: true,
  submit: () async {
    //This is the default submission logic,
    //It may be override when calling form.submit( () async { });
    //It may contains server validation.
    await serverError =  authRepository.signInWithEmailAndPassword(
        email: email.text,
        password: password.text,
      );
      //after server validation
      if(serverError == 'Invalid-Email'){
        email.error = 'Invalid email';
      }
      if(serverError == 'Weak-Password'){
        email.error = 'Password must have more the 6 characters';
      }
  },
  onSubmitting: () {
    // called while waiting for form submission,
  },
  onSubmitted: () {
    // called after form is successfully submitted
    // For example navigation to user page
  }
);

In the UI:

  OnFormBuilder(
    listenTo: form,
    builder: () => Column(
      children: <Widget>[
          TextField(
              focusNode: email.focusNode,
              controller: email.controller,
              decoration: InputDecoration(
                errorText: email.error,
              ),
              onSubmitted: (_) {
                //request the password node
                password.focusNode.requestFocus();
              },
          ),
          TextField(
              focusNode: password.focusNode,
              controller: password.controller,
              decoration: new InputDecoration(
                errorText: password.error,
              ),
              onSubmitted: (_) {
                //request the submit button node
                form.submitFocusNode.requestFocus();
              },
          ),
          OnFormSubmissionBuilder(
            listenTo: form,
            onSubmitting: () => CircularProgressIndicator(),
            child : ElevatedButton(
              focusNode: form.submitFocusNode,
              onPressed: (){
                  form.submit();
              },
              child: Text('Submit'),
            ),
          ),     
      ],
    ),
),

• 🗎 See more detailed information about InjectedTextEditing and InjectedForm.

Working with scrollable view #

• To work with scrolling list:

final scroll = RM.injectScrolling(
  initialScrollOffset: 0.0,
  keepScrollOffset: true,
  endScrollDelay: 300,
  onScrolling: (scroll){
    if (scroll.hasReachedMinExtent) {
    print('Scrolling vertical list is in its top position');
    }
    if (scroll.hasReachedMaxExtent) {
      print('Scrolling vertical list is in its bottom position');
    }

    if (scroll.hasStartedScrolling) {
      //Called only one time.
      print('User has just start scrolling');
    }
  }
);

In the UI:

ListView(
    controller: scroll.controller,
    children: <Widget>[],
)

• 🗎 See more detailed information about InjectedScrolling.

Working with page and tab views #

Test and injected state mocking #

All Injected state can be mocked for test. To mock it in test:

  model.injectMock(()=> MyMockModel());
  model.injectFutureMock(()=> MyMockModel());
  products.injectCRUDMock(()=> MockRepository())
  user.injectAuthMock(()=> MockAuthRepository())

And many more features.

Examples: #

Basics: #

Since you are new to states_rebuilder, this is the right place for you to explore. The order below is tailor-made for you 😃:

• Hello world app: Hello world app. It gives you the most important feature simply by say hello world. You will understand the concept of global function injection and how to make a pure dart class reactive. You will see how an injected state can depends on other injected state to be refreshed when the other injected state emits notification.

• The simplest counter app: Default flutter counter app refactored using states_rebuilder.

• Login form validation: Simple form login validation. The basic Injected concepts are put into practice to make form validation one of the easiest tasks in the world. The concept of exposed model is explained here.

• CountDown timer. This is a timer that ticks from 60 and down to 0. It can be paused, resumed or restarted.

• Theming and internationalization. This is a demonstration how to handle theme switching and app internationalization using RM.injectedTheme and RM.injectedI18N.

• CRUD query. This is an example of a backend service fetching data app. The app performs CRUD operation using RM.injectCRUD.

• Infinite scroll listView. This is another example of CRUD operation using RM.injectCRUD. More items will be fetched when the list reaches its bottom.

Advanced: #

Here, you will take your programming skills up a notch, deep dive in Architecture 🧐:

• User posts and comments: The app communicates with the JSONPlaceholder API, gets a User profile from the login using the ID entered. Fetches and shows the Posts on the home view and shows post details with an additional fetch to show the comments.

Firebase Series: #

• Firebase login The app uses firebase for sign in. The user can sign in anonymously, with google account, with apple account or with email and password.

Firestore Series in Todo App: #

TODOS MVC app The same examples as above adding the possibility for a user to sin up and log in. A user will only see their own todos. The log in will be made with a token which, once expired, the user will be automatically disconnected.