Widgets that make it easy to integrate blocs and cubits into Flutter. Built to work with package:bloc.
BLOCS 2.0.1 May 12, 2016 Fixed. Fixed issue that caused site options to crash with 1.6 projects. Fixed issue that caused app to crash when deleting a global swatch. Fixed issue that caused form php files to not be generated on export.
BLOC 3 PRISES AVEC INTERRUPTEUR PROTECTION ENFANTS HO5VVF 3G1.0 ELE100 Page catalogue: 2449 Suremballage: 40 En stock -+ Vendu par. Bloc has 115 repositories available. Follow their code on GitHub. Skip to content. JavaScript Apache-2.0 40 11 1 0 Updated Jul 28, 2017. Messenger This is a small app to message using the Bloc Api JavaScript 3 7 18 (6 issues need help) 0 Updated Jul 17, 2017. EBay Bloc LocHalf Square Triangle Ruler Set #1-1.5',2.5',3.5',4.5',5.5', 6.5', Acrylic Ruler PRODUCT DESCRIPTION Bloc Loc's half square triangle rulers make the tough job of squaring up easy and fast. The groove slides along the seam to trim smaller units and allows quilters to. Blocs for Mac is a fast, easy-to-use, powerful visual web-design tool that lets you create beautiful, modern websites without the need to write code. Cleverly designed to accommodate complete beginners or those familiar with web design.
Learn more at bloclibrary.dev!
*Note: All widgets exported by the flutter_bloc package integrate with both Cubit and Bloc instances.
Sponsors #
Our top sponsors are shown below! [Become a Sponsor]
Try the Flutter Chat Tutorial 💬 |
Usage #
Lets take a look at how to use BlocBuilder to hook up a CounterPage widget to a CounterCubit.
counter_cubit.dart #
counter_page.dart #
At this point we have successfully separated our presentational layer from our business logic layer. Notice that the CounterPage widget knows nothing about what happens when a user taps the buttons. The widget simply tells the CounterCubit that the user has pressed either the increment or decrement button.
Bloc Widgets #
BlocBuilder #
BlocBuilder is a Flutter widget which requires a cubit and a builder function. BlocBuilder handles building the widget in response to new states. BlocBuilder is very similar to StreamBuilder but has a more simple API to reduce the amount of boilerplate code needed. The builder function will potentially be called many times and should be a pure function that returns a widget in response to the state.
See BlocListener if you want to 'do' anything in response to state changes such as navigation, showing a dialog, etc..
If the cubit parameter is omitted, BlocBuilder will automatically perform a lookup using BlocProvider and the current BuildContext.
Only specify the cubit if you wish to provide a cubit that will be scoped to a single widget and isn't accessible via a parent BlocProvider and the current BuildContext.
For fine-grained control over when the builder function is called an optional buildWhen can be provided. buildWhen takes the previous cubit state and current cubit state and returns a boolean. If buildWhen returns true, builder will be called with state and the widget will rebuild. If buildWhen returns false, builder will not be called with state and no rebuild will occur.
BlocProvider #
BlocProvider is a Flutter widget which provides a cubit to its children via BlocProvider.of(context). It is used as a dependency injection (DI) widget so that a single instance of a cubit can be provided to multiple widgets within a subtree.
In most cases, BlocProvider should be used to create new cubits which will be made available to the rest of the subtree. In this case, since BlocProvider is responsible for creating the cubit, it will automatically handle closing it.
By default, BlocProvider will create the cubit lazily, meaning create will get executed when the cubit is looked up via BlocProvider.of(context).
To override this behavior and force create to be run immediately, lazy can be set to false.
In some cases, BlocProvider can be used to provide an existing cubit to a new portion of the widget tree. This will be most commonly used when an existing cubit needs to be made available to a new route. In this case, BlocProvider will not automatically close the cubit since it did not create it.
then from either ChildA, or ScreenA we can retrieve BlocA with:
The above snippets result in a one time lookup and the widget will not be notified of changes. To retrieve the instance and subscribe to subsequent state changes use:
In addition, context.select can be used to retrieve part of a state and react to changes only when the selected part changes.
The snippet above will only rebuild if the state of the CounterBloc changes from positive to negative or vice versa.
*Note: All widgets exported by the flutter_bloc package integrate with both Cubit and Bloc instances.
Sponsors #
Our top sponsors are shown below! [Become a Sponsor]
Try the Flutter Chat Tutorial 💬 |
Usage #
Lets take a look at how to use BlocBuilder to hook up a CounterPage widget to a CounterCubit.
counter_cubit.dart #
counter_page.dart #
At this point we have successfully separated our presentational layer from our business logic layer. Notice that the CounterPage widget knows nothing about what happens when a user taps the buttons. The widget simply tells the CounterCubit that the user has pressed either the increment or decrement button.
Bloc Widgets #
BlocBuilder #
BlocBuilder is a Flutter widget which requires a cubit and a builder function. BlocBuilder handles building the widget in response to new states. BlocBuilder is very similar to StreamBuilder but has a more simple API to reduce the amount of boilerplate code needed. The builder function will potentially be called many times and should be a pure function that returns a widget in response to the state.
See BlocListener if you want to 'do' anything in response to state changes such as navigation, showing a dialog, etc..
If the cubit parameter is omitted, BlocBuilder will automatically perform a lookup using BlocProvider and the current BuildContext.
Only specify the cubit if you wish to provide a cubit that will be scoped to a single widget and isn't accessible via a parent BlocProvider and the current BuildContext.
For fine-grained control over when the builder function is called an optional buildWhen can be provided. buildWhen takes the previous cubit state and current cubit state and returns a boolean. If buildWhen returns true, builder will be called with state and the widget will rebuild. If buildWhen returns false, builder will not be called with state and no rebuild will occur.
BlocProvider #
BlocProvider is a Flutter widget which provides a cubit to its children via BlocProvider.of(context). It is used as a dependency injection (DI) widget so that a single instance of a cubit can be provided to multiple widgets within a subtree.
In most cases, BlocProvider should be used to create new cubits which will be made available to the rest of the subtree. In this case, since BlocProvider is responsible for creating the cubit, it will automatically handle closing it.
By default, BlocProvider will create the cubit lazily, meaning create will get executed when the cubit is looked up via BlocProvider.of(context).
To override this behavior and force create to be run immediately, lazy can be set to false.
In some cases, BlocProvider can be used to provide an existing cubit to a new portion of the widget tree. This will be most commonly used when an existing cubit needs to be made available to a new route. In this case, BlocProvider will not automatically close the cubit since it did not create it.
then from either ChildA, or ScreenA we can retrieve BlocA with:
The above snippets result in a one time lookup and the widget will not be notified of changes. To retrieve the instance and subscribe to subsequent state changes use:
In addition, context.select can be used to retrieve part of a state and react to changes only when the selected part changes.
The snippet above will only rebuild if the state of the CounterBloc changes from positive to negative or vice versa.
MultiBlocProvider #
MultiBlocProvider is a Flutter widget that merges multiple BlocProvider widgets into one.MultiBlocProvider improves the readability and eliminates the need to nest multiple BlocProviders.By using MultiBlocProvider we can go from:
to:
BlocListener #
BlocListener is a Flutter widget which takes a BlocWidgetListener and an optional cubit and invokes the listener in response to state changes in the cubit. It should be used for functionality that needs to occur once per state change such as navigation, showing a SnackBar, showing a Dialog, etc..
listener is only called once for each state change (NOT including the initial state) unlike builder in BlocBuilder and is a void function.
If the bloc parameter is omitted, BlocListener will automatically perform a lookup using BlocProvider and the current BuildContext.
Only specify the cubit if you wish to provide a cubit that is otherwise not accessible via BlocProvider and the current BuildContext.
For fine-grained control over when the listener function is called an optional listenWhen can be provided. listenWhen takes the previous cubit state and current cubit state and returns a boolean. If listenWhen returns true, listener will be called with state. If listenWhen returns false, listener will not be called with state.
MultiBlocListener #
MultiBlocListener is a Flutter widget that merges multiple BlocListener widgets into one.MultiBlocListener improves the readability and eliminates the need to nest multiple BlocListeners.By using MultiBlocListener we can go from:
to:
Blocs 3 1 0 141
BlocConsumer #
BlocConsumer exposes a builder and listener in order react to new states. BlocConsumer is analogous to a nested BlocListener and BlocBuilder but reduces the amount of boilerplate needed. BlocConsumer should only be used when it is necessary to both rebuild UI and execute other reactions to state changes in the cubit. BlocConsumer takes a required BlocWidgetBuilder and BlocWidgetListener and an optional cubit, BlocBuilderCondition, and BlocListenerCondition.
If the cubit parameter is omitted, BlocConsumer will automatically perform a lookup usingBlocProvider and the current BuildContext.
An optional listenWhen and buildWhen can be implemented for more granular control over when listener and builder are called. The listenWhen and buildWhen will be invoked on each cubitstate change. They each take the previous state and current state and must return a bool which determines whether or not the builder and/or listener function will be invoked. The previous state will be initialized to the state of the cubit when the BlocConsumer is initialized. listenWhen and buildWhen are optional and if they aren't implemented, they will default to true.
RepositoryProvider #
RepositoryProvider is a Flutter widget which provides a repository to its children via RepositoryProvider.of(context). It is used as a dependency injection (DI) widget so that a single instance of a repository can be provided to multiple widgets within a subtree. BlocProvider should be used to provide blocs whereas RepositoryProvider should only be used for repositories.
Adobe xd windows 7. then from ChildA we can retrieve the Repository instance with:
MultiRepositoryProvider #
MultiRepositoryProvider is a Flutter widget that merges multiple RepositoryProvider widgets into one.MultiRepositoryProvider improves the readability and eliminates the need to nest multiple RepositoryProvider.By using MultiRepositoryProvider we can go from:
to:
Gallery #
Examples #
- Counter - an example of how to create a
CounterBlocto implement the classic Flutter Counter app. - Form Validation - an example of how to use the
blocandflutter_blocpackages to implement form validation. - Bloc with Stream - an example of how to hook up a
blocto aStreamand update the UI in response to data from theStream. - Complex List - an example of how to manage a list of items and asynchronously delete items one at a time using
blocandflutter_bloc. - Infinite List - an example of how to use the
blocandflutter_blocpackages to implement an infinite scrolling list. - Login Flow - an example of how to use the
blocandflutter_blocpackages to implement a Login Flow. - Firebase Login - an example of how to use the
blocandflutter_blocpackages to implement login via Firebase. - Github Search - an example of how to create a Github Search Application using the
blocandflutter_blocpackages. - Weather - an example of how to create a Weather Application using the
blocandflutter_blocpackages. The app uses aRefreshIndicatorto implement 'pull-to-refresh' as well as dynamic theming. - Todos - an example of how to create a Todos Application using the
blocandflutter_blocpackages. - Timer - an example of how to create a Timer using the
blocandflutter_blocpackages. - Firestore Todos - an example of how to create a Todos Application using the
blocandflutter_blocpackages that integrates with cloud firestore. - Shopping Cart - an example of how to create a Shopping Cart Application using the
blocandflutter_blocpackages based on flutter samples. - Dynamic Form - an example of how to use the
blocandflutter_blocpackages to implement a dynamic form which pulls data from a repository. - Wizard - an example of how to build a multi-step wizard using the
blocandflutter_blocpackages. - GraphQL - an example of how to use the
blocandflutter_blocpackages withgraphqlto retrieve data from api.graphql.jobs. - Fluttersaurus - an example of how to use the
blocandflutter_blocpackages to create a thesuarus app -- made for Bytconf Flutter 2020.
Dart Versions #
- Dart 2: >= 2.6.0
Maintainers #
A dart package that helps implement the BLoC pattern.
Learn more at bloclibrary.dev!
This package is built to work with:
Overview #
The goal of this package is to make it easy to implement the BLoC Design Pattern (Business Logic Component).
This design pattern helps to separate presentation from business logic. Following the BLoC pattern facilitates testability and reusability. This package abstracts reactive aspects of the pattern allowing developers to focus on writing the business logic.
Cubit #
A Cubit is the base for Bloc (in other words Bloc extends Cubit). Cubit is a special type of Stream which can be extended to manage any type of state. Cubit requires an initial state which will be the state before emit has been called. The current state of a cubit can be accessed via the state getter and the state of the cubit can be updated by calling emit with a new state.
State changes in cubit begin with predefined function calls which can use the emit method to output new states. onChange is called on each state change and contains the current and next state.
Creating a Cubit
Using a Cubit
Observing a Cubit
onChange can be overridden to observe state changes for a single cubit.
onError can be overridden to observe errors for a single cubit.
BlocObserver can be used to observe all cubits.
Bloc #
A Bloc is a more advanced type of Cubit which relies on events to trigger state changes rather than functions. Bloc extends Cubit which means it has the same public API as Cubit. However, rather than calling a function on a Bloc and directly emitting a new state, Blocs receive events and convert the incoming events into outgoing states.
State changes in bloc begin when events are added which triggers onEvent. The events are then funnelled through transformEvents. By default, transformEvents uses asyncExpand to ensure each event is processed in the order it was added but it can be overridden to manipulate the incoming event stream. mapEventToState is then invoked with the transformed events and is responsible for yielding states in response to the incoming events. transitions are then funnelled through transformTransitions which can be overridden to manipulation the outgoing state changes. Lastly, onTransition is called just before the state is updated and contains the current state, event, and next state.
Creating a Bloc
Using a Bloc
Observing a Bloc
Since all Blocs are Cubits, onChange and onError can be overridden in a Bloc as well.
In addition, Blocs can also override onEvent and onTransition.
Blocs 3 1 0 10
onEvent is called any time a new event is added to the Bloc.
onTransition is similar to onChange, however, it contains the event which triggered the state change in addition to the currentState and nextState.
BlocObserver can be used to observe all blocs as well.
Dart Versions #
- Dart 2: >= 2.6.0
Examples #
- Counter - an example of how to create a
CounterBlocin a pure Dart app.
Blocs 3 1 0 100
Maintainers #
Blocs 3 1 0 1 Sezonas
Supporters #
