flutter_redux 0.3.0

  • README.md
  • CHANGELOG.md
  • Example
  • Installing
  • Versions
  • 50

flutter_redux #

build status coverage report

A set of utilities that allow you to easily consume a Redux Store to build Flutter Widgets.

This package is built to work with Redux.dart. If you use Greencat, check out flutter_greencat.

Redux Widgets #

  • StoreProvider - The base Widget. It will pass the given Redux Store to all descendants that request it.
  • StoreBuilder - A descendant Widget that gets the Store from a StoreProvider and passes it to a Widget builder function.
  • StoreConnector - A descendant Widget that gets the Store from the nearest StoreProvider ancestor, converts the Store into a ViewModel with the given converter function, and passes the ViewModel to a builder function. Any time the Store emits a change event, the Widget will automatically be rebuilt. No need to manage subscriptions!

Usage #

Let's demo the basic usage with the all-time favorite: A counter example!

import 'package:flutter/material.dart';
import 'package:redux/redux.dart';
import 'package:flutter_redux/flutter_redux.dart';

// One simple action: Increment
enum Actions { Increment }

// The reducer, which takes the previous count and increments it in response
// to an Increment action.
int counterReducer(int state, action) {
  if (action == Actions.Increment) {
    return state + 1;
  }

  return state;
}

void main() {
  runApp(new FlutterReduxApp());
}

class FlutterReduxApp extends StatelessWidget {
  // Create your store as a final variable in a base Widget. This works better
  // with Hot Reload than creating it directly in the `build` function.
  final store = new Store(counterReducer, initialState: 0);

  @override
  Widget build(BuildContext context) {
    final title = 'Flutter Redux Demo';

    return new MaterialApp(
      theme: new ThemeData.dark(),
      title: title,
      home: new StoreProvider(
        // Pass the store to the StoreProvider. Any ancestor `StoreConnector`
        // Widgets will find and use this value as the `Store`.
        store: store,
        child: new Scaffold(
          appBar: new AppBar(
            title: new Text(title),
          ),
          body: new Center(
            child: new Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                new Text(
                  'You have pushed the button this many times:',
                ),
                // Connect the Store to a Text Widget that renders the current
                // count.
                //
                // We'll wrap the Text Widget in a `StoreConnector` Widget. The
                // `StoreConnector` will find the `Store` from the nearest
                // `StoreProvider` ancestor, convert it into a String of the
                // latest count, and pass that String  to the `builder` function
                // as the `count`.
                //
                // Every time the button is tapped, an action is dispatched and
                // run through the reducer. After the reducer updates the state,
                // the Widget will be automatically rebuilt with the latest
                // count. No need to manually manage subscriptions or Streams!
                new StoreConnector<int, String>(
                  converter: (store) => store.state.toString(),
                  builder: (context, count) => new Text(
                        count,
                        style: Theme.of(context).textTheme.display1,
                      ),
                )
              ],
            ),
          ),
          // Connect the Store to a FloatingActionButton. In this case, we'll
          // use the Store to build a callback that with dispatch an Increment
          // Action.
          //
          // Then, we'll pass this callback to the button's `onPressed` handler.
          floatingActionButton: new StoreConnector<int, VoidCallback>(
            converter: (store) {
              // Return a `VoidCallback`, which is a fancy name for a function
              // with no parameters. It only dispatches an Increment action.
              return () => store.dispatch(Actions.Increment);
            },
            builder: (context, callback) => new FloatingActionButton(
                  // Attach the `callback` to the `onPressed` attribute
                  onPressed: callback,
                  tooltip: 'Increment',
                  child: new Icon(Icons.add),
                ),
          ),
        ),
      ),
    );
  }
}

Purpose #

One question that reasonable people might ask: Why do you need all of this if StatefulWidget exists?

My advice is the same as the original Redux.JS author: If you've got a simple app, use the simplest thing possible. In Flutter, StatefulWidget is perfect for a simple counter app.

However, say you have more complex app, such as an E-commerce app with a Shopping Cart. The Shopping Cart should appear on multiple screens in your app and should be updated by many different types of Widgets on those different screens (An "Add Item to Cart" Widget on all your Product Screens, "Remove Item from Cart" Widget on the Shopping Cart Screen, "Change quantity" Widgets, etc).

Additionally, you definitely want to test this logic, as it's the core business logic to your app!

Now, in this case, you could create a Testable ShoppingCart class as a Singleton or Create a Root StatefulWidget that passes the ShoppingCartDown Down Down through your widget hierarchy to the "add to cart" or "remove from cart" Widgets .

Singletons can be problematic for testing, and Flutter doesn't have a great Dependency Injection library (such as Dagger2) just yet, so I'd prefer to avoid those.

Yet passing the ShoppingCart all over the place can get messy. It also means it's way harder to move that "Add to Item" button to a new location, b/c you'd need up update the Widgets throughout your app that passes the state down.

Furthermore, you'd need a way to Observe when the ShoppingCart Changes so you could rebuild your Widgets when it does (from an "Add" button to an "Added" button, as an example).

One way to handle it would be to simply setState every time the ShoppingCart changes in your Root Widget, but then your whole app below the RootWidget would be required to rebuild as well! Flutter is fast, but we should be smart about what we ask Flutter to rebuild!

Therefore, redux & redux_flutter was born for more complex stories like this one. It gives you a set of tools that allow your Widgets to dispatch actions in a naive way, then write the business logic in another place that will take those actions and update the ShoppingCart in a safe, testable way.

Even more, once the ShoppingCart has been updated in the Store, the Store will emit an onChange event. This lets you listen to Store updates and rebuild your UI in the right places when it changes! Now, you can separate your business logic from your UI logic in a testable, observable way, without having to Wire up a bunch of stuff yourself!

Similar patterns in Android are the MVP Pattern, or using Rx Observables to manage a View's state.

flutter_redux simply handles passing your Store down to all of your descendant StoreConnector Widgets. If your State emits a change event, only the StoreConnector Widgets and their descendants will be automatically rebuilt with the latest state of the Store!

This allows you to focus on what your app should look like and how it should work without thinking about all the glue code to hook everything together!

0.3.0 #

  • Make StoreProvider.of a factory rather than a static method
  • Additional documentation based on questions from the community

0.2.0 #

  • Update for Redux 2.0.0

0.1.1 #

  • Update documentation

0.1.0 #

Initial Version of the library.

  • Includes the ability to pass a Redux Store down to descendant Widgets using a StoreProvider.
  • Includes the StoreConnector and StoreBuilder Widgets that capture the Store from the StoreProvider and build a Widget in response.

example/lib/main.dart

import 'package:flutter/material.dart';
import 'package:redux/redux.dart';
import 'package:flutter_redux/flutter_redux.dart';

// One simple action: Increment
enum Actions { Increment }

// The reducer, which takes the previous count and increments it in response
// to an Increment action.
int counterReducer(int state, action) {
  if (action == Actions.Increment) {
    return state + 1;
  }

  return state;
}

void main() {
  runApp(new FlutterReduxApp());
}

class FlutterReduxApp extends StatelessWidget {
  // Create your store as a final variable in a base Widget. This works better
  // with Hot Reload than creating it directly in the `build` function.
  final store = new Store(counterReducer, initialState: 0);

  @override
  Widget build(BuildContext context) {
    final title = 'Flutter Redux Demo';

    return new MaterialApp(
      theme: new ThemeData.dark(),
      title: title,
      home: new StoreProvider(
        // Pass the store to the StoreProvider. Any ancestor `StoreConnector`
        // Widgets will find and use this value as the `Store`.
        store: store,
        child: new Scaffold(
          appBar: new AppBar(
            title: new Text(title),
          ),
          body: new Center(
            child: new Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                new Text(
                  'You have pushed the button this many times:',
                ),
                // Connect the Store to a Text Widget that renders the current
                // count.
                //
                // We'll wrap the Text Widget in a `StoreConnector` Widget. The
                // `StoreConnector` will find the `Store` from the nearest
                // `StoreProvider` ancestor, convert it into a String of the
                // latest count, and pass that String  to the `builder` function
                // as the `count`.
                //
                // Every time the button is tapped, an action is dispatched and
                // run through the reducer. After the reducer updates the state,
                // the Widget will be automatically rebuilt with the latest
                // count. No need to manually manage subscriptions or Streams!
                new StoreConnector<int, String>(
                  converter: (store) => store.state.toString(),
                  builder: (context, count) => new Text(
                        count,
                        style: Theme.of(context).textTheme.display1,
                      ),
                )
              ],
            ),
          ),
          // Connect the Store to a FloatingActionButton. In this case, we'll
          // use the Store to build a callback that with dispatch an Increment
          // Action.
          //
          // Then, we'll pass this callback to the button's `onPressed` handler.
          floatingActionButton: new StoreConnector<int, VoidCallback>(
            converter: (store) {
              // Return a `VoidCallback`, which is a fancy name for a function
              // with no parameters. It only dispatches an Increment action.
              return () => store.dispatch(Actions.Increment);
            },
            builder: (context, callback) => new FloatingActionButton(
                  // Attach the `callback` to the `onPressed` attribute
                  onPressed: callback,
                  tooltip: 'Increment',
                  child: new Icon(Icons.add),
                ),
          ),
        ),
      ),
    );
  }
}

Use this package as a library

1. Depend on it

Add this to your package's pubspec.yaml file:


dependencies:
  flutter_redux: ^0.3.0

2. Install it

You can install packages from the command line:

with pub:


$ pub get

with Flutter:


$ flutter packages get

Alternatively, your editor might support pub get or flutter packages get. Check the docs for your editor to learn more.

3. Import it

Now in your Dart code, you can use:


import 'package:flutter_redux/flutter_redux.dart';
  
Version Uploaded Documentation Archive
0.5.3 Jan 7, 2019 Go to the documentation of flutter_redux 0.5.3 Download flutter_redux 0.5.3 archive
0.5.2 Jun 19, 2018 Go to the documentation of flutter_redux 0.5.2 Download flutter_redux 0.5.2 archive
0.5.1 May 31, 2018 Go to the documentation of flutter_redux 0.5.1 Download flutter_redux 0.5.1 archive
0.5.0 Mar 30, 2018 Go to the documentation of flutter_redux 0.5.0 Download flutter_redux 0.5.0 archive
0.4.1 Mar 27, 2018 Go to the documentation of flutter_redux 0.4.1 Download flutter_redux 0.4.1 archive
0.4.0 Mar 20, 2018 Go to the documentation of flutter_redux 0.4.0 Download flutter_redux 0.4.0 archive
0.3.6 Mar 19, 2018 Go to the documentation of flutter_redux 0.3.6 Download flutter_redux 0.3.6 archive
0.3.5 Feb 14, 2018 Go to the documentation of flutter_redux 0.3.5 Download flutter_redux 0.3.5 archive
0.3.4 Nov 25, 2017 Go to the documentation of flutter_redux 0.3.4 Download flutter_redux 0.3.4 archive
0.3.3 Nov 25, 2017 Go to the documentation of flutter_redux 0.3.3 Download flutter_redux 0.3.3 archive

All 16 versions...

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Health:
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Overall:
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The package version is not analyzed, because it does not support Dart 2. Until this is resolved, the package will receive a health and maintenance score of 0.

Analysis issues and suggestions

Support Dart 2 in pubspec.yaml.

The SDK constraint in pubspec.yaml doesn't allow the Dart 2.0.0 release. For information about upgrading it to be Dart 2 compatible, please see https://www.dartlang.org/dart-2#migration.

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Make sure dartdoc successfully runs on your package's source files. (-10 points)

Dependencies were not resolved.