Flutter Redux: An Introduction to State Management Framework

Flutter is a popular framework for app development, but as you build more complex apps, you'll need to manage your app state.

In this tutorial, we'll take a look at Flutter Redux – a library that helps you manage your app state in a predictable way.

Getting Started with Flutter Redux

To get started with Flutter Redux, you need to add it to your dependencies in your pubspec.yaml file:

dependencies:
  flutter_redux: ^0.8.2



    Once you have added Flutter Redux to your dependencies, you can start using it in your app.


Defining Your Redux State


    The first thing you need to do when using Flutter Redux is define your state. Your state is represented by a simple class that contains the data that your app needs to function.



    For example, if you have an app that manages a list of todos, your state might look something like this:


class AppState {
  final List todos;
  
  AppState({this.todos});
}



    In this example, we have defined a simple state class that contains a list of todos.


Actions


    The next thing you need to do is define your actions. Actions are objects that describe something that has happened in your application.



    For example, an action might describe a user adding a todo to the list:


class AddTodoAction {
  final Todo todo;
  
  AddTodoAction(this.todo);
}



    In this example, we have defined an action class that contains a todo object.


Reducers


    The last thing you need to define before you can start using Flutter Redux is your reducer. The reducer is a function that takes in your current state and an action and returns a new state.



    For example, your reducer might look something like this:


AppState appReducer(AppState state, dynamic action) {
  if(action is AddTodoAction) {
    return AppState(
      todos: List.from(state.todos)..add(action.todo),
    );
  }
  
  return state;
}



    In this example, we have defined a simple reducer that handles the AddTodoAction. It takes in the current state and the action and returns a new state with the new todo added to the list.


Using Flutter Redux


    Now that you have defined your state, actions, and reducer, you can start using Flutter Redux in your app. The first thing you need to do is create a store.


final store = Store(
  appReducer,
  initialState: AppState(todos: []),
);



    In this example, we have defined a store with our appReducer and an initial state of an empty list of todos.



    Now that you have defined your store, you can start dispatching actions:


store.dispatch(AddTodoAction(todo));



    In this example, we are dispatching the AddTodoAction with a todo object.


Conclusion


    Flutter Redux is a powerful state management library that helps you manage your app state in a predictable way. By defining your state, actions, and reducers, you can easily keep track of your app's data and make changes to it in a reliable manner.