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Learn how to seamlessly update your Flutter app's item list based on changes in item status using the Provider package.
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This video is based on the question https://stackoverflow.com/q/62865729/ asked by the user 'Andrei' ( https://stackoverflow.com/u/11524193/ ) and on the answer https://stackoverflow.com/a/62868763/ provided by the user 'EdwynZN' ( https://stackoverflow.com/u/3547212/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Update Your Item List Dynamically with Flutter and Provider

Managing the state of your Flutter application can sometimes feel daunting, especially when it comes to updating lists based on interactivity. A common scenario developers face is needing to refresh a list when an item's status changes. In this post, we'll explore how to elegantly update a list of favorite items in a Flutter app using the Provider package.

The Scenario

Imagine you have a list of items, each with a "favorite" status. When a user toggles the favorite status of an item, you'd like your application's UI to reflect this change by updating the displayed list of favorite items.

You might have stumbled upon some challenges when trying to implement this functionality. For instance, using ChangeNotifierProxyProvider didn't work as expected, where the status changed but fail to notify the main list.

Instead of relying on methods that clutter the code, let’s examine a structured solution that leverages Provider efficiently.

Understanding the Structure

Before we dive into the solution, let’s break down the roles of different classes involved in managing the item states effectively:

Collection: This class holds the list of items and manages the favorite status logic.

Items: A simple model representing each item.

MyHomePage: This widget builds the UI and listens for updates in the favorite list.

CardWidget: Displays each individual item and allows the user to toggle its favorite status.

Solution Breakdown

Step 1: Update the Collection Class

The first step is to ensure the favorite status logic resides solely in the Collection class, preventing tighter coupling between Items and Collection. Here’s a modification of the original Collection class:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Modify the Items Class

The Items class should remain a simple model, retaining only the necessary properties:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Update MyHomePage Widget

We need to ensure that our UI updates properly whenever the list changes. Using context.select will help monitor specific parts of the state. Here's how to implement it:

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Adapting the CardWidget

The CardWidget will now interact with the Collection class to toggle the favorite status:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By structuring your app this way, you're achieving a clean separation of concerns. The Collection class is responsible for managing the list and maintaining state, while the Items class remains a lightweight model. Using the Provider effectively allows your UI to reflect changes in data seamlessly without bloating your code with unnecessary setState calls.

In summary, this method not only simplifies your code but also ensures better maintainability as your application grows. Happy coding with Flutter!