Architecture design patterns

When building user experiences, the perception of performance is sometimes just as important as the actual performance of the code. In general, users don’t like waiting for an action to finish to see the result, and anything that takes more than a few milliseconds could be considered “slow” or “unresponsive” from the user’s perspective.

Developers can help mitigate this negative perception by presenting a successful UI state before the background task is fully completed. An example of this would be tapping a “Subscribe” button, and seeing it change to “Subscribed” instantly, even if the background call to the... Read full article

Most Flutter applications, no matter how small or big they are, require storing data on the user’s device at some point, such as API keys, user preferences or data that should be available offline.

In this recipe, you will learn how to integrate persistent storage for key-value data in a Flutter application that uses the recommended Flutter architecture design. If you aren’t familiar with storing data to disk at all, you can read the Store key-value data on disk recipe.

Key-value stores are often used for saving simple data, such as app configuration, and in this... Read full article

Most Flutter applications, no matter how small or big they are, might require storing data on the user’s device at some point. For example, API keys, user preferences or data that should be available offline.

In this recipe, you will learn how to integrate persistent storage for complex data using SQL in a Flutter application following the Flutter Architecture design pattern.

To learn how to store simpler key-value data, take a look at the Cookbook recipe: Persistent storage architecture: Key-value data.

To read this recipe, you should be familiar with SQL and SQLite. If you need help,... Read full article

An offline-first application is an app capable of offering most or all of its functionality while being disconnected from the internet. Offline-first applications usually rely on stored data to offer users temporary access to data that would otherwise only be available online.

Some offline-first applications combine local and remote data seamlessly, while other applications inform the user when the application is using cached data. In the same way, some applications synchronize data in the background while others require the user to explicitly synchronize it. It all depends on the application requirements and the functionality it offers, and it’s... Read full article

Model-View-ViewModel (MVVM) is a design pattern that separates a feature of an application into three parts: the model, the view model and the view. Views and view models make up the UI layer of an application. Repositories and services represent the data layer of an application, or the model layer of MVVM.

A command is a class that wraps a method and helps to handle the different states of that method, such as running, complete, and error.

View models can use commands to handle interaction and run actions. As well, they can be used to display... Read full article

Dart provides a built-in error handling mechanism with the ability to throw and catch exceptions.

As mentioned in the Error handling documentation, Dart's exceptions are unhandled exceptions. This means that methods that throw exceptions don’t need to declare them, and calling methods aren't required to catch them either.

This can lead to situations where exceptions are not handled properly. In large projects, developers might forget to catch exceptions, and the different application layers and components could throw exceptions that aren’t documented. This can lead to errors and crashes.

In this guide, you will learn about this limitation... Read full article