What is Flutter app?

The tech world has undergone a sea change in the past few years. Smartphones have enabled people to connect to the internet anytime and from anywhere, as long as there is a working internet connection. Consumers are flooded with mobile applications for any and everything. In recent years, app developers would have heard of something called a Flutter app. What is Flutter app? And why has it gotten so popular? Read this article to find out.

What is Flutter?

Flutter was introduced by Google in 2015 in its beta stage and then officially launched in 2018. It is a free open-source cross-platform software development kit (SDK) that developers can use to build both iOS and Android applications using the same code base. Flutter has a framework or User Interface (UI) library that houses a collection of reusable UI elements such as sliders, buttons, and so on, that can be personalised by developers. Over time, Flutter has gone from strength to strength and is considered to be among the top 11 software repositories as per Github stars. Flutter aims to allow developers to create high-quality and high-performance apps that work naturally and seamlessly across platforms, accepting changes wherever necessary while sharing the same code as much as possible. So a Flutter app is one that has been developed using the Flutter SDK.

Flutter app – An overview

Here is a broad overview of the features of Flutter apps:

1. Technical architecture:
   One advantage of Flutter is that it offers developers everything they need for app development within the Flutter engine itself. It is designed as a multi-layered expandable system. There are a series of independent libraries that are dependent on the underlying layer. Every layer is independent as well and does not have access to other layers below it. Every part of the technical architecture has been built in a way to be replaceable and elective. The flutter engine is composed of the Skia C++ engine, which is a 2D graphics rendering library.
   
   
2. Programming language:
   Flutter apps are made using a typed programming language called Dart, which was again created by Google in 2011. The focus of Fart is on front-end development and so developers use it to create web and mobile applications. Dart is compiled ahead of time (AOT) into the native code for different platforms which allow for a quick start-up time of the app. So a Flutter app will not have performance problems related to needing a JavaScript bridge. Moreover, Dart can also comply with just-in-time (JIT), which is extremely handy during the development phase of a flutter app. Dart uses an advanced garbage collection and allocation scheme that is very fast in allocating short-lived objects. This results in the flutter app having very smooth animation and scrolling.
   
   
3. Development API and UI:
   Flutter has a reactive UI framework where the developer provides the mapping from the application state to the interface state. The framework then updates the interface during the runtime when the application state is changed. The flutter framework comes with device API access, UI rendering components, stateful management, testing, and many libraries. As Flutter is bundled with this rich set of components, it removes the need for third-party libraries. In a Flutter app, widgets act as the building blocks of the app’s UI and are an entrenched part of the UI. Widgets have a hierarchy that is based on composition. So, a widget will nest inside its parent and receive context from the parent.  When there is an event (for example, user interaction), the app tells the framework to replace one widget in the hierarchy with another. The framework compares the old and new widgets and then updates the UI accordingly.
   
   
4. Hot reload:
   Flutter has the advantage of a Hot Reload feature that allows developers to build UIs, experiment, and fix bugs easily and quickly. When developing a flutter app, this feature allows developers to view any changes made due to the addition of app features, bug fixes, or building of the user interface, without needing to refresh the app continuously.
   
   
5. Community and testing support:
   Flutter has a robust and rapidly growing community and so, developers can confer with and support each other about building apps. Flutter also provides comprehensive testing support with plenty of features in order to test apps at all levels—widget, unit, as well as integration. Completely detailed documentation is provided in order to test the Flutter apps. Also, there is a testing feature of widget that developers can use by creating widget tests to evaluate the UI.

Benefits of Flutter

1. Cost and time efficiency:
   Developers can use the same code for building both iOS and Android apps. This cross-platform development saves time and resources throughout the process of app development.
   
   
2. Quick development and enhanced productivity:
   One reason why Flutter has gained traction is because of how easy it is to make and view changes. Thanks to the Hot Reload feature, developers can change their code and view it instantly. This speeds up app development, thereby, enhancing productivity.
   
   
3. Exceptional performance:
   Flutter’s Dart programming language compiles directly into native code. Moreover, Flutter uses its own widgets without the need for OEM widgets. These two factors help deliver an exceptional performance as they ensure quick start-up times and minimal performance issues.
   
   
4. Compatibility:
   Since Flutter has its own widgets for app development there are fewer compatibility issues to contend with. So app developers don’t encounter problems over different OS versions, nor have to spend as much time testing an app on older OS versions.
   
   
5. Open-source:
   Flutter has the advantage of being a free and open-source technology used by a vibrant community of developers who offer support, handy resources, and extensive documentation.

The bottom line

Today there are thousands of Flutter apps in app stores. The famous Alibaba group created a Flutter app called Xianyu with over 50 million users. The advantages Flutter brings to the table make it a formidable technology.  It is no wonder then that in a short space of a few years, Flutter has succeeded in becoming so popular with mobile app developers the world over.

Sources:

1. https://flutter.dev/docs/resources/architectural-overview
2. https://blog.codemagic.io/what-is-flutter-benefits-and-limitations/
3. https://medium.com/@concisesoftware/what-is-flutter-here-is-everything-you-should-know-faed3836253f
4. https://flutter.dev/docs/development/tools/hot-reload