Introduction:
Flutter is a single codebase, free, and open-source framework that allows developers to build beautiful, natively-compiled applications for mobile (Android & iOS), web, and desktop (Windows & Linux). Developed by Google, Flutter was first published in 2017 and has since become a favorite among developers and users. In this blog post, I will explain what Flutter is, how it works, its benefits, and its pros & cons, along with some examples and market stats from 2020.
What is Flutter?
Flutter is a Software Development Kit (SDK) that comes with all the tools and libraries needed to build User Interfaces (UIs) using a single codebase. Flutter uses a declarative and reactive UI approach, meaning the state of your application is represented in functions and updates automatically when the value changes. Unlike other modern UI toolkits and frameworks, Flutter has a different paradigm; it does not require an OEM app or WebView to render interactive widgets. Instead, it uses Skia, its proprietary rendering engine, which renders widget views on the screen, giving clear control over the appearance.
Dart is the programming language used to write your application logic and UI code in Flutter. Dart is an object-oriented, class-defined language with a C-style syntax that can optionally be transcompiled into JavaScript. Flutter, in its latest stable release, has the capability to be transpiled to JavaScript via Dart for web support.
What Suits You the Best is Flutter?
Some of the advantages that Flutter provides developers and users are:
- Flutter is cross-platform, meaning that a single codebase leads to competent and reliable performance of the UI across all platforms. This minimizes development cost, development time, and even the effort required for maintenance and complexity.
- Hot reload & hot restart: Flutter supports a feature called Hot Reload, which can be considered similar to live change asynchronous methods in the development process, where developers can test and debug their apps without losing the app's entire current state. Hot reload makes code changes in just a few seconds to the running app, and hot restart also does this within 2–3 seconds by resetting/clearing everything from the current state.
- Rich and expressive UI: Flutter offers a wide collection of widgets that act as the basic building blocks for constructing beautiful app designs. The widgets are composable, adaptive, and customizable, and they can be combined with each other, making them suitable for different platforms or screen sizes. Flutter also supports animations, transitions, gestures, accessibility, and internationalization features to provide a better UI experience.
- Performance: Flutter delivers high performance in UI through its rendering engine and native code compilation features. Additionally, Flutter employs a layered architecture that abstracts the UI from platform design imperatives, optimizing UI production across every possible platform and device. Flutter even has stateful hot reload, which maintains the app's state and makes all-dependent refactoring faster than ever.
Cons of Flutter
Of course, Flutter has a couple of challenges and limitations too, such as:
- Dart programming: Flutter only uses Dart, meaning you need to develop your mobile application using this language. Another drawback is that the mental model for building UIs in other frameworks is different from how you do it with Flutter, so developers have to adjust their thinking and skills accordingly.
- No native features: You can't access some platform-dependent functionalities and services like camera, Bluetooth, GPS, etc., directly from Flutter. These features can only be accessed via plugins or platform channels, which enable developers to communicate with native code. This can create issues such as compatibility, performance, and security problems.
- Limited web and desktop support: For both, Flutter is still in beta stage, and its features aren't as fully developed as those for mobile devices. Certain functionalities cannot be implemented natively, such as downloading files, copying and pasting from one field, or creating right-click menus/browser extensions. Support for these features has taken away an important piece of interactivity that was previously available. Many important features are not being added, such as support for keyboard shortcuts and window resizing/drag & drop in C++/Dart ffi engines.
How is Flutter Used?
There are a number of types of applications that can be built using Flutter according to different needs and domains, such as:
- Social media: With Flutter, you can build interactive and beautiful UIs for social media apps like Instagram, TikTok, Facebook, Twitter, etc.
- E-commerce: You can recreate platforms like Alibaba, Flipkart, eBay, or even Amazon using Flutter to create responsive UI-based e-commerce applications.
- Education: Applications like Duolingo, Khan Academy, Coursera, and Udemy can be built using Flutter by making their UIs interesting for users with dashboards, graphics, or adaptive User Interfaces.
- Media (News/Entertainment): Flutter is ideal for creating media applications with immersive and dynamic UIs like Netflix, Spotify, YouTube, or Twitch.
Statistics on Flutter
Some stats to show the growth in popularity and adoption of Flutter:
- GitHub stars: Flutter has more than 150,000 stars on GitHub, making it one of the most starred repositories across all fields.
- Stack Overflow questions: Flutter is one of the most searched topics on Stack Overflow, with over 120,000 questions.
- Google Trends: Flutter search interest has been consistently rising, hitting its highest point around March 2021.
- App Downloads: Flutter has powered over 2 million apps downloaded from the Google Play Store, making it one of the most popular developer tools.
- User Satisfaction: Flutter has a rating of 4.6/5 based on over a thousand reviews.
React Native is another cross-platform development framework that uses JavaScript and React to create UI. React Native uses the native UI components of the platforms to render the UI, while Flutter uses its own custom rendering engine to draw the UI . React Native relies on a JavaScript bridge to communicate with the native code, while Flutter uses native code compilation to run the app . React Native has a larger and more mature community and ecosystem, while Flutter has a faster and more expressive UI development .
There are many resources and courses available online to learn Flutter, such as:
- The official Flutter website, which provides documentation, tutorials, samples, and guides for Flutter development.
- The official Flutter YouTube channel, which provides videos, webinars, podcasts, and live events for Flutter development.
- The official Flutter Medium publication, which provides articles, stories, tips, and news for Flutter development.
- The official Flutter Udacity course, which provides a free and comprehensive course for Flutter development.
- The official Flutter codelabs, which provide hands-on exercises and projects for Flutter development.
Flutter is an open-source project that welcomes contributions from anyone who is interested in improving and enhancing the framework. You can contribute to Flutter by:
- Reporting bugs, issues, and feature requests on the Flutter GitHub repository.
- Submitting pull requests, code reviews, and patches on the Flutter GitHub repository.
- Writing tests, documentation, and tutorials for the Flutter website.
- Creating plugins, packages, and widgets for the Flutter pub.dev.
- Joining the Flutter community and participating in discussions, events, and surveys.
Flutter provides a variety of tools and features to help you test and debug your app, such as:
- The Flutter DevTools, which are a set of web-based tools that allow you to inspect, profile, and debug your app. You can access the Flutter DevTools from the command line, the IDE, or the browser.
- The Flutter Testing Framework, which is a set of libraries and tools that enable you to write unit, widget, and integration tests for your app. You can run the tests from the command line, the IDE, or the browser.
- The Flutter Driver, which is a tool that allows you to automate the testing of your app on real devices or simulators. You can use the Flutter Driver to perform end-to-end tests, performance tests, and screenshot tests.
- The Flutter Error Widget, which is a widget that displays a red screen with an error message and a stack trace when your app encounters an exception. You can also use the Flutter Error Banner, which is a banner that displays a brief error message at the top of the screen.
Flutter is designed to deliver high performance for your app, but there are some best practices and tips that you can follow to improve the performance further, such as:
- Use const and final keywords to declare constant and immutable variables, which can reduce memory allocation and garbage collection.
- Use keys to identify and reuse widgets that have the same type and state, which can reduce widget rebuilding and rendering.
- Use builders and lazily loaded widgets to create widgets on demand, which can reduce memory usage and loading time.
- Use custom painters and custom clips to draw and clip widgets that have complex shapes or effects, which can reduce widget composition and rendering.
- Use profile mode and release mode to measure and optimize the performance of your app. Profile mode enables performance metrics and debugging tools, while release mode disables them and enables code optimization.
Flutter supports accessibility and inclusion features that make your app more usable and friendly for everyone, such as:
- The Semantics widget, which is a widget that provides semantic information and actions for your app. You can use the Semantics widget to describe the meaning, role, and state of your widgets, as well as the actions that they can perform.
- The Accessibility Inspector, which is a tool that allows you to inspect and debug the accessibility of your app. You can use the Accessibility Inspector to check the semantic tree, the accessibility labels, the focus order, and the contrast ratio of your app.
- The TextScaleFactor, which is a property that controls the size of the text in your app. You can use the TextScaleFactor to adjust the text size according to the user’s preference and device settings.
- The MediaQueryData, which is a class that provides information about the device and the user. You can use the MediaQueryData to adapt your app to different screen sizes, orientations, brightness levels, and text directions.
Conclusion
Flutter is a modern and innovative framework for creating beautiful, natively compiled applications for mobile (Android & iOS) from the same codebase. While it has both advantages and disadvantages, Flutter can be employed in various use cases and domains. Flutter is rapidly growing in popularity, and it already has a huge community. You can look up all the resources and courses mentioned above to gain more knowledge on Flutter. Thank you for reading, and happy coding!
