Take your Flutter apps to the next level

Creating scalable apps that can move to market quickly and effectively is paramount in today's fast-paced world. Flutter and its underlying programming language, Dart, make creating apps that look good and feel natural on multiple platforms a reality.

Flutter is feature-packed. Its framework allows developers to build applications for Android, iOS, Linux, Fuschia, Windows and macOS from a single codebase. With Flutter, designers and developers can work together and move from Figma to app and deliver native experiences to users across platforms. Skilled Flutter developers can write the code for an app and run it on whatever platform they like in the same amount of time it would take to create an app for a single platform. This ability is helpful in today's fast-paced environment where scalability and reusability can be determining factors in an app's success.

Flutter is an open-source UI software development kit (SDK) created by Google to help developers build high-performance and cross-platform mobile, desktop and web applications. It’s designed to make development easier, providing teams with a framework, rendering engine and plenty of components to work with and tools to use. Providing its own rendering engine is a big advantage of Flutter and one of the reasons why some developers prefer it.

Its single codebase can help organizations save time and money depending on how the codebase is used. This approach is considered a code multiplier — especially for small development teams — since it can speed up the time to market and cut costs. It also helps developers build apps that are fast and responsive by using its own rendering engine as an interface between native code and the components designers and developers use to develop apps.

Frameworks like Flutter enable native app development for teams of all sizes. Some developers enjoy the ease of working with a single codebase since it allows them to build for multiple platforms in less time and might have less complexity than working with more than one codebase. A single codebase can also provide satisfactory consistency across the board when building an app for multiple platforms. As a result, app development, maintenance and testing throughout the development lifecycle is simplified and can demand less of a developer’s focus.

Flutter offers a number of benefits, including:

• Native speed: As mentioned, one of the biggest advantages of Flutter is its rendering engine. Whereas some cross-platform tools use WebView or native rendering to render content, Flutter renders the app itself instead of the platform and doesn’t require a bridge or context switch to operate between the two. Flutter’s rendering pipeline is also easy to use. Overall, the rendering engine helps improve the application’s speed and responsiveness in meaningful ways. When these are your priorities, Flutter is a compelling option.

• Open source: Flutter is an open-source toolkit, making it completely free to developers. There are no license fees and all upgrades are included.

• Dart programming language: Developers use Dart, a general-purpose object-oriented programming language, to code their Flutter applications. While Dart is an object-oriented language, it can still support some functional programming and functional programming concepts for those interested.

• Google-backed: Flutter is supported by Google, making it accessible to developers already familiar with Dart or C-style syntax and easier to integrate with Google’s other technologies.

• Cross-platform compatibility: Flutter is available as a fast, reliable cross-platform development toolkit. Teams can build native apps using Dart with the compilers targeting the different platforms for back-end and front-end development. You can also access native languages like Java and Swift for Android and iOS development, respectively.

• Faster development: Flutter has a hot reload feature that allows users to view changes to code without refreshing the application. While this has become less of an advantage over time, it can still save time during development.

• Community: Flutter’s active community of developers has contributed over 30,000 free packages since its release in 2017 — that’s a lot of support you can turn to whenever you need it.

Cross-platform development toolkits like Flutter can make it easy for developers to work directly with designs and design components. The process of recreating even the most complex design component is made easier through a combination of tools available on the Flutter framework, including layout tools, widgets inspired by React and packages on pub.dev, which is the Google-supported repository for Flutter add-ons. For example, there are tools that translate Figma or Adobe XD designs to code snippets written in Dart that developers can copy and use.

If a developer prefers to design bespoke UI elements, they can also individually control every pixel on the screen. While this functionality gives them more control, it also makes reproducing some native widgets more difficult than other cross-platform tools. And while the widgets are polished, it’s important to note that they don't necessarily mimic the different platforms very well.

Developers considering Flutter for cross-platform development need to weigh the tradeoff between the desire to develop cross-platform apps that behave exactly like native applications and the importance of speed and complexity. Flutter is fast; its single codebase also means a developer can avoid working in multiple codebases. However, when new features become available on either iOS or Android, there’s a lag between when a new native feature is available and when you can actually use it on Flutter. This isn’t just an issue with Flutter — it’s something all cross-platform tools deal with. But as a result, it’s unlikely that a Flutter app will behave 100% like a native app. 

Can you live with 99%?

If so, you’re in good company. A team of motivated developers can develop anything from enterprise apps to Google’s own Nest interface.

Developers put a lot of work into streamlining navigation since it has such an impact on user experience. While designing navigation for multiple platforms is certainly challenging,  Flutter has features and capabilities to address challenges that may come up and support engineers during development and testing. For example, developers can create a navigation drawer within the application and use a stateful widget that changes the content the user wants to see without having them navigate away and enter a new page.

As you know, mobile apps use routes to go from screen to screen as users navigate the program. Designing navigation on mobile devices is especially difficult since there are so many screen sizes and platforms to accommodate. There's also the risk of users getting lost in the UI or overwhelmed with scattered options when navigating the app.

If you ever face this problem, consider this solution: Use a navigation drawer with three display options, depending on the size of the screen. For example, the smallest size screen displays a simple hamburger menu on the top left side that users can press, opening the navigation drawer. On the other hand, the largest-width screen displays a completely open drawer with all menu selections available. While this is possible with other cross-platform tools, it’s how Flutter implements state management to incorporate this approach that makes it a unique and at times compelling option for cross-platform development. 

Currently, there are more than 30 packages for implementing state management available. The BLoC (business logic component) pattern is one of the most popular design patterns in Flutter to manage state, allowing devs to separate the UI from the business logic. 

Here’s how it works. The application’s presentation layer renders the UI, which the user interacts with, and the UI sends events to the BLoC. The BLoC receives the events, processes them and emits new states. The app’s repository then fetches and stores the data. 

Developers can use BLoC to add state to the entire screen, setting up simple menu choices to trigger screen changes without having to use routing structures that keep the user anchored to the navigation drawer.

At times, the effort required from developers to obtain the perfect look for their app is both time-consuming and frustrating. Typically, this process requires developers to compile and relaunch an application over and over again while making continuous, incremental adjustments. Flutter avoids this by using hot reloading, a feature that allows developers to make code changes and immediately see them reflected in an emulator. This enables developers to stay on the same screen while maintaining the state.

While there are alternatives to hot reloading, particularly Xcode previews and playgrounds in iOS, the functionality remains a useful tool.

To get started, here are a few high-level techniques to consider using in conjunction with the Flutter framework.

• State management: Flutter offers its own state management system utilizing inherited widgets, listenable and stream builders and change notifiers.

• Access to Firebase: The Flutter framework gives access to Google’s Firebase, including Firestore, Google’s NoSQL database, storage, analytics and authentication. This allows developers to create more resilient apps with global coverage.

• Testing and debugging programmatically: Developers can perform unit testing, integration testing, widget and performance testing and debugging without having to rely on user inputs. The testing can be done entirely in the source code. For example, unit tests can confirm the behavior of specific functions and widget tests can check the function of Flutter widgets without running the app.

Since the release of Flutter in 2019, Flutter has continued to increase its active user base, with Google claiming over 500,000 monthly users and the creation of more than a million apps.

Organizations of all sizes use Flutter during cross-platform development. Examples of enterprise companies using Flutter include:

• eBay's Motors app

• BMW's MyBMW app

• Groupon's mobile app

• The Hamilton Musical's official app

• Alibaba's Xianyu app

• ByteDance's short-form video app, CapCut

The high level of responsiveness that Flutter achieves with its rendering engine makes it less clunky than some cross-platform tools that use WebView or native rendering. While there are other alternatives such as React Native and Cordova, Flutter's rendering engine, framework, and tools built by its community make it worthy of consideration for cross-platform development. 

Flutter isn't done evolving, either. Google continues to develop new tools and features to improve it. For example, Google's release of a new graphics engine, Impeller, can help companies take their graphics to a whole new level. Beyond Flutter, the future of cross-platform development is bright as more tools emerge, evolve and expand their functionality.