How to Easily Convert Your Existing App to Flutter?

Are you juggling between separate codebases for your iOS and Android apps, losing sleep over inconsistent UIs, and burning the midnight oil to push app updates? You can end all these dilemmas just by choosing to convert your existing apps to Flutter.

Flutter is a software development kit and UI framework from Google that aims to make developing beautiful mobile apps faster and easier. With Flutter, you can build modern, high-quality apps for Android, iOS, and future platforms using a unified codebase. Flutter apps run blazingly fast, look great and are fully functional on all major mobile platforms.

Google’s Flutter also has powerful developer tools, such as a code editor, interactive widgets, and performance profilers, that make it easy to build high-quality apps. In addition, Flutter offers unique functionality to help developers with the most mundane tasks.

So, Google has made it possible for companies to leverage Flutter with their existing native app without writing the whole codebase in Flutter all over again.

What does Converting your existing Android or iOS app to Flutter mean?

Flutter is Google’s brainchild and an open-source, cross-platform framework. It is highly flexible and allows developers to build a scalable, robust & fully functional cross-platform app. In the year 2019, Flutter released the add-to-app functionality. This functionality empowers us to embed the whole Flutter app or parts of the app into an existing iOS/Android app.

Simply put, you can migrate your iOS/Android app into Flutter seamlessly without compromising on performance. Even our team has leveraged this feature to convert an existing application to a Flutter app. And in this blog, we will be talking about Kody’s developed milk delivery application written in Android.

The application aims at satisfying the daily dairy needs of the customers. We formed a team of developers who worked vigorously to deliver a Flutter version of this application. Noteworthy, we didn’t do the transfer haphazardly; we deliberated the cases and then decided to convert to Flutter.

Why we choose Flutter is because of the following reasons:

• Its ease of development.
• The speed and performance of the Flutter-developed app.
• Two apps with a single code.
• The application needs to be tested only once.
• It is a modern framework providing all the required features & functionality for swift mobile app development.
• The Hot Reload feature allows us to instantly view the changes made in the source code.

You might have your own set of problems that you wish to solve using Flutter. So, discuss how they wish to proceed with the Flutter solution with your client and team.

Key Considerations Before Converting to Flutter for a Smoother Migration

Helping businesses make the most out of Flutter to develop an app from scratch and integrate it into existing ones, we have learned about common issues. Preparing for these potential issues in advance can save you significant time and effort, ensuring a smooth migration process.

Assess Your Current App’s Complexity

Start by evaluating the complexity of your existing app. Consider the number of features, third-party integrations, and the overall architecture. For instance, an app with a simple UI and minimal backend interactions will be easier to migrate than a complex application with extensive database interactions and custom animations.

Understanding this complexity will help you estimate the migration effort and resources required.

Understand Flutter’s Capabilities and Limitations

While Flutter is powerful, it’s essential to understand what it can and cannot do. Flutter excels at creating visually appealing, high-performance apps with a single codebase.

However, suppose your app relies heavily on platform-specific features or third-party libraries that don’t have Flutter support. In that case, you might need to find workarounds or consider how to integrate native code with your Flutter app.

Evaluate the Need for Custom Widgets

Flutter allows for the creation of custom widgets, which can be a double-edged sword. On the one hand, it offers the flexibility to design a unique UI/UX; on the other, it might require additional effort to replicate specific UI elements from your existing app.

Assess whether your app’s design can be easily adapted to Flutter’s material or Cupertino widgets or if you’ll need to invest time in custom widget development.

Plan for Integration Testing

Migrating to Flutter means you’ll have a single codebase for both iOS and Android, but it doesn’t eliminate the need for thorough testing on both platforms. Plan for integration testing to ensure your Flutter app performs well and provides a consistent user experience across devices.

The integration testing must include testing third-party integrations, push notifications, and platform-specific features.

Review Third-party Dependencies

Make a list of all third-party libraries, SDKs, and APIs your current app uses. Verify whether these dependencies are supported in Flutter or if equivalent packages are available in the Flutter ecosystem.

In cases where direct equivalents are unavailable, consider how you will handle these dependencies—whether by finding alternatives, using platform channels to integrate native code, or potentially contributing to the Flutter community by creating a new package.

Understand the Migration Impact on Your User Base

Consider how the migration will affect your existing user base. A well-executed migration to Flutter should be seamless for your users, offering them a better and more consistent experience across platforms.

However, it’s better to plan for any potential downtime, data migration issues, or changes in app behavior that could affect user satisfaction.

Hire experienced Flutter developers

Migrating your existing Android, iOS, or both apps to Flutter requires a team of experts who know Flutter inside out as well as native technologies. The development team must have command over the framework’s underlying programming language, Dart, its UI library, and other features. Here’s the guide for Flutter developer skills you must look out for to build a strong team.

How do you transfer your existing app into Flutter?

First of all, you need to hire good programmers. But if you are a CEO or CTO without tech experience, you take our in-depth guide on how to hire Flutter developers to avoid common mistakes. you need to integrate Flutter as a library or module. That module is responsible for reflecting the application’s UI. You can create a module using Flutter create-t module command. This will initiate a new project creation yet with a bit different structure.

By creating a module in this way, you can separate the main code from the Flutter code. This module acts as an external dependency.

Things that Flutter allows us to do when integrated into Android apps.

• You can add a Flutter SDK hook to your Gradle script to auto-build and import the Flutter module.
• If you want to integrate the Flutter module into your own build system, build your Flutter module into a generic Android Archive (AAR) that also better Jetifier interoperability with AndroidX.
• Use FlutterEngine API for starting and continuing your Flutter environment independently.
• Module import/creation wizard allows you to co-edit Android and Flutter projects in Android Studio.
• It supports apps built with Java and Kotlin.
• Flutter plugins can be integrated into the preexisting platform and used for Flutter modules to interact with the platform.
• Using the Flutter attach function from an IDE or the command line, you can connect to an app that contains Flutter and debug it or reload it using a stateful hot reload.

Add Flutter to an existing iOS app:

1. Open existing project
2. Create Flutter Module
3. CocoaPods Install
4. Use Flutter iOS APIs
5. Build & run
6. Attach & hot reload.

Things that Flutter allows us to do when integrated into iOS apps.

• Add a Flutter SDK hook to your CocoaPods and Xcode build phase to auto-build and import the Flutter module.
• It allows you to create a Flutter module into a generic iOS Framework so that you can integrate the module into your own build system.
• FlutterEngine API is for starting and persisting your Flutter environment independently of attaching a FlutterViewController.
• It also supports both types of iOS apps, Objective-C and Swift.
• Let Flutter modules use Flutter plugins to interact with the platform.
• Using the Flutter attach function from an IDE or the command line, you can connect to an app that contains Flutter and debug it or reload it using a stateful hot reload.

Originally published at https://kodytechnolab.com/blog/convert-existing-app-to-flutter/ on February 08, 2024.