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24 October 2022

ZEPETO plans to migrate at least 80% of the app’s UI to Jetpack Compose

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ZEPETO is a 3D social universe built by NAVER Z with more than 300 million users in over 200 countries. Those users can create unique avatars, foster friendships, and explore virtual realms of their own design. ZEPETO commits itself to creating spaces that prioritize the user’s experience. For its engineers, that meant making the switch to Jetpack Compose, Android’s modern toolkit for building native UI.ZEPETO plans to migrate at least 80% of the app's UI to Jetpack Compose

Embracing Jetpack Compose

ZEPETO was originally designed and developed using Views, Unity and OpenGL, but today 20% of the UI originally written in Views has been rewritten with Jetpack Compose. ZEPETO’s developers began to sequentially integrate the toolkit knowing it would resolve a number of recurring engineering friction points. With the Views system, implementing custom UI with some specific shapes, such as sliders or switches, required implementing the onDraw method with a Canvas. Jetpack Compose allows ZEPETO’s developers to implement these types of UI in Kotlin without needing to implement custom classes, simplifying the process and eliminating the extra steps required.

Cleaning up the codebase

With Jetpack Compose, ZEPETO’s developers rewrote complex UI features. They built a design system that helped organize fonts and sizes in a more intuitive way, improving maintainability, efficiency, and the UX. “Using Compose, we rewrote parts of the app where the UI is relatively complex and various business logics exist, such as the character shop, gift giving, and face decoration,” said Android Developer Hojung Kim. In places like the pager and grid areas of the character shop, Composable functions helped reduce the amount of code by more than 10%.

The ZEPETO team decided to migrate its common dialog components to Compose too. This enabled its engineers to use the desired type of dialog needed throughout all parts of the app. “Each element of the common dialog can now be made into a component, making it possible to create a common dialog, just like assembling a Lego,” said Juhyung Park, Android Developer at ZEPETO. Modularizing the code allowed the engineers to implement commonly used app components much faster than before. By migrating these dialog components, the team was able to clean up 1600+ lines of code, making it much more readable, understandable, and significantly easier to maintain.

Refining the developer experience

Jetpack Compose drastically increased the efficiency of previewing, developing, and implementing UI by allowing developers to reuse and share UI elements. ZEPETO developers have already created more than 230 preview functions to effortlessly test and debug features across the application.

It was also relatively easy for the team to learn how to use Jetpack Compose. “It doesn’t take long for developers familiar with the existing Android View system to reach a level where they can use Compose in actual practice,” said Hojung.

We rewrote the Character Shop feature in Compose. It was much faster to write it in Compose, and we reduced the amount of code by over 10% ≫
Hojung Kim Android developer, ZEPETO

Moving forward with Compose

The ZEPETO team is motivated by Google’s increasing support for Jetpack Compose as it’s clear Compose is a huge priority for Google. They’re excited about how Google is integrating more Android APIs with Compose, and are looking forward to further development of the toolkit.

Several of ZEPETO’s features are now built with Jetpack Compose alongside the graphics built with Unity and OpenGL, such as the character shop, video and photo editors, and dialog components, but the team doesn’t plan to stop there. Given the improvements they’ve seen with development speed, code maintenance, and code reduction, they’ll continue migrating existing screens and building new features with Compose. “In the long run,” finished Hojung, “more than 80% of the UI will be written with Compose,” with the remaining UI and graphics with Unity and OpenGL.

Optimize your app

Learn how you can upgrade your UI development with Jetpack Compose.