deCompose.Delegate.Maintain

Managing complex UIs in Android often leads to bloated ViewModels with a growing maintenance cost. In this talk, I’ll show how we tackled this challenge in a large-scale, multi-module production app by introducing ViewModel Delegates, a modular approach to decompose features into smaller, focused components while keeping lifecycle safety, state management, and Compose integration intact. I’ll also cover how we approached testing delegates effectively and making tests scale, ensuring they remain reliable, fast, and reusable across modules.

With this approach, we reduced one of our heaviest ViewModels from 4,000 to 450 lines while making the codebase more modular and testable.

This 30 minute session is aimed at mid- to senior-level Android developers building multi-module apps for Android.

Attendees will leave with:
• A concrete pattern for splitting complex ViewModels using delegation.
• Best practices for testing delegates — from deterministic coroutine tests and Flow assertions to using fakes, and how to leverage testFixtures to share these test implementations across modules for maximum reusability.
• Lessons learned from applying these techniques in a real-world, large-scale app.