Trendyol Nov 6, 2024

Jetpack Compose Performance

Article Summary

Hasan Kuşçu from Trendyol reveals why your Jetpack Compose app might be recomposing way more than it should. The culprit? Compose treats most classes as unstable by default.

This hands-on guide demonstrates how Jetpack Compose's recomposition behavior can silently tank your Android app's performance. Using Layout Inspector and real examples, the author shows how mutable collections and improper state management trigger unnecessary rebuilds.

Key Takeaways

Critical Insight

Two simple annotations can transform your Compose UI from constantly recomposing to efficiently skipping unchanged components.

The article includes a dramatic before/after comparison showing how a single annotation stopped an entire list from rebuilding on every switch toggle.

About This Article

Problem

Jetpack Compose treats classes with mutable collections like ArrayList as unstable by default. This causes the compiler to recreate these classes repeatedly during recomposition cycles.

Solution

Hasan Kuşçu shows how to add the @Stable annotation to data classes and move state managers outside of composables. This prevents unnecessary rebuilds.

Impact

The Layout Inspector showed a clear difference after applying @Stable. The ListCreator component stopped recomposing continuously and got skipped entirely. Only the switch button continued to recompose.