Android Non-Transitive R Class Migration

3 posts · Jan 2018 – Feb 2023

What this trail covers

This thread tracks the evolution of Slack's Android build system, focusing on optimizing build times and APK size. Initial posts detailed the Duplo modularization effort and the migration to non-transitive R classes. This post details the extension of Anvil's code generation capabilities to automatically generate Dagger wiring code for Activities, reducing boilerplate and eliminating kapt dependencies. This further improves build times and developer experience.

All Slack trails

Feb 2023It’s a non-transitive R class worldThis post details the migration of Slack's Android codebase to use non-transitive R classes. It outlines the challenges of referencing resources, establishes conventions for Kotlin (import aliases) and Java (fully-qualified names), and describes a chosen migration strategy that involved find-and-replace operations and scripting due to the scale of the codebase. It also covers developer experience enhancements like live templates and custom lint checks for convention enforcement. The migration yielded a ~14% improvement in incremental build times and an ~8.5% reduction in APK/DEX size.
Jul 2021Extending Anvil for Fun and ProfitThis post details the extension of Anvil's compiler API to automatically generate Dagger wiring code for Activities. It introduces a custom `CodeGenerator` that hooks into the compiler to detect `@InjectWith` annotations and generate `AnvilInjector` and `InjectorBinder` classes. This eliminates manual boilerplate for Activity injection and removes the need for `dagger-android-processor` and kapt for this specific use case, further reducing build times.
Jan 2018Android UI Automation: Part 1, Building TrustThis post details the extension of Anvil's code generation capabilities to automatically generate Dagger wiring code for Activities, reducing boilerplate and eliminating kapt dependencies, further improving build times and developer experience.
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