Mastering Android APK Size: Youku’s 5‑Year Package Slimming Journey

Five‑Year Governance Review

Since 2017 Youku has invested five years in Android APK size governance, moving from a chaotic growth phase to a sustainable, low‑cost maintenance model. The effort is divided into three special‑governance periods and two continuous‑governance periods.

1.1 Special Governance (2017‑2018)

Technical means: offline unused modules, remote‑bundle, image compression & vectorization.

Strategy: single‑point refactoring of major issues.

Organization: small, loosely‑coupled team.

1.2 Continuous Governance (2020‑present)

Focus on precise analysis, tooling, and distributed responsibility.

All client teams participate, shifting from a "center‑heavy" to a "PVP" collaborative model.

Key tools: franky plugin, CLI analyzer, and size‑gate platform.

Governance Modes

The two modes are Special‑type (short‑term, rapid shrink) and Normal‑type (long‑term, steady reduction). Special‑type achieves quick wins but often rebounds; Normal‑type integrates size control into daily development like stability and performance.

Technical Support

Accurate byte‑level size measurement is the foundation. It includes four steps: measurement, guidance, evaluation, and responsibility attribution . The core tool franky provides:

Element‑level real size in the APK.

Aggregation to modules, features, business, and teams.

Detection of nine slim‑item categories (unused classes, un‑obfuscated classes, oversized resources, duplicate resources, multi‑dimensional resources, transparent PNGs, similar resources, non‑standard STL usage, unused export symbols).

Slimming Techniques

Techniques are grouped into three categories:

Remote‑ization : move code, bundles, or resources to the server (remote‑so, remote‑bundle, remote‑resource).

Whole‑Package Slimming : Proguard/R8, D8, R‑class merging, Dex layout optimization, byte‑code instruction reduction, resource shrinking, image compression, resources.arsc compression, duplicate removal, resource obfuscation, debug‑symbol stripping, ABI splitting, 7z compression.

Single‑Point Slimming : address each slim‑item directly in source code (e.g., remove unused classes, delete oversized resources, clean up duplicate assets).

Future Directions

Continued exploration is needed for deeper SO analysis, smarter Proguard rule assistance, and better library design. Emerging AndroidX components and vendor SDKs will bring new challenges and opportunities for further size reduction.

Key Diagrams