※Notes記事では、英語のセッション動画やポッドキャストの内容を(雑に)英語でメモに書き残すことを行っています。本記事は、あくまで動画を見ながら、参考程度に読んでいただくことを想定しています。Notes記事には雑メモ程度のものだったり、書き起こしのようなものもあります。これから実際の動画を見る際には、本記事の内容が少しでもお役に立てば幸いです。（内容において不備、誤字脱字等ありましたら気軽にご連絡いただけると嬉しいです！m(__)m)
本記事は、Build a Modular Android App Architecture (Google I/O'19)の記事です。
Why Modularize your app?#
People can specialize in certain sections of the application
Maintainability
- grouping layouts based on features
Faster compilation
Faster CI
Only modified module and the modules that depend on that module need to be tested.
How we do it in AndroidX
Discover dependency graph
Find changed fines from Git History
Execute all testes of affected modules
URL: goo.gle/androidx-dependency-tracker
Good for business
- Smaller APKs using the Android App bundle
Isolated feature testing
How to modularize?#
Dynamic Feature Module#
App can’t depend on modules; modules depend on app
onDemand=“false”, onDemand=“true”
Feature Modularization
Layer modularization#
Plaid Features
Persistence
API client / Authentication
Custom Styling Library
Feed UI
Post UI
Isolation via modules#
api vs implementation
if module is provided through api all of the public api are available for all the modules depending on that module.
if module is provided through implementation then all the modules depending on that module cannot see any public api
Feature modularization#
Encapsulation
Possibility for dynamic delivery
Layer modularization#
Isolation to your app
Structure to your app
If you are starting from the monolithic app#
- Start with layer modularization
Working with dynamic feature modules#
Navigation
starting activity
- setClassName
starting fragment
Class.forName()..
Needs ProGuard
No runtime performance hits
=> Currently working on it with navigation jetpack library to make this navigation as natural as possible.
Databases#
One common database
Pros
Very easy to maintain database connection
Easy to share tables
Cons
No isolation between modules
Feature specific entities are in shared domain
One database per module
Pros
- Isolation between modules
Cons
Database connection maintenance
Duplicate data
A hybrid approach
A bright feature with Room#
Multi-module databases with room
Separate databases combined at runtime
Cross-module database queries
Not available yet
Android free modules#
The benefits of it will be..
Faster tests
Minimize dependencies
Separation of concerns
Better abstractions
But do not do this if ..
you don’t have a use case for it / do not use it
you don’t have time; abstraction takes time
TL;DR#
Start re-writing your application in modules
Just options
Always keep your customers and users in your mind
所感・まとめ・個人的に印象に残ったことなど#
モジュール化することでCIでのテスト実行時間も短縮できそう
DFM対応のプロジェクトの画面遷移の実装方法は、今後Navigation Architecture Componentsでより自然な形に改善されそう
Roomには今後マルチモジュールを見据えた機能が追加されそう
アーキテクチャが良いからという理由で☆5つをくれるユーザーはいないよ！何するにしてもユーザーのこと考えてね！が刺さった
以上です！