This document discusses using a modular architecture approach for Android projects. It proposes decomposing large apps into independent modules based on features or functions. This allows each module to be developed separately by different teams. The document provides examples of common module types like authentication and checkout. It describes advantages like reusability and easier collaboration. Communicating between modules can be done through interfaces or an event bus. The modular approach is compared to a traditional monolithic architecture.

1. Modular Android Project
Raka Westu Mogandhi
Mobile Engineer @prismapp.io

2. Table of Contents
- Background
- Solution
- Case Study
- Conclusion

3. Background

4. Single Application Module

5. - Architecture → Model-View-Presenter
- HTTP data source → Retrofit
- Local data source → SQLite
- Packaging strategy → feature based
Common Implementation Stack

6. - Highly coupled code
- Hard to add new feature or just update the feature
- Single implementation style
- New members will need time to adapt the new style
- Adapting new technology may need to refactor entire app
- Not good enough for team workflow
- Working one one module may cause conflicts when integrating new feature
Common Weaknesses

7. Solution → App Decomposition

8. Approach Microservice is a particular way of
designing software applications as
suites of independently deployable
services.Microservice like Architecture
using Android Module

9. What is Android Module?
- It is a component of Android project.
- Module types
- Library
- Application
- An Android project can consists of several modules
- Each module can be developed independently

10. Examples of Android Module
- Android support libraries
- Firebase android libraries
- Third party libraries
- Glide
- RxJava
- Retrofit

11. Applying App Decomposition

12. How can we do it?
- Decompose app into several independent components
- The approach is based on our team and project needs
- Base → feature, function
- Approach example
- Ecommerce app can be decomposed based on feature
- Login module
- Products module

13. Case Study
Ecommerce App
Analytics
Module
Ecommerce
App
Checkout
Module
Products
Module
Authentication
Module
History
Module

14. App Flow
Show login page if user is isn’t
authenticated
Show product catalog if user is already
authenticated
Start
Show login page
Auth.
startLoginPage
Auth.
isLoggedIn
Show product catalog
Prod.
startProductCatalogPage
yes
no

15. App Flow (Contd)
Show product catalog
Show product search
Show product details
- Add to favorites
- Add to cart
Product Catalog Product Details
Add to cart
Checkout
.AddProductToCart
Add to favorites
Product Search
Show shopping cart
Checkout
.startShoppingCartPage

16. App Flow (Contd)
Add to cart from product page
Remove item from shopping cart page
Go to payment
Show transaction history
Add to cart
Redirect to
shopping cart
page
Continue shopping
Back to previous
screen
Shopping Cart Page
Remove item
from cart
Go to payment Finish payment
Show transaction history
History.
showTransactionHistory

17. Authentication
Module
- Login
- Register
- Forgot password
Example Auth module abstraction
// Start page
ModularAuth.getInstance().startLoginPage()
// Check if already logged in
val loggedIn =
ModularAuth.getInstance().isLoggedIn()
// Get Authenticated user data
val userData =
ModularAuth.getInstance().getAuthenticatedUse
r()

18. Products Module
- Products catalog → product
details
- Products search → product
details
- Products favorites
- Get product in favorites
Example Products module abstraction
// Start page
ModularProd.getInstance().startProductCatalog
Page()
ModularProd.getInstance().startProductSearchP
age()
ModularProd.getInstance().startProductFavorit
esPage()
// Get Data
val favorites =
ModularProd.getInstance().getFavoriteProducts
()

19. Checkout Module
- Add product to cart
- Start checkout screen
- Start payment preview
- Get current active checkout
data
- Get current cart data
Example Checkout module abstraction
// Start page
ModularCheckout.getInstance().addProductToCar
t()
ModularCheckout.getInstance().showCheckoutPag
e()
// Get Data
val carts =
ModularCheckout.getInstance().getShoppingCart
()

20. History Module
- Show all generated transaction
Example History module abstraction
// Start page
ModularHistory.getInstance().startAllTransact
ionsPage()
// Get Data
val transaction =
ModularHistory.getInstance().getTransactionDe
tails()

21. Analytics Module
- Track event
Example Analytics module abstraction
// Track Event
ModularAnalytics.getInstance().trackEvent()

22. App Module
- Starting point of the application
- Compose the available modules in here
- App module have dependencies to each modules

23. How to communicate between modules?
- Using interface or callback
- Event bus

24. Interface or Callback Example
EcommerceAuth.getInstance.startLoginPage(object: LoginResultListener {
override fun onLoginSuccess() {
}
override fun onLoginFailure() {
}
})

25. Example Code
github.com/rakawestu/modular-android-example

26. Advantages
- Good for teams
- Each person/small team can work on small independent module
- Each module can have different implementation style
- Some module can be reused on different app
- Common implementation module → base activity, base fragment, etc.
- Utils module → string utilities, money utilities, etc.
- The module is generic

27. Disadvantages
- Documentation should be clearer because communication between
module is important
- There may be a duplicate code because implementation between module
are similiar → can be minimized if using common module for repeated
codes
- More build time on complete app

28. - https://nearsoft.com/blog/the-microservices-approach-and-how-it-beats-
monolithics/
- https://medium.com/@tomsoderlund/micro-frontends-a-microservice-
approach-to-front-end-web-development-f325ebdadc16
Slide: bit.ly/modAndroid2017
References

29. Thank you!