Writing a modular Android Application

Talk given at the Mumbai Android Developers Meetup on the 24th of February 2018.

Covers the need and process for modularizing an Android app.

Article here: https://medium.com/mindorks/writing-a-modular-project-on-android-304f3b09cb37

Project here: https://github.com/karntrehan/Posts/

Transcript

1. Writing a modular
   Android Application
   - Karan Trehan
   Android @ m.Paani
   @karntrehan
   

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2. What?
   What is a modular Android Application?
   How?
   How do I go about making my app modular?
   Why?
   Why do I or my users need it?
   2
   

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3. “
   3
   What?
   Modular programming is a
   software design technique that
   emphasizes separating the
   functionality of a program into
   independent, interchangeable
   modules, such that each contains
   everything necessary to execute
   only one aspect of the desired
   functionality.
   -https://en.wikipedia.org/wiki/Modular_programming
   

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4. 4
   Default structure
   Drawbacks:
   ▪ No shared utils
   ▪ Cumbersome code navigation
   ▪ No Instant Apps
   ▪ Slow gradle builds
   

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5. 5
   Modular structure
   Advantages:
   ▪ Faster gradle builds
   ▪ Re-usability of common functionality
   ▪ Easily “Instant” your apps
   ▪ Better teamwork (Ownership)
   ▪ Smoother Git Flows
   

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6. Initial doubts with a modular
   Android App
   ▪ What architecture do I use?
   ▪ Is my choice of language going to impact me?
   ▪ How do I define my modules?
   ▪ What is a core module?
   ▪ How do I use 3rd party libraries?
   ▫ Room?
   ▫ Dagger 2?
   6
   

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7. Architecture
   Which one do I choose?
   MVP
   Presenter
   communicates between
   the view and the model
   7
   MVVM
   Viewmodel
   communicates between
   the view and the model
   Clean
   Like MVP, the model
   contains use cases
   which can be shared
   across multiple models
   MVI
   For each user action an
   intent is dispatched by
   the View and observed
   by the Presenter
   Reductor
   Redux inspired to make
   state mutations easier
   to read, write and
   reason about
   Custom
   Your custom
   implementation
   

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8. CHOOSE ANY!
   Your architecture choices in no way impact the
   modular-ness of your app!
   Better, you can have different architectures in different
   modules.
   8
   

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9. 9
   Language
   Which one do I write my modules in?
   VS
   

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10. But, please, give Kotlin a try!
    Again,
    CHOOSE ANY!
    10
    

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11. 11
    Modules
    What goes in which module?
    ▪ Identify app flows
    ▪ Create feature modules
    ▪ Non-UI modules
    ▪ Examples:
    ▫ authentication
    ▫ onboarding
    ▫ settings
    ▫ account
    ▫ notification
    

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12. 12
    Core Module
    Why do I need one?
    ▪ Utility classes and extension functions
    ▪ Global classes and callbacks
    ▪ Initiate libraries
    ▪ Provides global dependencies to
    dependency injection framework
    

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13. 13
    core
    stores
    rewards home notification
    authentication
    dependent’s build.gradle
    Module dependency structure
    

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14. 14
    3rd Party Libraries
    Where do I add them and initialize them?
    core’s build.gradle core’s CoreApp.kt
    

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15. 15
    Room
    How do I use this awesome library?
    ▪ New db into each feature
    module
    ▪ Migrations are modularized
    ▪ Instant apps contain only
    those tables they need
    ▪ Queries will be faster
    

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16. 16
    Dagger 2
    How do I handle my dependencies?
    

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17. Actual Code
    Implementation!
    ▪ Modular
    ▪ Kotlin
    ▪ Rx
    ▪ Retrofit
    ▪ LiveData
    ▪ ViewModel
    ▪ Tests
    https://github.com/karntrehan/posts
    Place your screenshot here
    17 @karntrehan
    

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18. THANK YOU!
    Have fun modularizing
    your apps!
    @karntrehan Template from: Mowbray, Link: https://goo.gl/XVJRqH
    

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