Android-Clean-Architecture-MVVM-Kotlin

Project Overview

This project aims to demonstrate the usage of Android Architecture Components and how this components can be used in an application with a MVVM architecture in Kotlin

Let's explore Architecture Components

According to Android Documentation, Architecture Components are a set of Android libraries for structuring your app in a way that is robust, testable, and maintainable

Why MVVM :

• ViewModel has Built in LifeCycleOwerness.
• ViewModel doesn't have a reference for View.
• ViewModel survive configuration changes (Saving and restoring the UI state).

MVVM Best Pratice:

• Avoid references to Views in ViewModels.
• Instead of pushing data to the UI, let the UI observe changes to it.
• Distribute responsibilities, add a domain layer if needed.
• Add a data repository as the single-point entry to your data.
• Expose information about the state of your data using a wrapper or another LiveData.
• Consider edge cases, leaks and how long-running operations can affect the instances in your architecture.
• Don’t put logic in the ViewModel that is critical to saving clean state or related to data. Any call you make from a ViewModel can be the last one.

LiveData:

• Yes , liveData is easy , powerful , but you should know how to use.
• For livedate which will emit data stream , it has to be in your data layer , and don't inform those observables any thing else like in which thread those will consume , cause it is another
• For livedata which will emit UI binding events, it has to be in your ViewModel Layer.

Coroutines:

It is light wight threads for asynchronous programming, Coroutines not only open the doors to asynchronous programming, but also provide a wealth of other possibilities such as concurrency, actors, etc.

Coroutines benefits:

• Writing an asynchronous code is sequential manner.
• Costing of create coroutines are much cheaper to crate threads.
• Don't be over engineered to use observable pattern, when no need to use it.
• Parent coroutine can automatically manage the life cycle of its child coroutines for you.

Refrences:

• ِAndroid Documentation
• source code for the official Google I/O 2018 for Android app
• Architecture Components Code Lab