mohammedysamir / architecture_practice

Android architecture patterns practice {MCV,MVP,MVVM}

Architecture_Practice

Android architecture patterns practice {MCV,MVP,MVVM} This Repository is initiated to practice 3 android architectures, explanation is provided by Ahmed Azz channel.

MVC:

• Stands for Model-View-Controller.
• Traditional architecture for mobile and web applications.
• Define Model for data storage (data class, APIs, DB).
• Depends on composition between the Controller and the View -> controller has reference of its view.
• Android project affect this architecture to define both the controller and the view dependently (drawback).
• Suits small applications.

Diagram

MVP:

• Stands for Model-View-Presenter.
• Try to separate computations from the View.
• Computations are delegated to the Presenter.
• Suits middle-size projects.
• We need to define an interface for each View and then implement it.
  • This is the Preseneter responsibilities.
  • Presenter will get View's inputs using those functions declared in the interface.
  • Send data to model
  • Get updated data from model.
  • Send them back to the View (also we could do computations in presenter)
• How the presenter will send data back to the view?
  • We need to define an interface for each view that will define functions with parameter of type model.
  • Those funcitons will be implemented in the View class -> get model object and update View's UI.

Diagram

MVVM

• Most recent and most used architecture in large-size applications.
• Based on Observer pattern.
• Views are separated from the ViewModel.
• ViewModel can't communicate directly with the Models.
• Repositories will deal with Models (remote, local), update or fetch data to ViewModels.
• Logic can be delegated to either ViewModel or the Repository.

  • For DIP and Strategy pattern: We declare repository interface then implement it, ViewModel will have a reference to repository interface to update or fetch data.

  • View must have a reference to ViewModel -> can be done through composition or XML tag.

  • ViewModel will get View's inputs then handle them to repository object defined in it.

  • Repository object will update model and fetch new updated data using MutableLiveData and return it to the VM.

  • VM will get repo's MutableLiveData, do computations and return final data to View as LiveData.

  • The View will observe ViewModel's data using:

    vmObj.observe(this,Observe{ liveDataObj->
      //update UI using liveDataObj's data
    })
    

Diagrams:

Hope my explanation was easy to understand 😊✌