Model-View-Presenter (MVP) Architecture

1. Introduction

The Model-View-Presenter (MVP) architecture is a design pattern used for building user interfaces. It separates the application into three components: Model, View, and Presenter. This separation helps in organizing code and improving testability.

2. Key Concepts

Model

The Model represents the data layer of the application, handling business logic and data manipulation.

View

The View is responsible for displaying the data to the user and forwarding user interactions to the Presenter.

Presenter

The Presenter acts as an intermediary between the Model and the View. It retrieves data from the Model, processes it, and updates the View accordingly.

3. MVP Components

Model: Data and business logic
View: UI components and user interactions
Presenter: Handles communication between Model and View

4. Implementation

Here’s a basic implementation of MVP architecture in Java:

interface MainView {
    void showData(String data);
}

class MainPresenter {
    private MainView view;
    private Model model;

    public MainPresenter(MainView view, Model model) {
        this.view = view;
        this.model = model;
    }

    public void loadData() {
        String data = model.getData();
        view.showData(data);
    }
}

class Model {
    public String getData() {
        return "Hello MVP!";
    }
}

class MainActivity implements MainView {
    private MainPresenter presenter;

    public MainActivity() {
        Model model = new Model();
        presenter = new MainPresenter(this, model);
        presenter.loadData();
    }

    @Override
    public void showData(String data) {
        System.out.println(data);
    }
}

public class MVPExample {
    public static void main(String[] args) {
        new MainActivity();
    }
}

5. Best Practices

Avoid direct access to the Model from the View.
Keep the Presenter free of UI logic.
Use interfaces to decouple components.
Make Presenter unit-testable by injecting dependencies.

6. FAQ

What are the advantages of using MVP?

MVP provides a clear separation of concerns, making it easier to maintain and test components independently.

When should I use MVP?

MVP is ideal for applications with complex UIs where separation of logic is crucial for maintainability.

How does MVP differ from MVC?

In MVP, the Presenter is more involved in the UI logic compared to the Controller in MVC, which typically handles user input.