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Android Application Development using Kotlin - 10 || MVP pattern introduction

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Instructor: Abhishek Koirala
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The model-view-presenter software pattern originated in the early 1990s at Taligent, a joint venture of Apple, IBM, and Hewlett-Packard. MVP is the underlying programming model for application development in Taligent's C++-based CommonPoint environment. The pattern was later migrated by Taligent to Java and popularized in a paper by Taligent CTO Mike Potel.
After Taligent's discontinuation in 1998, Andy Bower and Blair McGlashan of Dolphin Smalltalk adapted the MVP pattern to form the basis for their Smalltalk user interface framework. In 2006, Microsoft began incorporating MVP into its documentation and examples for user interface programming in the .NET framework.
The evolution and multiple variants of the MVP pattern, including the relationship of MVP to other design patterns such as MVC, is discussed in detail in an article by Martin Fowler and another by Derek Greer.
MVP is a user interface architectural pattern engineered to facilitate automated unit testing and improve the separation of concerns in presentation logic:
The model is an interface defining the data to be displayed or otherwise acted upon in the user interface.
The view is a passive interface that displays data (the model) and routes user commands (events) to the presenter to act upon that data.
The presenter acts upon the model and the view. It retrieves data from repositories (the model), and formats it for display in the view.
Normally, the view implementation instantiates the concrete presenter object, providing a reference to itself. The following C# code demonstrates a simple view constructor, where ConcreteDomainPresenter implements the IDomainPresenter interface:
The degree of logic permitted in the view varies among different implementations. At one extreme, the view is entirely passive, forwarding all interaction operations to the presenter. In this formulation, when a user triggers an event method of the view, it does nothing but invoke a method of the presenter that has no parameters and no return value. The presenter then retrieves data from the view through methods defined by the view interface. Finally, the presenter operates on the model and updates the view with the results of the operation. Other versions of model-view-presenter allow some latitude with respect to which class handles a particular interaction, event, or command. This is often more suitable for web-based architectures, where the view, which executes on a client's browser, may be the best place to handle a particular interaction or command.
From a layering point of view, the presenter class might be considered as belonging to the application layer in a multilayered architecture system, but it can also be seen as a presenter layer of its own between the application layer and the user interface layer.
Kotlin focuses on multi-platform compatibility and so are the frameworks based on it. The purpose is to focus only once on the business logic and implement it thanks to a framework made to be compatible to each platform. Kodein Framework is a good example of that.
Android development can be a great way to turn your idea into reality or start a promising career as an app developer... and getting started is probably easier than you think.
These days Android Development is done with a tool called Android Studio. Android Studio is kind of like the Microsoft Word of writing Android apps; it helps organize our projects and gives us a user friendly way to create what we’re looking for.