Developing an Ios application combines of a lot of processes and each one of them hold their own specific value. Among these, particular one is architectural patterns of design whose most important function is aiding in de-cluttering and organising of code. And since this is an essential step in developing an app, you should be aware of all the options that you have in hand regardless of the fact weather you are developing an ios app by yourself or hiring an ios App Development Company to do the job for you. 

Not a long time back, people have not even heard of the patterns that I mentioned in the title, in fact in order to create an app, developers have to put all their money on total three options namely, the decorator pattern, the singleton pattern and the bridge design pattern. These pattern had their fair share of success but they started to phase out of people’s memory as soon as they started throwing up issues of interactions among clients and servers. Soon, ios started to shift towards the newer and more capable patterns that were presented in the market in the form of MVP, MVVM, MVC and Viper. 

Though a headache came along with it for the app developers and that was to decide which one suits best with their vision of app creation. So, let us run right through all the design architectures and decide which one suits the best for you. 

The MVC Pattern 

MVC actually stands for Module View Controller and it was introduced to the world by Trygve Reenskaug who was a Norwegian computer engineer. It can easily be regarded as a parent to all the other pattern sin the list as this was developed as early as 1970. To make it more fascinating for you, I would like to add that it was the first human shot at object-oriented programming. 

Since we have discussed that MVP pattern consists of three parts, let us have a closer look all the three parts. View displays everything for the user of the system. Model handles the business entities, databases and the rest of the data. Controller is provided with the responsibility to handle the work of the model, provide data to database and bring the data from the view to the database and vice versa. 

However, one problem arises in this pattern. Apple has a very tight link between Controller and View which makes them almost one entity while the Model stays separate. The problem arises in the testing process as only the Model can be tested in this case because the closely knit link between the Controller and View prevents them from being tested. 

The strong connection between the Controller and View is not healthy for the software and because of this MVP scores a little over MVC. 

The MVP Pattern 

MVP is regarded as Model View Presenter. It has two specific points which makes it vastly different from MVC. Now, let us have a look at the parts that it consists of:

The Model 
  • View and Model are loosely linked. The Presenter has to bind the View to the Model.
  • All the interactions with view takes place via a proper interface which in turn makes it a lot easier to test the unit.
  • In general, Presenter to View happens on a one to one basis, although complicated views might attach themselves with multiple presenters. 
The MVC Pattern 
  • Controllers depend on behaviours. It can easily get shared across the view.
  • It handles the responsibility of determining the right view of displaying. 

The overall function of model stays the same in this case. Business logic is taken care of by the presenter. But the most interesting part of this pattern is the view which mainly has two components, the View Controller and View, both of them handles interaction. 

In the debate of MVVM vs MVC, former has the responsibility of solving the issues of heavy connection between the controller and View modes that are present in the MVC patterns. On top of all this, the problem of testing also gets solved as the Presenter, user interaction, View, Model all can be tested. 

The highest level of inconvenience lies in the Presenter because it is too big in size and it still take note of all the present business logics.

The MVVM Pattern

MVVM is known as ‘Model View-View Model’ and was created in the year of 2005 by an architect from Microsoft whose name was John Gossman. There are three main parts of this model.

Model is related to implementing the domain model of the application in order to involve all the key components such as data model, business logic and validation. Examples of various model projects are DTOs (data transfer objects), POCOs (Plain Old CLR Objects), generated entity, proxy objects and repositories. 

View, as it can be judged by its name is all that the user can see, for example the layout, the structure and how everything else shows up on the screen. View is the app page that shows up within the application. View’s main job is to receive, store and send out updates only to the View-Model. The only thing view is not responsible for is the communications that occurs between the Model and this part. 

How MVVM and MVC differs in ios?

First basic difference is that of distribution pattern which is much better in MVVM in comparison to MVC but there is a hiccup in this in form of it this being immensely overloaded. Testing plays a vital role in this area and just by writing the right code no one can guarantee the fact that project is going to work as everyone expected is to. This is the prime reason why testing is paramount to check its effectiveness. 

The Viper Pattern 

The ios app developers got hold of this clean piece of architecture on the Clean Coders when the search for the right architectural solution was still in the running. Now, if you are wondering what exactly is Clean Coders then you to be aware that it is a renowned platform that arranges generally set up in order to aim at the software professionals of the world. 

This new architecture was designed to split the logical structure of the application into a number of responsibility levels. This splitting pattern was pretty helpful in increasing the testing capacity of the different levels and solving the tight connection problems. 

Viper pattern for ios app design

Viper is the best example of cleaner architecture in the quest of building the ios applications. Viper also has an acronym in the name of ‘View-Interaction-Presenter-Entity-Routing’.

Now, let us have a close look at all the parts that it consists of:

  • View has exactly the same actions which the user has for an interface.
  • Entities in actual are in correspondence with the Interactor. Presenter has been assigned with the task of informing the Interactor regarding the developments in View. Entity is other aspect that Viper is associated with and the task of Interactor is to send the data that it receives from Entity to the Presenter. Next step consists of View mirroring it to the user. All the associated sites, data models and entities are linked to the Interactor.
  • Presenter is the one with the least responsibilities. It just receives the updates from the entity while sending the data to it.
  • Entity has the control of the objects that the Interactor looks after like the content and the titles. Without the intervention of the Interactor, it is impossible for Entity to get in touch with the Presenter.
  • Routing is also known as the wideframe and the reason behind this is that it helps in navigating between the screens. The task that Routing is assigned with is handling the objects of UINavigationController, UIWindow and the likes. UIkit is the ultimate framework on which it is developed in an ios app design architectural pattern. UIkit is equipped with all the basic components of MVC and on top of that is also does not contain the tight link that makes lives difficult for the codes. 

All in all, Viper is great if we consider unit testing because the amazing distribution that it provides allows you to run tests on various available functions. This feature alone solves the major issue that cause headache to developers when they use MVVM, MVP and MVC software pattern. However, Viper is not perfect has couple of aspects that are difficult to get hold of. 

Conclusion:

So, after going through all software patterns thoroughly, we can conclude that none of them can be crowned as number one as all of them have their plus and minus points. So, if want to succeed like no other you have to take the gamble of mixing two or three patterns and see how it pans out. 

Arun Goyal

Managing Director @ Octal IT Solution, a prominent Mobile App Development Company offering cutting-edge iPhone App Development and Android App Development services to Startups, SMEs and Fortune-500 Companies.

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