What is mvp pattern

Note: Following steps are performed on Android Studio version 4. Step 2: Modify String. Below is the code for designing a proper activity layout. Skip to content. Change Language. Related Articles. Table of Contents. Save Article. Improve Article. Like Article. OnFinishedListener onFinishedListener ;.

Presenter, Contract. Model : There is some result available, Controller. I have created a field variable in my instance and filled it with the result. Presenter : Thanks for waiting View , I found a list of matching results for you and arranged them in a presentable format: ["Piano Teacher ","Piano "]. Please show it to the user in a vertical list. Also please hide the progress bar now [ MVP ]. Controller : Thanks for waiting View , I have asked Model about your search query.

It says it has found a list of matching results and stored them in a variable named "searchResultsList" inside its instance. You can get it from there. Also please hide the progress bar now [ MVC ]. Should the production year of the movie come first or last? Should it be in a vertical or horizontal list?

Even though the sample is written for android, the underlying principles can be applied to any medium. MVC is a pattern for the architecture of a software application. It separate the application logic into three separate parts, promoting modularity and ease of collaboration and reuse. It also makes applications more flexible and welcoming to iterations. It separates an application into the following components:.

To make this a little more clear, let's imagine a simple shopping list app. All we want is a list of the name, quantity and price of each item we need to buy this week. Below we'll describe how we could implement some of this functionality using MVC. If you want to see a sample with simple implementation please check this GitHub post. A concrete workflow of querying and displaying a list of users from a database could work like this:. View is more loosely coupled to the model.

The presenter is responsible for binding the model to the view. Also worth remembering is that there are different types of MVPs as well. Fowler has broken the pattern into two - Passive View and Supervising Controller.

When using Passive View, your View typically implement a fine-grained interface with properties mapping more or less directly to the underlaying UI widget. Your Presenter class will talk to the model and "map" it to the view. This approach is called the "Passive View". The disadvantage is that you can't leverage things like databinding which is really powerful in frameworks like WPF and Silverlight. In that case your View might have a property called Customer, which then again is databound to the UI widgets.

You don't have to think about synchronizing and micro-manage the view, and the Supervising Controller can step in and help when needed, for instance with compled interaction logic. He covered all the flavors of MVP and showed C code to implement them. In some cases the model can also be used to turn a data source into a higher level abstraction as well.

A good example of this is the MVC Storefront project. The distinction made is that in an MVC application traditionally has the view and the controller interact with the model, but not with each other.

Having said that, ASP. To perhaps get an idea of the ASP. Both are patterns trying to separate presentation and business logic, decoupling business logic from UI aspects.

That means that in MVP standard web form page life cycle is just enhanced by extracting the business logic from code behind. In other words, page is the one servicing http request. MVC on other hand changes completely the game because the request gets intercepted by controller class before page is loaded, the business logic is executed there and then at the end result of controller processing the data just dumped to the page "view" In that sense, MVC looks at least to me a lot to Supervising Controller flavor of MVP enhanced with routing engine.

If one would consider himself good in web forms, I would suggest MVP. If one would feel not so comfortable in things such as page life cycle etc MVC could be a way to go here. I would say that MVP in this scenario is a quick win. In MVP you can have a single view working with multiple types of presenters and a single presenter working with different multiple views.

So, if for example, the model is a car, then the presenter is some sort of a car presenter, exposes the car properties year, maker, seats, etc. The view knows that the text field called 'car maker' needs to display the presenter Maker property. You can then bind to the view many different types of presenter, all must have Maker property - it can be of a plane, train or what ever , the view doesn't care. The view draws data from the presenter - no matter which - as long as it implements an agreed interface.

MVC is great, but the problem is that usually its controller per view. Controller A knows how to set fields of View A. At this level of granularity, MVP makes little sense. When one on the contrary go to larger scales, proper interface becomes more important, the same with unambiguous assignment of responsibilities, and here comes MVP.

On the other hand, this scale rule of a thumb, may weight very little when the platform characteristics favours some kind of relations between the components, like with the web, where it seems to be easier to implement MVC, more than MVP. The article also matches what Uncle Bob Martin said in his one of his talks: that MVC was originally designed for the small UI components, not for the architecture of the system.

In brief, it is. The simplest answer is how the view interacts with the model. In MVP the view is updated by the presenter, which acts as as intermediary between the view and the model.

The presenter takes the input from the view, which retrieves the data from the model and then performs any business logic required and then updates the view. In MVC the model updates the view directly rather than going back through the controller. IMO, MVP is an improved version of MVC where you basically separate the concern of what you're gonna show the data from how you're gonna show the view. The presenter includes kinda the business logic of your UI, implicitly imposes what data should be presented and gives you a list of dumb view models.

And when the time comes to show the data, you simply plug your view probably includes the same id's into your adapter and set the relevant view fields using those view models with a minimum amount of code being introduced just using setters. In MVC, we talk through interfaces boundaries to glue different layers.

A controller is a plug-in to our architecture but it has no such a restriction to impose what to show. An action is performed on the Controller , which will execute an action on the Model. That action in the Model , will trigger a reaction in the View. The View , is always updated when the Model 's state changes. MVC wasn't originally created for the Web, but for Desktop applications instead, where the Controller, Model and View would co-exist together.

Because we use web frameworks eg:. Laravel that still use the same naming conventions model-view-controller , we tend to think that it must be MVC, but it's actually something else. Instead, have a look at Action-Domain-Responder. So far, the same. When a new action is requested on the same component, the Controller is called again, and the cycle repeats itself.

Note: Wikipedia states that " Each ADR action, however, is represented by separate classes or closures. This is not necessarily true. Several Actions can be in the same Controller, and the pattern is still the same.

In MVC, the Controller is the one in charge! It communicates with the Model to get the appropriate data. Then, it shows a new View that resembles the profile page. The Controller may take the data from the Model and feed it directly to the View -as proposed in the above diagram- or let the View fetch the data from the Model itself.

In MVP, the View is the one in charge! The Presenter will do the required logic and any needed communication with the Model then, calls back the View through its interface so that the View can display that the save has been completed. This came to a picture in early where Microsoft introduced Smart Client windows applications.

A presenter is acting as a supervisory role in MVP which binding View events and business logic from models. The view is the initiator for user inputs and then delegates the events to the Presenter and the presenter handles event bindings and gets data from models. Pros: The view is having only UI not any logics High level of testability. Controller is responsible for creating models and rendering views with binding models. Two of the most common ones are repository and unit of work. For example, consider how much UI and data access technologies have changed over the years and the number of choices we have available today.

Actually, there are not a whole lot of differences between them. Both patterns focus on separating responsibility across multi components and promote loosely coupling the UI View from the business layer Model.

The major differences are how the pattern is implemented and in some advanced scenarios, you need both presenters and controllers. Here are the key differences between the patterns:. Or MVC for short is a widely used design pattern for architecting software apps. The pattern was originally designed by Trygve Reenskaug during his time working on Smalltalk where it was initially called Model-View-Controller-Editor. The pattern breaks an app up into three components.

This pattern based on MVC and MVP which attempts to more clearly separate the development of UI from that of the business logic and behavior in an application. It has three main components as follows. Performance Evaluation — When we are testing the UI performance, MVP turns out to be the one with the highest reliability and lowest hindrance when it comes to rendering frames. Data binding in MVVM creates an additional overload that could drastically affect its performance when performing complex tasks.

Compatibility — When testing the patterns based on their compatibility, MVVM was the best of the lot due to its data binding which had a positive impact.