Introduction
In this blog, we will study the design pattern known as MVC (Model View Controller) and why iOS app developers should apply the MVC pattern in their iOS applications.
What is the Model View Controller in iOS?
The core principal behind MVC is that the visual content in your app, is stored at a separate place from your data. So, the change in the user interface does not break your code. Here are the features of MVC in iOS.
- Design pattern, or the way of organizing the code.
- Not unique to Cocoa or Swift.
- Keeps visual content separate from the data
How MVC works
- In Model, we see our data, like an email sending app or text messaging in context of the application
- The View is a user interface of our app.
How we make connections
- The whole Xcode Window is considered as a View in which you have multiple sub Views.
- Views are held in xib file.
- Code is written in one or more Swift files.
Your goal is to connect to the information which is entered in the text field, shown in the above image.
The text field in the image is our controller. We want the information to be passed when the user clicks the button. For this, we make a connection by defining a text field as an outlet. Then we access our data through View Controller. If we want to perform any action, we define the action in Swift.
Now, let's move forward and see the separate concept of MVC.
Model
- Representation of what your app does (using custom classes, subclasses from NSObject, for example).
- Tutorial App will have tutorial classes, Note App will have note classes, and Painting App could define a painting class.
- Other responsibilities if using core data (NSManagedObject) or Realm database (RLMObject)
View
- View and Controls, and layer objects provide the visual representation of your App.
- View: Objects that draw content in a designated rectangular area and respond to the events in that area.
- Control: “Special” View that implements a commonly used interface, like buttons, text fields, toggle, switches etc.
Controller
- Manages the presentation on screen.
- A View Controller manages a single View and its collection of sub-Views.
- When presented, the View Controller makes its Views visible by installing them in Apps window.
- Uses base class for UIViewController; means that when you create the project, it asks which type of class you want to inherit in your project. So, you select the class and at this point, UIViewController is our sub class.
Conclusion
MVC is a design pattern for all programming languages. In iOS, developers must follow the MVC pattern because it helps the developers in making separate portions which do not affect each other without the developer's permission. Following the MVC pattern makes your code understandable and easily readable for new developers. In this modern era, the MVC Object Oriented principles are the key to success. So, new developers should focus on this concept because this concept is being applied in all programming languages nowadays. Thus, you should study the MVC concept and try to build an App with MVC pattern.