[Swift5] How to communicate from ViewController to Model and pass a value

ViewController role

VIewController is a class that manages and operates (displays, hides, arranges, animates, etc.) the View that is displayed as its name suggests.

After that, it has the role of displaying and managing Text and View according to the received data.

Role of Model

It is in charge of business logic in the system, and it is the role of Model to actually process the data. For example, it is the model that processes the api.

About MVC model

It is one of the architectures in application development.

Besides MVC models, there are MVP, MVVM, etc. Details about the MVC model can be found at the URL below. https://qiita.com/s_emoto/items/975cc38a3e0de462966a

Model preparation

First, create a class on the Model side and prepare properties and init (initializer (initial value)).

`SampleModel.swift`


class SampleModel {

    //Property to put the value passed from Controller
    var sampleValueA: String?
    var sampleValueB: String?
    var sampleValueC: String?

    //Receive value from Controller (initializer (initial value))
    init(firstSampleValue: String, secondSampleValue: String, thirdSampleValue: String) {

        sampleValueA = firstSampleValue
        sampleValueB = secondSampleValue
        sampleValueC = thirdSampleValue
    }

Description on the Controller side

Write the code first.

`ViewController.swift`


class SampleViewController: UIViewController {
    
    //Value to pass to SampleModel
    firstSampleValue  = "firstSampleValue"
    secondSampleValue = "secondSampleValue"
    thirdSampleValue  = "thirdSampleValue"

    override func viewDidLoad() {
        super.viewDidLoad()

        startSampleModel()
    }
    
    //Method to communicate with SampleModel
    func startSampleModel() {

      let sampleModel = SampleModel(firstSampleValue: firstSampleValue, secondSampleValue: secondSampleValue, thirdSampleValue: thirdSampleValue)
    }
}

Call the init created by Model on the Controller side and put the property created by Controller into the Model init.

Then, the process is performed in the init of Model, and in this case, the character string" firstSampleValue " created by Controller becomes sampleValueA, and thecharacter string "secondSampleValue"is the character string. In sampleValueB, the string" thirdSampleValue " is in sampleValueC.

Now you can pass values from Controller to Model.

Finally

In the next post, I will post about ** How to return a value from Model to Controller **. This is the sequel to this article.

Please refer to it!