VIPER- Class binding using Protocol

In last post we have seen how to bind all classes together. In this post we would see app flows from view controller to interactor and to view controller.To make it more decoupled we would generate some protocols and implement it in classes.

Step:1 list-ViewController

override func viewDidLoad() {
        super.viewDidLoad()
        DispatchQueue.global().async {
            self.eventHandler?.updateView()
        }
    }

Step:2 list-Presenter

func updateView() {
        listInteractor?.findListData()
    }

Step:3 list-Interactor

func findListData() {
        //Find data
        //output?.foundListData(aList: nil);
        let reader = FileReader()
        if let data = reader.readJsonFile(name: "company") {
            let myArr:NSArray? = ParseData(aObject: data)
            if myArr != nil {
                output?.foundList(aList: myArr);
            }
        }
    }

Step:4 list-Presenter

func foundList(aList:NSArray?) {
        let sortedArray:NSArray? = self.SortCompanyList(aList: aList)
        if(sortedArray != nil) {
            userInterface?.reloadList(alist: sortedArray)
        }
        else {
            userInterface?.showNoContenctView()
        }
    }

Protocols:
1) ViewController Interface:
Implemented   by ViewController
Object owned by Presenter

protocol listViewInterface {
    func showNoContenctView()
    func reloadList(alist:NSArray?)
}
*********************************************************
class ViewController: UIViewController,listViewInterface
 {
  //MARK: listViewInterface methods implementation
    func reloadList(alist:NSArray?) {
        //reload table view
    }
    func showNoContenctView() {
     //Show alert code
    }
 }
*********************************************************
class listPresenter: NSObject {
    var userInterface:listViewInterface?
}

2) Presenter Interface:
Implemented by Presenter
Object owned by ViewController

protocol listPresenterInterface {
    func updateView();
}
*********************************************************
class listPresenter: NSObject,listPresenterInterface {
    var userInterface:listViewInterface?
    func updateView() {
        //Call for data adjustment and interactor calling
    }
}
*********************************************************
class ViewController: UIViewController,listViewInterface {
   var eventHandler:listPresenterInterface?
   override func viewDidLoad() {
     super.viewDidLoad()
     self.eventHandler?.updateView();
   }

   //MARK: listViewInterface implementation
    func reloadList(alist:NSArray?) {
        //reload table view
    }
    func showNoContenctView(){
        //Show alert code
        }
 }

3) Interactor Input Interface:
Implemented   by interactor
Object owned  by presenter

protocol listInteractorInput {
    func findListData()
}
*********************************************************
class listInteractor: NSObject,listInteractorInput {
    func findListData() {
        //Find data
    }
*********************************************************
class listPresenter: NSObject,listPresenterInterface {
    var listInteractor:listInteractorInput?
    func updateView() {
     //Code for data adjustment and interactor calling
     listInteractor?.findListData();
    }
}

4) Interactor output Interface:
Implemented   by presenter
Object owned  by interactor

protocol listInteractorOutput {
    func foundList(aList:NSArray?)
}
*********************************************************
class listPresenter: NSObject,listPresenterInterface,listInteractorOutput {
    var listInteractor:listInteractorInput?
    var userInterface:listViewInterface?
    
    func updateView() {
        listInteractor?.findListData();
    }
    func foundList(aList:NSArray?) {
       userInterface?.reloadList(alist: sortedArray);
    }
}
*********************************************************
class listInteractor: NSObject,listInteractorInput {
    var output:listInteractorOutput?
    func findListData() {
        //Find data
    }
}

Note:Presenter is implementing two protocols.
This is the end of the post. In next post we will see how VIPER is useful for testing and coverage.