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.

Eat That Frog- Prepare Thoroughly Before You Begin, Do Your Homework

I have read the book ‘Eat That Frog’, Here is a snippet that I could get from the chapters ‘Prepare Thoroughly Before You Begin’ and 'Do Your Homework':

Prepare Thoroughly Before You Begin

You need to get everything completely ready to work in advance. When everything is laid out in order and sequence you feel much more like getting on with the job.

This seems to be a simple and short thing but it the most important thing before we start anything. It could increase significant changes of successful and perfect completion.  This gives yourself more depth, clear picture to you and prepare your mind for any work.  

Do Your Homework 

If you're not getting better, you're getting worse.

Continuous learning is the minimum requirement for success in any field. 
Read in your field for at least one hour every day. Take every course and seminar available on key skills that can help you.
What are the key skills that can help you the most to achieve better and faster results?

If you wish to purchase a book from AMAZON click here: http://amzn.to/2pnTEQB

Have a great day ahead!