Passing Data between functions in Swift

Question

I'm building a basic App where you have two ViewControllers. On ViewController2 you fill in some text fields, press a button and that data is being sent back to ViewController1 and is displayed inside a tableViewCell.

I went through some Tutorials and managed to accomplish sending the data using a segue and delegation. I ended up with a function which is declared inside a protocol on VC2 and sends the data to VC1. Now I'm wondering how I can use this data inside my tableView function on VC1. I know, this is very basic but I'm a beginner.

Here is my (shortened) Code:

VC2

protocol SendingBookDataProtocol {
func sendDataToHomeController(dataTitle: String, dataAuthor: String, dataCurrentPage: String, dataTotalPages: String)
}

class AddBookController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    
    
    var delegate: SendingBookDataProtocol? = nil

    @IBOutlet weak var textfieldTitle: UITextField!
    @IBOutlet weak var textfieldAuthor: UITextField!
    @IBOutlet weak var fieldCurrentPage: UITextField!
    @IBOutlet weak var fieldTotalPages: UITextField!
    @IBOutlet weak var buttonSave: UIButton!


@IBAction func buttonSave(_ sender: Any) {
        if self.delegate != nil && self.textfieldTitle.text != nil && self.textfieldAuthor.text != nil && self.fieldCurrentPage.text != nil && self.fieldTotalPages.text != nil {
            let titleToBeSent = self.textfieldTitle.text
            let authorToBeSent = self.textfieldAuthor.text
            let currentPageToBeSent = self.fieldCurrentPage.text
            let totalPagesToBeSent = self.fieldTotalPages.text
            self.delegate?.sendDataToHomeController(dataTitle: titleToBeSent!, dataAuthor: authorToBeSent!, dataCurrentPage: currentPageToBeSent!, dataTotalPages: totalPagesToBeSent!)
                  dismiss(animated: true, completion: nil)
              }
}

VC1

class HomeViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, SendingBookDataProtocol {

@IBOutlet var tableView: UITableView!

override func viewDidLoad() {
let nib = UINib(nibName: "BookCell", bundle: nil)
        tableView.register(nib, forCellReuseIdentifier: "BookCell")
        
        tableView.delegate = self
        tableView.dataSource = self
}

    // tableView Functions
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "BookCell", for: indexPath) as! BookCell
        
        cell.title.text = "test"  // this needs to be dataTitle
        
        return cell
    }
    
    func sendDataToHomeController(dataTitle: String, dataAuthor: String, dataCurrentPage: String, dataTotalPages: String) {
        print(dataTitle, dataAuthor, dataCurrentPage, dataTotalPages)
        }
        
        override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
            if segue.identifier == "getBookData" {
                let addBookVC: AddBookController = segue.destination as! AddBookController
                addBookVC.delegate = self
            }
        }

}

Thanks for any help!

Sh_Khan · Answer

1- Create a model

struct Item { 
   let title,author,currentPage,totalPages:String
}

2- Then inside VC1

var item:Item?

func sendDataToHomeController(_ item:Item) {
   self.item = item
   self.tableView.reloadData()
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return item == nil ? 0 : 1
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "BookCell", for: indexPath) as! BookCell
    
    cell.title.text = item!.title
    cell.title.text = item!.author
    //...... and so on

    return cell
}

3- Inside VC2 create item model from the data and use delegate to send it back

@IBAction func buttonSave(_ sender: Any) {

Passing Data between functions in Swift

1 Answers