How can I update the numberOfRowsInSection and how do I show all added values in this tableView?

问题

I am trying to send values from one view controller - NewZoomAddressViewController to another one - Add_EditAddressViewController. I am sending the values to an array in the second view controller (addressArray).

Here is the first view controller:

class NewZoomAddressViewController: UIViewController {

@IBOutlet weak var mapView: MKMapView!
@IBOutlet weak var addressLabel: UILabel!
var addressArray = [String]()

override func viewDidLoad() {
    super.viewDidLoad()
    print("in Zoom map VC")
    mapView.delegate = self
    addressLabel.text = "\(self.sublocalityName!) \(localityName!) \(self.zipName!)"

}
@IBAction func confirmBtn(_ sender: Any) {
    let viewController = storyboard?.instantiateViewController(withIdentifier: "Add_EditAddressViewController") as! Add_EditAddressViewController
    addressArray.append("\(sublocalityName ?? "") \(zipName ?? "") \(localityName ?? "")")
    viewController.addressArray = addressArray
    navigationController?.pushViewController(viewController, animated: true)
}
}

Then here I am adding values to addressArray from NewZoomAddressViewController like below:

class Add_EditAddressViewController: UIViewController,DataEnteredDelegate {
@IBOutlet var addressEDITTableview: UITableView!

  var addressArray = [String]()
override func viewDidLoad() {
    super.viewDidLoad()
    addressEDITTableview.register(UINib(nibName: "EditAddressTableViewCell", bundle: nil), forCellReuseIdentifier: "EditAddressTableViewCell")
    addressEDITTableview.reloadData()

}
}
extension Add_EditAddressViewController : UITableViewDelegate,UITableViewDataSource {

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    return addressArray.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell: EditAddressTableViewCell = tableView.dequeueReusableCell(withIdentifier: "EditAddressTableViewCell") as! EditAddressTableViewCell
    cell.nameHeader.text = "header"
    cell.addressLabel.text = addressArray[indexPath.row]//"\(city) \(pincode) \(locality)"

    return cell
}
}

However, in the table view I am only getting one row. The first time, the single row is okay, but if I add another address - the row is replaced with the new address, and I am no longer getting the old address. How do I show all of the added addresses in the table view?

回答1:

Update: Try out the following code on your Xcode-playground and play around with it to see how it works and try to implement the same logic in your code.

import UIKit
import PlaygroundSupport

class ViewController: UIViewController {
    var array = [String]()
    override func viewDidLoad() {
        super.viewDidLoad()
        let button = UIButton(type: .contactAdd)
        button.center = view.center
        button.addTarget(self, action: #selector(add), for: .touchUpInside)
        view.addSubview(button)
    }
    @objc func add() {
        array.append("New element \(array.count)")
        let controller = TableViewController()
        controller.array = array
        present(controller, animated: true)
    }
}
class TableViewController: UITableViewController {
    var array = [String]()
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        array.count
    }
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = UITableViewCell()
        cell.textLabel?.text = array[indexPath.row]
        return cell
    }
}

PlaygroundPage.current.setLiveView(ViewController())

Store the array outside the function scope and keep adding new elements to the same array instead of a new instance.

In InitialViewController with button action:

var addressArray = [String]()

@IBAction func confirmBtn(_ sender: Any) {
    let viewController = storyboard?.instantiateViewController(withIdentifier: "Add_EditAddressViewController") as! Add_EditAddressViewController
    addressArray.append("\(sublocalityName ?? "") \(zipName ?? "") \(localityName ?? "")")
    viewController.addressArray = addressArray
    navigationController?.pushViewController(viewController, animated: true)
}

In Add_EditAddressViewController:

class Add_EditAddressViewController: UIViewController {
    var addressArray = [String]()
    override func viewDidLoad() {
        super.viewDidLoad()
        addressEDITTableview.reloadData()
    }
}

extension Add_EditAddressViewController: UITableViewDelegate, UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return addressArray.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell: EditAddressTableViewCell = tableView.dequeueReusableCell(withIdentifier: "EditAddressTableViewCell") as! EditAddressTableViewCell
        cell.nameHeader.text = "header"
        cell.addressLabel.text = addressArray[indexPath.row]
        return cell
    }
}

回答2:

addressArray gets deallocated everytime you move back to the screen. You should declare it in Add_EditAddressViewController and append the data there only then send it to otherviewcontroller

  var addressArray : [String] = []

  @IBAction func confirmBtn(_ sender: Any) {

    let viewController = self.storyboard?.instantiateViewController(withIdentifier: "Add_EditAddressViewController") as! Add_EditAddressViewController;
    self.addressArray.append("\(sublocalityName ?? "") \(zipName ?? "") \(localityName ?? "")")
    vc.addressArray = self.addressArray
    self.navigationController?.pushViewController(viewController, animated: true);

}

And then in your otherViewController

var addressArray : [String] = [] { 
      didSet { 
          self.addressEDITTableview.reloadData()
      }
 }
 override func viewDidLoad() {
    super.viewDidLoad()
  }

  extension Add_EditAddressViewController : UITableViewDelegate,UITableViewDataSource {

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    return addressArray.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    let cell: EditAddressTableViewCell = tableView.dequeueReusableCell(withIdentifier: "EditAddressTableViewCell") as! EditAddressTableViewCell
    cell.nameHeader.text = "header"
    cell.addressLabel.text = addressArray[indexPath.row]
  return cell
 }
 }

来源：https://stackoverflow.com/questions/62132321/how-can-i-update-the-numberofrowsinsection-and-how-do-i-show-all-added-values-in