I am a beginner to iOS coming from the android background and just learned about table view (for me it's an Android ListView). I am trying to separate data source & delegate from view controller. I found some tutorials on how to do so but stuck at figuring out how to send the clicked item to another view controller. The code is below:
class PictureTableViewController: UIViewController {
@IBOutlet weak var pictureTableView: UITableView!
private let picsDataSource: PicturesDataSource
required init?(coder aDecoder: NSCoder) {
self.picsDataSource = PicturesDataSource()
super.init(coder: aDecoder)
}
override func viewDidLoad() {
super.viewDidLoad()
pictureTableView.dataSource = picsDataSource
pictureTableView.reloadData()
pictureTableView.delegate = picsDataSource
}
}
class PicturesDataSource: NSObject, UITableViewDataSource, UITableViewDelegate{
private var pictureModels = [PictureModel]()
override init(){
let picModelsDataController = PictureModelsDataController()
pictureModels = picModelsDataController.pictureModels
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return pictureModels.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: PictureCell.self)) as! PictureCell
let picModel = pictureModels[indexPath.row]
cell.pictureName = picModel.pictureName
cell.imageItem = picModel.imageItem
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
//1 - try loading the "Detail" view controller and typecasting it to be DetailViewController
if let detailViewController = storyboard.instantiateViewController(withIdentifier: "PictureDetailView") as? PictureDetailViewController {
//2 - success! set its selecteImage property
detailViewController.selectedImgName = pictureModels[indexPath.row].pictureName
//3 - now push it onto the navigation controller
navigationController?.pushViewController(detailViewController, animated: true)
}
}
}
Error in: func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath){ }
. since "storyboard" & "navigationController" are not available in PicturesDataSource class, how can I send clicked item(picture name) to the DetailsViewController
There are StackOverflow answers about separating data source and delegate but did not solve my problem.
Using: Xcode 8.3 beta 6
You can include a reference to main view controller at your table view events handler. Below is a playground code I derived from your example:
import UIKit
// MARK: - Model
struct Picture {
let title: String
let image: UIImage
}
struct PictureModelsDataSource {
let pictures = [
Picture(title: "exampleTitle", image: UIImage(named: "exampleImage")!),
Picture(title: "exampleTitle", image: UIImage(named: "exampleImage")!)
]
}
// MARK - View
class PictureCell: UITableViewCell {
@IBOutlet weak var pictureTitleLabel: UILabel!
@IBOutlet weak var pictureImage: UIImageView!
}
// MARK: - Controller
class PictureTableViewController: UIViewController {
// MARK: - Properties
@IBOutlet weak var pictureTableView: UITableView!
private var pictureListController: PictureListController?
// MARK: - View lifecycle
override func viewDidLoad() {
super.viewDidLoad()
pictureListController = PictureListController()
pictureListController?.viewController = self
pictureTableView.dataSource = pictureListController
pictureTableView.delegate = pictureListController
pictureTableView.reloadData()
}
}
class PictureDetailViewController: UIViewController {
var selectedPictureTitle: String?
}
class PictureListController: NSObject, UITableViewDataSource, UITableViewDelegate {
// MARK: - Properties
weak var viewController: PictureTableViewController?
private let pictures: [Picture] = {
let pictureModelsDataSource = PictureModelsDataSource()
return pictureModelsDataSource.pictures
}()
// MARK: - View setup
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
// MARK: - Event handling
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return pictures.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = tableView.dequeueReusableCell(withIdentifier: String(describing: PictureCell.self)) as? PictureCell else {
return UITableViewCell()
}
let picture = pictures[indexPath.row]
cell.pictureTitleLabel.text = picture.title
cell.pictureImage.image = picture.image
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let pictureTitle = pictures[indexPath.row].title
let storyboard = UIStoryboard(name: "exampleStoryboard", bundle: nil)
if let pictureDetailViewController = storyboard.instantiateViewController(withIdentifier: "PictureDetailView") as? PictureDetailViewController {
pictureDetailViewController.selectedPictureTitle = pictureTitle
viewController?.navigationController?.pushViewController(pictureDetailViewController, animated: true)
}
}
}
See StoryBoard
object can be obtained by using this
let storyboard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
Now your second question is about how to get navigation controller. It means how to get currentViewController
in your case. This can be get by below code
func getCurrentViewController() -> UIViewController? {
if let rootController = UIApplication.shared.keyWindow?.rootViewController {
var currentController: UIViewController! = rootController
while( currentController.presentedViewController != nil ) {
currentController = currentController.presentedViewController
}
return currentController
}
return nil
}
Now your didSelectRowAt
code will look like this
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let storyboard : UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
if let detailViewController = storyboard.instantiateViewController(withIdentifier: "PictureDetailView") as? PictureDetailViewController
detailViewController.selectedImgName = pictureModels[indexPath.row].pictureName
self.getCurrentViewController()!.pushViewController(detailViewController, animated: true)
}
You are trying to adhere to MVC, but you are confusing what your actual data source is.
PicturesDataSource
is not your data source . It's the code that tells your table how to set itself up.
PictureModelsDataController()
is the source from which you get the data that actually populates that table.
All of your posted code should be in the same class:
class PictureTableViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
Change these lines:
pictureTableView.dataSource = picsDataSource
pictureTableView.delegate = picsDataSource
to
pictureTableView.dataSource = self // Note use of self because this is now the dataSource, not another class
pictureTableView.delegate = self // Note use of self because this is now the delegate, not another class
and remove:
private let picsDataSource: PicturesDataSource
required init?(coder aDecoder: NSCoder) {
self.picsDataSource = PicturesDataSource()
super.init(coder: aDecoder)
}
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