Pass data from collectionCell inside tableCell to secondVC use protocol - ios

Question

I have two viewController's. The first VC has collectionCell inside tableCell. The second VC has collectionCell, and I have swift File with Model have a class. I need to pass data from the first VC (collectionCell) to the second VC.
Pass data need from collectionCell because collectionCell has images (from swift File - Model). I think need use a protocol, but I don't really understand how to work with a protocol. Please help.
My code:
1stVC(viewController):
class ViewController1: UIViewController {
#IBOutlet weak var tableView: UITableView!
var image: [Model] = []
var ref: FIRDatabaseReference!
override func viewDidLoad() {
super.viewDidLoad()
ref = FIRDatabase.database().reference(withPath: "Студии2")
ref.observe(.value, with: { (snapshot) in
var newImages: [Model] = []
for item in snapshot.children {
let object = Model(snapshot: item as! FIRDataSnapshot)
newImages.append(object)
}
self.image = newImages
self.tableView.reloadData()
})
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
extension ViewController1: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return image.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell1
cell.images = [image[indexPath.row].image,
image[indexPath.row].image2]
return cell
}
}
1stVC(collectionCell inside tableCell):
protocol PostDelegate {
func selectedPost(cell: String)
}
class TableViewCell1: UITableViewCell {
var images = [String]()
var selecetdItem: Model?
var postDelegate: PostDelegate?
}
extension TableViewCell1: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return images.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! CollectionViewCell1
cell.imagesView.sd_setImage(with: URL(string: images[indexPath.item]))
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
postDelegate?.selectedPost(cell: self.images[indexPath.item])
print(images[indexPath.item])
}
}
2ndVC(viewController):
class ViewController3: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!
// var images = [String]()
var images: [Model] = []
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
extension ViewController3: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return images.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! CollectionViewCell3
// let array = [images[indexPath.item].images,
// images[indexPath.item].images2]
// cell.imagesView.sd_setImage(with: URL(string: array[indexPath.item]))
// cell.imagesView.sd_setImage(with: URL(string: images[indexPath.item]))
return cell
}
}
Model(swift File have a class):
class Model {
var image: String!
var image2: String!
var images: [String] = []
var images2: [String] = []
var ref: FIRDatabaseReference!
init(snapshot: FIRDataSnapshot) {
ref = snapshot.ref
let value = snapshot.value as! NSDictionary
let snap1 = value["hall1"] as? NSDictionary
let snap2 = value["hall2"] as? NSDictionary
image = snap1?["qwerty"] as? String ?? ""
image2 = snap2?["qwerty"] as? String ?? ""
if let post1 = snap1 as? [String: AnyObject] {
for (_, value) in post1["images"] as! [String: AnyObject] {
self.images.append(value as! String)
}
}
if let post1 = snap1 as? [String: AnyObject] {
for (_, value) in post1["images"] as! [String: AnyObject] {
self.images2.append(value as! String)
}
}
}
}

Answer 1

Pass ViewController1 as the postDelegate of TableViewCell1
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell1
//make VC1 as post delegate of cell
(cell as! TableViewCell1).postDelegate = self
cell.images = [image[indexPath.row].image,
image[indexPath.row].image2]
return cell
}
Finally implement
extension ViewController1 : PostDelegate {
func selectedPost(cell: String) {
//call self.perform segue or load VC2 and pass data here
}
}
Pinch of Advice :
var postDelegate: PostDelegate?
will result in strongly holding a reference to the delegate being passed. Which will result in memory leaks. To make it safer declare delegate as weak
weak var postDelegate: PostDelegate?
In order to make the Protocol weak your protocol
protocol PostDelegate: NSObjectProtocol {
func selectedPost(cell: String)
}