iOS + Firebase - Send data from view controller to detail view controller - ios

Question

I have a ViewController, where a list of data is being fetched from the RealtimeDatabase and being displayed in the UITableView. When a post is clicked, I want the data from the ViewController such as Title, Description, and Image to be carried forward into a DetailView i.e: PostController.Swift where I can further call more data from the RealtimeDatabase to be displayed in the PostController.Swift
I tried to use didSelectRowAt but was unable to fetch and display data in the PostController, I'm also currently trying to use prepare but getting stuck at the same place.
Here is the ViewController.Swift:
import UIKit
import Firebase
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var tableView:UITableView!
var posts = [Post]()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
tableView = UITableView(frame: view.bounds, style: .plain)
view.addSubview(tableView)
let cellNib = UINib(nibName: "PostTableViewCell", bundle: nil)
tableView.register(cellNib, forCellReuseIdentifier: "postCell")
var layoutGuide:UILayoutGuide!
layoutGuide = view.safeAreaLayoutGuide
tableView.leadingAnchor.constraint(equalTo: layoutGuide.leadingAnchor).isActive = true
tableView.topAnchor.constraint(equalTo: layoutGuide.topAnchor).isActive = true
tableView.trailingAnchor.constraint(equalTo: layoutGuide.trailingAnchor).isActive = true
tableView.bottomAnchor.constraint(equalTo: layoutGuide.bottomAnchor).isActive = true
tableView.delegate = self
tableView.dataSource = self
tableView.tableFooterView = UIView()
tableView.reloadData()
observePosts()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func observePosts() {
let postsRef = Database.database().reference().child("Data")
postsRef.observe(.value, with: { snapshot in
var tempPosts = [Post]()
for child in snapshot.children{
if let childSnapshot = child as? DataSnapshot,
let dict = childSnapshot.value as? [String:Any],
let title = dict["title"] as? String,
let logoImage = dict["image"] as? String,
let url = URL(string:logoImage),
let description = dict["description"] as? String{
let userProfile = UserProfile(title: title, photoURL: url)
let post = Post(id: childSnapshot.key, title: userProfile, description: description, image: userProfile)
print(post)
tempPosts.append(post)
}
}
self.posts = tempPosts
self.tableView.reloadData()
})
}
func getImage(url: String, completion: #escaping (UIImage?) -> ()) {
URLSession.shared.dataTask(with: URL(string: url)!) { data, response, error in
if error == nil {
completion(UIImage(data: data!))
} else {
completion(nil)
}
}.resume()
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return posts.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
let cell = tableView.dequeueReusableCell(withIdentifier: "postCell", for: indexPath) as! PostTableViewCell
cell.set(post: posts[indexPath.row])
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
tableView.estimatedRowHeight = 50
return UITableViewAutomaticDimension
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "PostDetailSegue" {
if let indexPaths = self.tableView!.indexPathForSelectedRow{
}
}
}
}

Answer 1

You need to store a reference to the Post in your DetailViewController.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "PostDetailSegue" {
let detailViewController = segue.destinationViewController as! DetailViewController
let indexPath = tableView.indexPathForSelectedRow
let post = posts[indexPath.row]
detailViewController.setPost(post)
}
}
And in your DetailViewController:
func detailViewController.setPost(_ post: Post) {
// Store the post and fetch other data as necessary
self.post = post
}

Answer 2

try this one.
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let postsInfo = posts[indexPath.row]
print(postsInfo)
performSegueWithIdentifier("PostDetailSegue", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "PostDetailSegue" {
if let indexPaths = posts[indexPath.row]{
//add parmaters which passed to another viewcontroller
}
}
}