Firebase - iOs: How to pass data from Tableview to DetailsView? - ios

Question

I have a controller "Feed" which lists multiple posts via a table (a title and image) from Firebase.
On touch of a button, it brings to a "Feed Details" controller, where I would like the data (title image and caption) from the post clicked previously (parent) being display. (see screenshot 2)
At the moment On Click, I just got static information, none of the information are being fetch from Firebase. They are all being called correctly in the main screen, however. So the problem is when it segue to the "DetailsController"
How is it possible to fetch the details from the item click previously ??
Currently this is my feed controller:
//
// Feed.swift
// MobileAppDemo
//
// Created by Mikko Hilpinen on 31.10.2016.
// Copyright © 2016 Mikkomario. All rights reserved.
//
import UIKit
import FirebaseAuth
import FirebaseDatabase
import FirebaseStorage
import SwiftKeychainWrapper
import SwiftyJSON
class FeedVC: UIViewController, UITableViewDataSource, UIImagePickerControllerDelegate, UINavigationControllerDelegate
{
#IBOutlet weak var addImageView: UIImageView!
#IBOutlet weak var feedTableView: UITableView!
#IBOutlet weak var titleInputView: InputTextView!
#IBOutlet weak var linkbutton: UIButton!
#IBOutlet weak var captionInputView: InputTextView!
private var posts = [Post]()
private var imagePicker = UIImagePickerController()
private var imageSelected = false
private var readPosts: ObserveTask?
override func viewDidLoad()
{
super.viewDidLoad()
imagePicker.delegate = self
imagePicker.allowsEditing = true
feedTableView.dataSource = self
feedTableView.rowHeight = UITableViewAutomaticDimension
feedTableView.estimatedRowHeight = 320
readPosts = Post.observeList(from: Post.parentReference.queryOrdered(byChild: Post.PROPERTY_CREATED))
{
posts in
self.posts = posts.reversed()
self.feedTableView.reloadData()
}
}
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
// here you need to add
{
if let cell = tableView.dequeueReusableCell(withIdentifier: "MessageCell", for: indexPath) as? MessageCell
{
let post = posts[indexPath.row]
cell.configureCell(tableView: tableView, post: post)
cell.linkbutton.tag = indexPath.row
cell.linkbutton.addTarget(self, action: #selector(FeedVC.toFeedDetailAction(_:)), for: .touchUpInside)
return cell
}
else
{
fatalError()
}
}
func toFeedDetailAction(_ sender: UIButton) {
let FeedDetailsController = self.storyboard?.instantiateViewController(withIdentifier: "FeedDetailsController") as! FeedDetailsController
FeedDetailsController.post = posts[sender.tag]
self.navigationController?.pushViewController(FeedDetailsController, animated: true)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any])
{
if let image = info[UIImagePickerControllerEditedImage] as? UIImage
{
addImageView.image = image
imageSelected = true
}
picker.dismiss(animated: true, completion: nil)
}
#IBAction func selectImagePressed(_ sender: AnyObject)
{
present(imagePicker, animated: true, completion: nil)
}
#IBAction func postButtonPressed(_ sender: AnyObject)
{
guard let caption = captionInputView.text, !caption.isEmpty else
{
// TODO: Inform the user
print("POST: Caption must be entered")
return
}
guard let title = titleInputView.text, !title.isEmpty else
{
// TODO: Inform the user
print("POST: title must be entered")
return
}
guard let image = addImageView.image, imageSelected else
{
print("POST: Image must be selected")
return
}
guard let currentUserId = User.currentUserId else
{
print("POST: Can't post before logging in")
return
}
imageSelected = false
addImageView.image = UIImage(named: "add-image")
captionInputView.text = nil
titleInputView.text = nil
// Uploads the image
if let imageData = UIImageJPEGRepresentation(image, 0.2)
{
let imageUid = NSUUID().uuidString
let metadata = FIRStorageMetadata()
metadata.contentType = "image/jpeg"
Storage.REF_POST_IMAGES.child(imageUid).put(imageData, metadata: metadata)
{
(metadata, error) in
if let error = error
{
print("STORAGE: Failed to upload image to storage \(error)")
}
if let downloadURL = metadata?.downloadURL()?.absoluteString
{
// Caches the image for faster display
Storage.imageCache.setObject(image, forKey: downloadURL as NSString)
print("STORAGE: Successfully uploaded image to storage")
_ = Post.post(caption: caption, title: title, imageUrl: downloadURL, creatorId: currentUserId)
}
}
}
}
#IBAction func signOutButtonPressed(_ sender: AnyObject)
{
// Doesn't listen to posts anymore
readPosts?.stop()
try! FIRAuth.auth()?.signOut()
User.currentUserId = nil
dismiss(animated: true, completion: nil)
}
}
and my Feed Details:
//
// FeedDetails.swift
// MobileAppDemo
//
// Created by Mikko Hilpinen on 31.10.2016.
// Copyright © 2016 Mikkomario. All rights reserved.
//
import UIKit
import FirebaseAuth
import FirebaseDatabase
import FirebaseStorage
import SwiftKeychainWrapper
import SwiftyJSON
class FeedDetailsController: UIViewController, UITableViewDataSource, UIImagePickerControllerDelegate, UINavigationControllerDelegate
{
#IBOutlet weak var addImageView: UIImageView!
#IBOutlet weak var feedTableView: UITableView!
#IBOutlet weak var titleInputView: InputTextView!
#IBOutlet weak var linkbutton: UIButton!
#IBOutlet weak var captionInputView: InputTextView!
var post: Post!
private var posts = [Post]()
private var imagePicker = UIImagePickerController()
private var imageSelected = false
private var readPosts: ObserveTask?
override func viewDidLoad()
{
super.viewDidLoad()
imagePicker.delegate = self
imagePicker.allowsEditing = true
readPosts = Post.observeList(from: Post.parentReference.queryOrdered(byChild: Post.PROPERTY_CREATED))
{
posts in
self.posts = posts.reversed()
}
}
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
// here you need to add
{
if let cell = tableView.dequeueReusableCell(withIdentifier: "MessageCell", for: indexPath) as? MessageCell
{
let post = posts[indexPath.row]
cell.configureCell(tableView: tableView, post: post)
cell.linkbutton.tag = indexPath.row
cell.linkbutton.addTarget(self, action: #selector(FeedVC.toFeedDetailAction(_:)), for: .touchUpInside)
return cell
}
else
{
fatalError()
}
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any])
{
if let image = info[UIImagePickerControllerEditedImage] as? UIImage
{
addImageView.image = image
imageSelected = true
}
picker.dismiss(animated: true, completion: nil)
}
#IBAction func selectImagePressed(_ sender: AnyObject)
{
present(imagePicker, animated: true, completion: nil)
}
#IBAction func postButtonPressed(_ sender: AnyObject)
{
guard let caption = captionInputView.text, !caption.isEmpty else
{
// TODO: Inform the user
print("POST: Caption must be entered")
return
}
guard let title = titleInputView.text, !title.isEmpty else
{
// TODO: Inform the user
print("POST: title must be entered")
return
}
guard let image = addImageView.image, imageSelected else
{
print("POST: Image must be selected")
return
}
guard let currentUserId = User.currentUserId else
{
print("POST: Can't post before logging in")
return
}
imageSelected = false
addImageView.image = UIImage(named: "add-image")
captionInputView.text = nil
titleInputView.text = nil
// Uploads the image
if let imageData = UIImageJPEGRepresentation(image, 0.2)
{
let imageUid = NSUUID().uuidString
let metadata = FIRStorageMetadata()
metadata.contentType = "image/jpeg"
Storage.REF_POST_IMAGES.child(imageUid).put(imageData, metadata: metadata)
{
(metadata, error) in
if let error = error
{
print("STORAGE: Failed to upload image to storage \(error)")
}
if let downloadURL = metadata?.downloadURL()?.absoluteString
{
// Caches the image for faster display
Storage.imageCache.setObject(image, forKey: downloadURL as NSString)
print("STORAGE: Successfully uploaded image to storage")
_ = Post.post(caption: caption, title: title, imageUrl: downloadURL, creatorId: currentUserId)
}
}
}
}
#IBAction func signOutButtonPressed(_ sender: AnyObject)
{
// Doesn't listen to posts anymore
readPosts?.stop()
try! FIRAuth.auth()?.signOut()
User.currentUserId = nil
dismiss(animated: true, completion: nil)
}
}

Answer 1

You need to implement prepare(for:sender:) in your table view (a UITableViewDelegate method) and add the data you need to display to your detail view controller there.

Answer 2

Okay, I tried using your code but there are so many missing elements that it was returning errors so I don't know if this will compile but it should do.
First:
I assume the the private var posts = [Post]() in both classes hold the same value of the posts
Second:
you need to add UITableViewDelegate to your superclass
class FeedVC: UIViewController, UITableViewDataSource, UITableViewDelegate, ...
Third:
add the following in your FeedVC:
private var selectedIndexPath: Int = 0
and this in your FeedDetailsController
var selectedIndexPath: Int = 0 // cannot be private to get accessed from FeedVC
and this Delegate function in FeedVC:
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
selectedIndexPath = indexPath.row
}
and the prepare for segue in FeedVC:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let newViewController = segue.destination as! FeedDetailsController
newViewController.selectedIndexPath = selectedIndexPath
}
Lastly you can now use the selectedIndexPath within posts to get the chosen post
let post = posts[selectedIndexPath]
Hope This Helps!