How can I pass a Post Id to a Comments VC - Swift - swift

Question

I am having trouble sending the postid to comments vc so that I can save it in Firebase.
I am following a tutorial online where we are building this architecture on Firebase however when I send the data to Firebase it is not capturing the postId as seen onthis screenshot. I'm obviously missing something. Would really appreciate it if someone could shed some light as to what my mistake could be. Below I'll put the Comments View Controller function where I send the data to Firebase.
#IBAction func sendButtonPressed(_ sender: UIButton) {
let ref = Database.database().reference()
let commentsReference = ref.child("comments")
let newCommentId = commentsReference.childByAutoId().key
let newCommentReference = commentsReference.child(newCommentId)
//current user information
guard let currentUser = Auth.auth().currentUser else {
return
}
let currentUserId = currentUser.uid
newCommentReference.setValue(["userid": currentUserId, "commentText": commentTextField.text!]) { (error, ref) in
if error != nil {
ProgressHUD.showError(error!.localizedDescription)
return
}
let postCommentRef = Database.database().reference().child("post-comments").child(self.postIdNew).child(newCommentId)
postCommentRef.setValue(true, withCompletionBlock: { (error, ref) in
if error != nil {
ProgressHUD.showError(error!.localizedDescription)
return
}
})
self.empty()
self.view.endEditing(true)
}
}
This is how I'm supposed to get the postId reference from the Home View Controller.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "commentSegue" {
let commentVC = segue.destination as! CommentViewController
let postId = sender as! String
commentVC.postIdNew = postId
}
}
Here are my collection view extensions
extension HomeViewController: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if collectionView == self.lostCollectionView {
return posts.count
}
if collectionView == self.foundCollectionView {
return newPostsFound.count
}
if collectionView == self.adoptionCollectionView {
return postsadoption.count
}
else {
return 0
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
switch collectionView {
case lostCollectionView:
let lostcell: LostCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Lostcell", for: indexPath) as! LostCollectionViewCell
let post = posts[indexPath.row]
let user = users[indexPath.row]
lostcell.post = post
lostcell.user = user
//Make TextView Clickable
lostcell.phoneLostTextView.isEditable = false;
lostcell.phoneLostTextView.dataDetectorTypes = UIDataDetectorTypes.phoneNumber
//Make Comments View Clickable
lostcell.homeVC = self
return lostcell
case foundCollectionView:
let foundcell: FoundCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Foundcell", for: indexPath) as! FoundCollectionViewCell
let post = newPostsFound[indexPath.row]
foundcell.post = post
//Make TextView Clickable
foundcell.phoneFoundTextView.isEditable = false;
foundcell.phoneFoundTextView.dataDetectorTypes = UIDataDetectorTypes.phoneNumber
return foundcell
case adoptionCollectionView:
let adoptioncell: AdoptionCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "Adopotioncell", for: indexPath) as! AdoptionCollectionViewCell
let post = postsadoption[indexPath.row]
adoptioncell.post = post
//Make TextView Clickable
adoptioncell.phoneAdoptionTextView.isEditable = false;
adoptioncell.phoneAdoptionTextView.dataDetectorTypes = UIDataDetectorTypes.phoneNumber
return adoptioncell
default:
return UICollectionViewCell()
}
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
switch collectionView {
case lostCollectionView:
let vc = storyboard?.instantiateViewController(withIdentifier: "lostSelectedViewController") as? LostSelectedViewController
self.navigationController?.pushViewController(vc!, animated: true)
vc?.posts = posts[indexPath.row]
break
case foundCollectionView:
let vc = storyboard?.instantiateViewController(withIdentifier: "foundSelectedViewController") as? FoundSelectedViewController
self.navigationController?.pushViewController(vc!, animated: true)
vc?.posts = newPostsFound[indexPath.row]
break
case adoptionCollectionView:
let vc = storyboard?.instantiateViewController(withIdentifier: "adoptionSelectedViewController") as? AdoptionSelectedViewController
self.navigationController?.pushViewController(vc!, animated: true)
vc?.posts = postsadoption[indexPath.row]
break
default:
break
}
func commentsViewPressed() {
print("Hola")
performSegue(withIdentifier: "commentSegue", sender: self)
}
}
}

Answer 1

The issue looks like its in this code
let postId = sender as! String
commentVC.postIdNew = postId
Sender refers to the object that initiated the segue, so likely a button or TableViewCell (see apples docs: https://developer.apple.com/documentation/uikit/uiviewcontroller/1621490-prepare)
You need to replace sender as! String with the value of the postId that you are trying to set. I assume that you can get that from somewhere on the first view controller.

Answer 2

Actually my mistake was nowhere here. My mistake was that my snapshot.key was not retreiving the childByAutoId so when I ran the query it gave me a list of matching children and since there was no single result, the SDK prints the key of the location/collection that you queried: posts.
All I had to do was to retrieve the childByAutoId I had to use this line:
let key = childSnapshot.key as String
I found my answer in this stackoverflow question --> Firebase snapshot.key not returning actual key?