Send Firebase data from Main View Controller to Detailed View Controller - ios

Question

I was able to create a UICollection View feed similar to Instagram but I am not sure how to select the cells and go to a more detailed view controller. Here are what my main view controller looks like. '
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
performSegue(withIdentifier: "details", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "details" {
if let indexPaths = self.collectionView!.indexPathsForSelectedItems{
let vc = segue.destination as! MainViewController
let indexPath = indexPaths[0] as NSIndexPath
let post = self.posts[indexPath.row] as! [String: AnyObject]
let Booked = post["title"] as? String
let Authors = post["Author"] as? String
let ISBNS = post["ISBN"] as? String
let Prices = post["Price"] as? String
let imageNames = post["image"] as? String
vc.Booked = Booked
vc.Authors = Authors
vc.ISBNS = ISBNS
vc.Prices = Prices
vc.imageNames = imageNames
print(indexPath.row)
} }}
Here is what my database looks like:
//Detailed View Controller
FIRDatabase.database().reference().child("posts").child(self.loggedInUser!.uid).observeSingleEvent(of: .value, with: { (snapshot:FIRDataSnapshot) in
if let dictionary = snapshot .value as? [String: AnyObject] {
self.BookTitle.text = dictionary["title"] as? String
self.Author.text = dictionary["Author"] as? String
self.ISBN.text = dictionary["ISBN"] as? String
self.Price.text = dictionary["Price"] as? String
self.Image.image = ["image"] as? UIImage
}
})
Above is my detailed view controller. However, when I click the cells, my information is not passed

Answer 1

You need to give segue from cell instead of view.Like shown in image below
Then modify your code as shown below:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
// No Need to call this performSegue(withIdentifier: "details", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "details" {
if let indexPaths = self.collectionView!.indexPathsForSelectedItems{
let vc = segue.destination as! MainViewController
let cell = sender as UICollectionViewCell
let indexPath = self.collectionView!.indexPathForCell(cell)
let post = self.posts[indexPath.row] as! [String: AnyObject]
let Booked = post["title"] as? String
let Authors = post["Author"] as? String
let ISBNS = post["ISBN"] as? String
let Prices = post["Price"] as? String
let imageNames = post["image"] as? String
vc.Booked = Booked
vc.Authors = Authors
vc.ISBNS = ISBNS
vc.Prices = Prices
vc.imageNames = imageNames
print(indexPath.row)
} }}
then in DetailsViewController code will be like below (no need to reference firebase again as you already have all info) :
self.BookTitle.text = self.Booked
self.Author.text = self.Author
self.ISBN.text = self.ISBN
self.Price.text = self.Price
if let stringImage = self.imageNames as? String {
let imageRef = storage.reference(forURL: "gs://gsignme-14416.appspot.com/images/\(stringImage)")
imageRef.data(withMaxSize: 25 * 1024 * 1024, completion: { (data, error) -> Void in
if error == nil {
self.Image.image = UIImage(data: data!)
}else {
print("Error downloading image:" )
}
Write code in viewDidLoad.

Answer 2

This seems to be a duplicate. A great example of passing data between view controllers can be found here: Passing Data between View Controllers.
Structuring your data is also important. If you have a Post object received from your Firebase Database, you should create a local Post object and reference that. On the UICollectionViewCell, you can use the selected indexPath to get the Post designated to that cell.

Answer 3

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "details" {
if let indexPaths = self.collectionView!.indexPathsForSelectedItems{
let vc = segue.destination as! MainViewController
let cell = sender as! UICollectionViewCell
let indexPath = self.collectionView!.indexPath(for: cell)
let post = self.posts[(indexPath?.row)!] as! [String: AnyObject]
let Booked = post["title"] as? String
let Authors = post["Author"] as? String
let ISBNS = post["ISBN"] as? String
let Prices = post["Price"] as? String
if let imageNames = post["image"] as? String {
let imageRef = storage.reference(forURL: "gs://gsignme-14416.appspot.com/images/")
imageRef.data(withMaxSize: 25 * 1024 * 1024, completion: { (data, error) -> Void in
if error == nil {
let image = UIImage(data: data!)
}else {
print("Error downloading image:" )
}
vc.Booked = Booked
vc.Authors = Authors
vc.ISBNS = ISBNS
vc.Prices = Prices
vc.imageNames = imageNames
print(indexPath?.row)
})} } }}