How to retrieve image from firebase storage Swift 4 ios - ios

Question

I am trying to retrieve an image from firebase storage but the image that I retrieve always is nil for some reason.
var ref: DatabaseReference!
var storageRef: StorageReference!
var hallData = [Hall]()
override func viewDidLoad() {
let refHandle = Database.database().reference().child("hallData").observe(DataEventType.value, with: { (snapshot) in
let postDict = snapshot.value as? [String : AnyObject] ?? [:]
 let values = Array(postDict.values)
//print(values)
let valueDict = values as! [[String:Any]]
for i in valueDict
{
var name = i["name"] as! String
var address = i["address"] as! String
var capacity = i["capacity"] as! String
var decorations = i["decorations"] as! String
var highPrice = i["highPrice"] as! String
var lowPrice = i["lowPrice"] as! String
var catering = i["catering"] as! String
var email = i["email"] as! String
self.storageRef = Storage.storage().reference().child("images").child(email)
var image: UIImage!
// Download in memory with a maximum allowed size of 1MB (1 * 1024 * 1024 bytes)
self.storageRef.getData(maxSize: 1 * 1024 * 1024) { data, error in
if let error = error {
print("PLASESEE")
print(error.localizedDescription)
// Uh-oh, an error occurred!
} else {
// Data for "images/island.jpg" is returned
let image = UIImage(data: data!)
}
}
print(image)
self.hallData.append(Hall(name2: name, capacity2: capacity, lowPrice2: lowPrice, highPrice2: highPrice, catering2: catering,decorations2: decorations, address2:address, image2: image, email2: email))
}
})
}
I dont understand what I am doing wrong, I followed the api on firebase storage, checked out a lot of tutorials but I keep getting nil

Answer 1

The issue is that you're attempting to work with the image var outside the getData closure.
self.storageRef.getData(maxSize: 1 * 1024 * 1024) { data, error in
if let error = error {
print("PLASESEE")
print(error.localizedDescription)
// Uh-oh, an error occurred!
} else {
// Data for "images/island.jpg" is returned
let image = UIImage(data: data!)
} <- closure ends here and image is only valid above this
}
print(image) <- image may not be populated at this point
self.hallData.append... image
}
That closure is asynchronous and the call to self.hallData.append... will occur way before the image var is populated within the closure. Code is much faster than the internet
Move that statement inside the closure, right after the let image = and it should work.
self.storageRef.getData(maxSize: 1 * 1024 * 1024) { data, error in
if let error = error {
print("An error occurred in downloading the image")
print(error.localizedDescription)
} else {
let image = UIImage(data: data!)
self.hallData.append... image
//reload your tableView or UI as self.hallData is now valid
}
}
If you do it this way, the preceeding var image: UIImage! can be removed as it doesn't have a function. Otherwise, remove the let before let image = within the closure.