retrieve array elements from firebase in swift - ios

Question

I am completely new to swift and firebase, and I am having difficulties in retrieving array-elements from firebase database
So this is my firebase database
I can retrieve the other elements like this:
database reference
class ViewController: UIViewController {
var ref: FIRDatabaseReference?
let fileName : String = "jsonFile"
method
func parseFirebaseResponse() {
ref?.child("Vandreture").child(fileName).observe(.value, with:
{ (snapshot) in
let dict = snapshot.value as? [String: AnyObject]
let navn = dict!["navn"] as? String
print(navn as Any)
let type = dict!["type"] as? String
print(type as Any)
let Længde = dict!["length"] as? String
print(Længde as Any)
let link = dict!["link"] as? String
print(link as Any)
})
}
the console shows the result
But I have searched for a way to retrieve longitude/latitude pairs,
The first pair should be
latitude 109.987
longitude 102.987
- but so far without luck - help would really be appreciated :)

Answer 1

I think you should restructure your database to something like this:
Vandreture {
jsonFile {
length: "16.2"
link: "www.second.com"
navn: "Kagerup rundt"
positions {
-KqXukxnw3mL38oPeI4y {
x: "102.987"
y: "109.987"
}
-KqXukxnw3mL38oPeI5- {
x: "108.234"
y: "99.098"
}
}
}
}
Then getting your coordinates would be far easier!

Answer 2

Get your "position" as a dictionary (aka [String: AnyObject]).
Then get array of latitude and longitude. Then map of each element from latitude and longitude into a tuple or something like that.
guard let position = dict!["position"] as? [String: AnyObject],
let latitudeArray = position["latitude"] as? [String],
let longitudeArray = position["longitude"] as? [String] else { return }
print(latitudeArray)
print(longitudeArray)

Answer 3

thanks Victor Apeland - now I changed the structure of the database. I was not able to do it exactly as you suggested!!
I concatenated the lon/lat as a string (not the best - i know - I'm a newbie to swift, and firebase is not well documented)
to retrieve the individual elements from my long/lat, I used this method, and I was particular interested in the first reading, so I made a list, populated it, and got the first element, parsing it to a new method
func responsePosition() {
var positions = [String]()
ref?.child("Vandreture").child(fileName).child("position").observe(.value, with: { (snapshot) in
for snap in snapshot.children {
let userSnap = snap as! FIRDataSnapshot
let uid = userSnap.key //the uid of each user
let userDict = userSnap.value as! String
positions.append(userDict)
}
let pos : String = positions[0]
self.formatPositions(pos : pos)
})
}
In my firebase lon-lat was divided by a space, so I split the string and cast to double.
func formatPositions(pos : String) {
let lotLangDivided = pos.components(separatedBy: " ")
let longitude = Double(lotLangDivided[0])
let latitude = Double(lotLangDivided[1])
}
now I got the result i wanted
- thanks for the help Victor and Khuong :)