Are there different solution how retrieve waypoints? - swift

Question

"-KHbCuQflKHrJiUmfpG0" : {
"waypoints" : {
"-KHbCuQflKHrJiUmfpG1" : {
"latitude" : 13.17078652595298,
"longitude" : -59.5775944578738
},
"-KHbCuQflKHrJiUmfpG2" : {
"latitude" : 13.15541190861343,
"longitude" : -59.57619643155932
},
"-KHbCuQg9W_tebl1pU66" : {
"latitude" : 13.148444967591,
"longitude" : -59.5589266947333
}
},
"subtitle" : "jamesrick",
"title" : "Highway",
"type" : "polyline"
},
I have this structure for lines in Firebase. How retrieve all data with also nested node waypoints?
ref.observeEventType(.Value, withBlock: { polylines in
if let objects = polylines.children.allObjects as? [FDataSnapshot] {
for object in objects {
polylineDictionary = object.values as? Dictionary<String, AnyObjects> {
// ? ? ?
}
}
}
})
Now I have access to title, subtitle, type but how obtain access to waypoints? When I use
`polylineDictionary["waypoints"] as? [String: [String:Double]]`
so this dictionaries are not ordered. Thanks for some advice.

Answer 1

This is how I would get the nested waypoints... it's basically by iterating through the keys... I would also add some error checking when grabbing the longitude and latitudes to make sure they're there, but this is the gist:
if let polylineDictionary["waypoints"] as? [String: [String:Double]] {
let waypoints = Array(polylineDictionary.keys)
for i in 0..<waypoints.count {
let waypointId = waypoints[i]
let latitude = polylineDictionary[waypointId]["latitude"]
let longitutde = polylineDictionary[waypointId]["longitude"]
}
}

Answer 2

It's not clear from the question about ordering; if you just want to get to the waypoints, it's pretty straight forward:
Assume your complete Firebase structure is:
root_node
"-KHbCuQflKHrJiUmfpG0" : {
"waypoints" : {
"-KHbCuQflKHrJiUmfpG1" : {
"latitude" : 13.17078652595298,
"longitude" : -59.5775944578738
},
"-KHbCuQflKHrJiUmfpG2" : {
"latitude" : 13.15541190861343,
"longitude" : -59.57619643155932
},
"-KHbCuQg9W_tebl1pU66" : {
"latitude" : 13.148444967591,
"longitude" : -59.5589266947333
}
},
"subtitle" : "jamesrick",
"title" : "Highway",
"type" : "polyline"
}
Suppose I want the data for this specific node, -KHbCuQflKHrJiUmfpG0
let nodeRef = rootRef.childByAppendingPath("-KHbCuQflKHrJiUmfpG0")
nodeRef.observeSingleEventOfType(.Value , withBlock: { snapshot in
print(snapshot.value) //prints everything in the node
let title = snapshot.value["title"] as! String //to get any element
print(title) //prints Highway
var waypoints = [String: [String:String]]() //dict to hold key:value, unordered
waypoints = snapshot.value["waypoints"] as! Dictionary
print(waypoints) //prints the 3 waypoints and their children (as a dict)
//get fancy and convert the dictionary to an array (which can be sorted)
let arr = waypoints.map {"\($0) \($1)"}
for point in arr {
print(point)
}
}