I'm using the new Google Firebase database in my iOS (Swift) app.
When the user create an account, he is added to the database with some parameters like his name, his age, and mostly his current location (latitude / longitude).
I would like the app to find other users within XXkm around him.
I created the test users like this :
for index in 1...10 {
let profile: NSMutableDictionary = [
"username" : "User\(index)",
]
let parameters = [ // IT IS PARIS LOCATION
"latitude" : 48.856614,
"longitude" : 2.352222
]
self.ref.child("usersTest").child("userID:\(index)").child("profile").setValue(profile)
self.ref.child("usersTest").child("userID:\(index)").child("parameters").setValue(parameters)
}
This is how I proceed :
// MARK: GET RANDOM USER
refHandle = ref.observeEventType(FIRDataEventType.Value, withBlock: { (snapshot) in
// IN THE DATABASE, I MODIFY THE USER 1 TO BE MY OWN ACCOUNT,
// SO I CHANGE THE LOCATION TO BE DIFFERENT FROM THE OTHER
// USERS LOCATION
let ownUserID = "userID:1"
let usersDict = snapshot.value!["usersTest"] as! NSDictionary
let ownLatitude = usersDict[ownUserID]!["parameters"]!!["latitude"] as! CLLocationDegrees
let ownLongitude = usersDict[ownUserID]!["parameters"]!!["longitude"] as! CLLocationDegrees
let ownMaxDistance = usersDict[ownUserID]!["parameters"]!!["max_distance"] as! CLLocationDegrees
self.myLocation = CLLocation(latitude: ownLatitude, longitude: ownLongitude)
let usersID = usersDict.allKeys as! [String]
for index in 0...usersID.count - 1 {
let foundUserID = usersID[index]
if foundUserID != ownUserID {
let users = usersDict[foundUserID] as! NSDictionary
self.usersArray["user\(index)"] = users
let userParameters = self.usersArray["user\(index)"]!["parameters"] as! NSDictionary
let latitude = userParameters["latitude"] as! CLLocationDegrees
let longitude = userParameters["longitude"] as! CLLocationDegrees
let userLocation = CLLocation(latitude: latitude, longitude: longitude)
let distance = self.getDistance(userLocation, city2: self.myLocation)
if distance < ownMaxDistance {
print("The user is inside your radius")
} else {
print("The user is outside your radius")
}
}
}
})
// MARK: GET DISTANCE - FUNCTION
func getDistance(city1: CLLocation, city2: CLLocation) -> CLLocationDegrees {
let distance: CLLocationDistance = (city1.distanceFromLocation(city2)) / 1000
return distance
}
The problem with this way is that all the database is loaded because the app load the database, and then it check if the found user is inside or outside your radius (ownMaxDistance).
I do not know how to classify found users in ascending order based on the distance between the found user and the user.
With 100/200 users in the database there is no problem, but if the database hold thousands of users, it will be very long to load all the users!
Thanks for your help !
UPDATE 1
To be clear, it is a Tinder like app
