Passing a variable from a UIImagePickerController to other functions in Swift - swift

Question

I have an issue I'm trying to figure out. I'm not sure what an "elegant" way to approach this would be. This is my first Swift project, so excuse me if I'm asking something ridiculous.
I have this controller/image picker to get me the latitude/longitude of a photo in a user's photo library.
//Get metadata from a photo. Save location (latitude/longitude)
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
let picker = UIImagePickerController()
picker.delegate = self // delegate added
if let URL = info[UIImagePickerControllerReferenceURL] as? URL {
print("We got the URL as \(URL)")
let opts = PHFetchOptions()
opts.fetchLimit = 1
let assets = PHAsset.fetchAssets(withALAssetURLs: [URL], options: opts)
for assetIndex in 0..<assets.count {
var asset = assets[assetIndex]
var location = String(describing: asset.location!)
var photo_latitude = asset.location?.coordinate.latitude
var photo_longitude = asset.location?.coordinate.longitude
var coords : [String: Double] = ["longitude": photo_longitude!, "latitude": photo_latitude!]
PHAsset.fetchAssets(withALAssetURLs: [URL], options: nil)
dismiss(animated:true, completion: nil)
PHImageManager.default()
.requestImageData(for: asset,
options: nil) { resultData, response, orientation, info in
var data = resultData
DropboxClientsManager
.authorizedClient?
.files
.upload(path: "/development/image.jpg", mode: .overwrite, input : data!)
print(data!)
}
}
}
}
}
I'm also uploading the image they select to Dropbox.
Here's my issue. I want to get the address from the latitude and longitude, but I need some way to pass the latitude and longitude into the appropriate function. I'm using the following code with the Google Maps API to find an address from latitude and longitude.
let baseUrl = "http://maps.googleapis.com/maps/api/geocode/json?latlng=40.714224,-73.961452&sensor=true/false"
let apikey = "hiding_my_api_key"
func getAddressFromGoogle() {
Alamofire.request(baseUrl, method: .get).responseJSON {
response in
if response.result.isSuccess {
print("Successful request.")
var locationData = JSON(response.result.value!)
let streetAddress = locationData["results", 0, "formatted_address"]
print(streetAddress)
print(locationData)
}
else {
print("Error \(response.result.error)")
}
}
}
What would be the best way for me to pass photo_longitude and photo_latitude to my getAddressFromGoogle function?
Thanks in advance.

Answer 1

The typical Swift way to approach this would be to attack it head on. Latitude and longitude are both floating point numbers, and you would usually pass them as such:
func getAddressFrom(lat: Double, long: Double)
Once inside the getAddressFrom(_:_:) method, you would typically use an instance of number formatter to convert each Double to a String of the format Google’s API expects:
func getAddressFrom(lat: Double, long: Double) {
let baseUrl = "http://maps.googleapis.com/maps/api/geocode/json?", urlSuffix = "&sensor=true/false"
let numberFormatter = NumberFormatter()
numberFormatter.maximumFractionDigits = 6
// Do other configuration to get the number formatter to produce the output you need…
let numberLat = NSNumber(floatLiteral: lat), numberLong = NSNumber(floatLiteral: long)
guard let textLat = numberFormatter.string(from: numberLat),
let textLong = numberFormatter.string(from: numberLong) else {
// Handle invalid latitude or longitude…
return
}
let completeUrl = baseUrl + textLat + "," + textLong + urlSuffix
// Remaining body of function…
}
In production, you would probably configure the number formatter in the class body to reuse for many images.
Looking at your image picker controller, I see the latitude and longitude you are pulling off the images are optional values, since they may or may not be nil. When calling getAddressFrom(_:_:), you would probably use optional binding to unwrap the optionals and handle the nil case:
guard let photo_latitude = photo_latitude, let photo_longitude = photo_longitude else {
// Handle a photo missing latitude, longitude, or both…
return
}
getAddressFrom(lat: photo_latitude, long: photo_longitude)
Note that it is uncommon to use underscores in variable names in Swift. photoLatitude and photoLongitude are more Swift-y.