Can't get app to display cryptocurrency amount - iphone

Question

From "var myValue:[Double]..." and "var activeCurrency:Double = 0;" to the third pickerview code, I am not sure what to do in order to fix the "self.myValues.append((Url as? Double)!)" so that my app displays the currency amount. I have searched everywhere, and have no luck in finding anything. You are my last hope, please help. I'm still fairly new to coding, so I may not know the certain jargon.
import UIKit
class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var myCurrency:[String] = []
var myValues:[Double] = []
var activeCurrency:Double = 0;
//OBJECTS
#IBOutlet weak var textbox: UITextField!
#IBOutlet weak var pickerView: UIPickerView!
#IBOutlet weak var output: UILabel!
//CREATING PICKER VIEW
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return myCurrency.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return myCurrency[row]
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
activeCurrency = myValues[row]
}
//BUTTON
#IBAction func action(_ sender: AnyObject) {
if (textbox.text != "") {
output.text = String(Double(textbox.text!)! * activeCurrency)
}
}
override func viewDidLoad() {
super.viewDidLoad()
//DATA GRABBING
let url = URL(string: "https://min-api.cryptocompare.com/data/all/coinlist")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error != nil {
print ("ERROR")
}
else {
if let content = data {
do {
let myJson = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
if let rates = myJson["Data"] as? NSDictionary {
for (Name, Url) in rates {
self.myCurrency.append((Name as? String)!)
self.myValues.append((Url as? Double)!)
}
}
}
catch {
}
}
}
if data != nil {
DispatchQueue.main.async { // Correct
self.pickerView.reloadAllComponents()
}
}
}
task.resume()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}