Swift javascript/ios bridge breaks swipe gesture recognizer - ios

Question

I have a swipe gesture recognizer to bring a toolbar off and on the screen. It was working beautifully until I added a JavaScript to iOS bridge using WKUserContentController(). The bridge works, successfully printing the JavaScript message, but swiping no longer works. But if I comment out Webview = WKWebView(frame: self.view.frame, configuration: configuration) and view.addSubview(Webview) the bridge is obviously broken, but the gesture recognizer works. I just can't get them both working at the same time. Where have I gone wrong?
Edit: Maybe this is relevant: with the code as below, the activity indicator does not appear when the WebView is loading. Also, if I comment out the lines that start the toolbar hidden (starting point swiped off the page), the toolbar should appear, but it doesn't:
import UIKit
import WebKit
import CoreLocation
class ViewController: UIViewController, CLLocationManagerDelegate,
WKNavigationDelegate, WKScriptMessageHandler {
let locationManager = CLLocationManager()
#IBOutlet var Webview: WKWebView!
#IBOutlet var ActInd: UIActivityIndicatorView!
#IBOutlet var Toolbar: UIToolbar!
override func viewDidLoad() {
super.viewDidLoad()
let controller = WKUserContentController()
controller.add(self, name: "SwiftNative")
let configuration = WKWebViewConfiguration()
configuration.userContentController = controller
// commenting out these two lines disables the bridge but activates swiping again
Webview = WKWebView(frame: self.view.frame, configuration: configuration)
view.addSubview(Webview)
let url = URL(string: "https://www.bazleysawesomesite.com")
let request = URLRequest(url: url!)
Webview.load(request)
self.locationManager.delegate = self
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
self.locationManager.requestWhenInUseAuthorization()
let rightSwipe = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.handleSwipes(_:)))
let leftSwipe = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.handleSwipes(_:)))
rightSwipe.direction = .right
leftSwipe.direction = .left
view.addGestureRecognizer(rightSwipe)
view.addGestureRecognizer(leftSwipe)
self.view.backgroundColor = UIColor.black
}
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
print("Message from beyond: \(message.body)")
}
// Make the status bar text light
override var preferredStatusBarStyle : UIStatusBarStyle {
return UIStatusBarStyle.lightContent
}
// Start the toolbar "hidden"
// commenting out these lines should make the toolbar appear, but it doesn't
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
Toolbar.center.x = Toolbar.center.x - self.view.frame.width
}
// Activity Indicator stuff
func webViewDidStartLoad(_ : WKWebView) {
ActInd.startAnimating()
}
func webViewDidFinishLoad(_ : WKWebView) {
ActInd.stopAnimating()
if self.Toolbar.center.x > 0 {
UIView.animate(withDuration: 0.3, animations: { () -> Void in
self.Toolbar.center.x = self.Toolbar.center.x - self.view.frame.width
})
}
}
// handle swipes
func handleSwipes(_ sender:UISwipeGestureRecognizer) {
if (sender.direction == .right) {
if self.Toolbar.center.x < 0 {
UIView.animate(withDuration: 0.3, animations: { () -> Void in
self.Toolbar.center.x = self.Toolbar.center.x + self.view.frame.width
})
}
}
if (sender.direction == .left) {
if self.Toolbar.center.x > 0 {
UIView.animate(withDuration: 0.3, animations: { () -> Void in
self.Toolbar.center.x = self.Toolbar.center.x - self.view.frame.width
})
}
}
}
}