iosswiftuialertviewios13uialertcontroller
WKWebView Alert crash on iOS 13 SceneDelegate
*** Terminating app due to uncaught exception 'NSObjectNotAvailableException', reason: 'UIAlertView is deprecated and unavailable for UIScene based applications, please use UIAlertController!'
On alert from WKWebView it throws above error.
UIAlertView is called from Javascript in Webpage. I'm not calling UIAlertView manually.
import UIKit
import WebKit
class ViewController: UIViewController{
@IBOutlet weak var webView: WKWebView!
override func viewDidLoad() {
super.viewDidLoad()
let url = URL(string: "https://www.google.com/maps")!
webView.load(URLRequest(url: url))
}
}
After maps are loaded when I click on "Your Location", app crashes.
Solution
I was able to reproduce the Error on the Simulator(version 13.2.2). I did a quick search and found that we can provide an alternate source for handling location permission and provide location updates to WKWebView. Below is the code that can get the job done.
ViewController.swift
import UIKit
import WebKit
class ViewController: UIViewController {
var navigatorGeolocation = NavigatorGeolocation();
var web: WKWebView!
override func viewDidLoad() {
super.viewDidLoad()
let webViewConfiguration = WKWebViewConfiguration();
navigatorGeolocation.setUserContentController(webViewConfiguration: webViewConfiguration);
web = WKWebView(frame:.zero , configuration: webViewConfiguration)
web.navigationDelegate = self;
navigatorGeolocation.setWebView(webView: web);
view.addSubview(web);
web.translatesAutoresizingMaskIntoConstraints = false
let constraints = [
web.topAnchor.constraint(equalTo: view.topAnchor),
web.leadingAnchor.constraint(equalTo: view.leadingAnchor),
web.bottomAnchor.constraint(equalTo: view.bottomAnchor),
web.trailingAnchor.constraint(equalTo: view.trailingAnchor)
]
NSLayoutConstraint.activate(constraints)
let url = URL(string: "https://www.google.com/maps")!
web.load(URLRequest(url: url))
}
}
extension ViewController: WKNavigationDelegate{
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
webView.evaluateJavaScript(navigatorGeolocation.getJavaScripToEvaluate());
}
}
NavigatorGeolocation.swift
import WebKit
import CoreLocation
class NavigatorGeolocation: NSObject, WKScriptMessageHandler, CLLocationManagerDelegate {
var locationManager = CLLocationManager();
var listenersCount = 0;
var webView: WKWebView!;
var controller: WKUserContentController?
override init() {
super.init();
locationManager.delegate = self;
}
func setUserContentController(webViewConfiguration: WKWebViewConfiguration) {
controller = WKUserContentController();
controller?.add(self, name: "listenerAdded")
controller?.add(self, name: "listenerRemoved")
webViewConfiguration.userContentController = controller!
}
func setWebView(webView: WKWebView) {
self.webView = webView;
}
func locationServicesIsEnabled() -> Bool {
return (CLLocationManager.locationServicesEnabled()) ? true : false;
}
func authorizationStatusNeedRequest(status: CLAuthorizationStatus) -> Bool {
return (status == .notDetermined) ? true : false;
}
func authorizationStatusIsGranted(status: CLAuthorizationStatus) -> Bool {
return (status == .authorizedAlways || status == .authorizedWhenInUse) ? true : false;
}
func authorizationStatusIsDenied(status: CLAuthorizationStatus) -> Bool {
return (status == .restricted || status == .denied) ? true : false;
}
func onLocationServicesIsDisabled() {
webView.evaluateJavaScript("navigator.geolocation.helper.error(2, 'Location services disabled');");
}
func onAuthorizationStatusNeedRequest() {
locationManager.requestWhenInUseAuthorization();
}
func onAuthorizationStatusIsGranted() {
locationManager.startUpdatingLocation();
}
func onAuthorizationStatusIsDenied() {
webView.evaluateJavaScript("navigator.geolocation.helper.error(1, 'App does not have location permission');");
}
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
if (message.name == "listenerAdded") {
listenersCount += 1;
if (!locationServicesIsEnabled()) {
onLocationServicesIsDisabled();
}
else if (authorizationStatusIsDenied(status: CLLocationManager.authorizationStatus())) {
onAuthorizationStatusIsDenied();
}
else if (authorizationStatusNeedRequest(status: CLLocationManager.authorizationStatus())) {
onAuthorizationStatusNeedRequest();
}
else if (authorizationStatusIsGranted(status: CLLocationManager.authorizationStatus())) {
onAuthorizationStatusIsGranted();
}
}
else if (message.name == "listenerRemoved") {
listenersCount -= 1;
// no listener left in web view to wait for position
if (listenersCount == 0) {
locationManager.stopUpdatingLocation();
}
}
}
func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
// didChangeAuthorization is also called at app startup, so this condition checks listeners
// count before doing anything otherwise app will start location service without reason
if (listenersCount > 0) {
if (authorizationStatusIsDenied(status: status)) {
onAuthorizationStatusIsDenied();
}
else if (authorizationStatusIsGranted(status: status)) {
onAuthorizationStatusIsGranted();
}
}
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if let location = locations.last {
webView.evaluateJavaScript("navigator.geolocation.helper.success('\(location.timestamp)', \(location.coordinate.latitude), \(location.coordinate.longitude), \(location.altitude), \(location.horizontalAccuracy), \(location.verticalAccuracy), \(location.course), \(location.speed));");
}
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
webView.evaluateJavaScript("navigator.geolocation.helper.error(2, 'Failed to get position (\(error.localizedDescription))');");
}
func getJavaScripToEvaluate() -> String {
let javaScripToEvaluate = """
// management for success and error listeners and its calling
navigator.geolocation.helper = {
listeners: {},
noop: function() {},
id: function() {
var min = 1, max = 1000;
return Math.floor(Math.random() * (max - min + 1)) + min;
},
clear: function(isError) {
for (var id in this.listeners) {
if (isError || this.listeners[id].onetime) {
navigator.geolocation.clearWatch(id);
}
}
},
success: function(timestamp, latitude, longitude, altitude, accuracy, altitudeAccuracy, heading, speed) {
var position = {
timestamp: new Date(timestamp).getTime() || new Date().getTime(), // safari can not parse date format returned by swift e.g. 2019-12-27 15:46:59 +0000 (fallback used because we trust that safari will learn it in future because chrome knows that format)
coords: {
latitude: latitude,
longitude: longitude,
altitude: altitude,
accuracy: accuracy,
altitudeAccuracy: altitudeAccuracy,
heading: (heading > 0) ? heading : null,
speed: (speed > 0) ? speed : null
}
};
for (var id in this.listeners) {
this.listeners[id].success(position);
}
this.clear(false);
},
error: function(code, message) {
var error = {
PERMISSION_DENIED: 1,
POSITION_UNAVAILABLE: 2,
TIMEOUT: 3,
code: code,
message: message
};
for (var id in this.listeners) {
this.listeners[id].error(error);
}
this.clear(true);
}
};
// @override getCurrentPosition()
navigator.geolocation.getCurrentPosition = function(success, error, options) {
var id = this.helper.id();
this.helper.listeners[id] = { onetime: true, success: success || this.noop, error: error || this.noop };
window.webkit.messageHandlers.listenerAdded.postMessage("");
};
// @override watchPosition()
navigator.geolocation.watchPosition = function(success, error, options) {
var id = this.helper.id();
this.helper.listeners[id] = { onetime: false, success: success || this.noop, error: error || this.noop };
window.webkit.messageHandlers.listenerAdded.postMessage("");
return id;
};
// @override clearWatch()
navigator.geolocation.clearWatch = function(id) {
var idExists = (this.helper.listeners[id]) ? true : false;
if (idExists) {
this.helper.listeners[id] = null;
delete this.helper.listeners[id];
window.webkit.messageHandlers.listenerRemoved.postMessage("");
}
};
""";
return javaScripToEvaluate;
}
}
The NavigatorGeolocation code is taken from this Answer posted by mikep
(Tip: Read the comments also)
Output(Simulator->Debug->Location->Apple):
