iOS 13 SceneDelegateでWKWebView Alertがクラッシュする
***キャッチされない例外 'NSObjectNotAvailableException'によりアプリを終了しています、理由： 'UIAlertViewは非推奨であり、UISceneベースのアプリケーションでは使用できません。UIAlertControllerを使用してください！'
WKWebViewからのアラートで、上記のエラーがスローされます。
UIAlertViewは、WebページのJavaScriptから呼び出されます。 UIAlertViewを手動で呼び出していません。
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))
}
}
「現在地」をクリックして地図を読み込んだ後、アプリがクラッシュします。
シミュレータ（バージョン13.2.2）でエラーを再現できました。クイック検索を行ったところ、位置情報の許可を処理するための代替ソースを提供し、WKWebViewに位置情報の更新を提供できることがわかりました。以下は、仕事を成し遂げることができるコードです。
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;
}
}
NavigatorGeolocationコードはこれから取得されます Answer 投稿者 mikep
（ヒント：コメントも読んでください）
出力（シミュレータ->デバッグ->場所->アップル）： 
私はこれを（自分でこのバグに遭遇した後）iOS 13.4ベータ版で試しましたが、解決されたようです。
それはあなたに答えを与えます：
キャッチされない例外「NSObjectNotAvailableException」によるアプリの終了、理由：「UIAlertViewは非推奨であり、UISceneベースのアプリケーションでは使用できませんIAlertControllerを使用してください！」
UIAlertControllerを使用する必要があります
let alert = UIAlertController(title: "My Alert",
message: "This is an alert.",
preferredStyle: .alert)
alert.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Default action"), style: .default, handler: { _ in
print("The \"OK\" alert occured.")
}))
self.present(alert, animated: true, completion: nil)