Managed iOS native detachFromEngine flutter plugin event and updated dispose methods, Updated Android native HeadlessInAppWebViewManager.dispose and HeadlessInAppWebView.dispose methods

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 5.4.1
+
+- Managed iOS native `detachFromEngine` flutter plugin event and updated `dispose` methods
+- Updated Android native `HeadlessInAppWebViewManager.dispose` and `HeadlessInAppWebView.dispose` methods
+
 ## 5.4.0+3
 
 - Fixed Android error in some cases when calling `setServiceWorkerClient` java method on `ServiceWorkerManager` initialization

android/src/main/java/com/pichillilorenzo/flutter_inappwebview/headless_in_app_webview/HeadlessInAppWebView.java

@@ -110,12 +110,16 @@ public class HeadlessInAppWebView implements MethodChannel.MethodCallHandler {
   public void dispose() {
     channel.setMethodCallHandler(null);
     HeadlessInAppWebViewManager.webViews.remove(id);
-    ViewGroup contentView = (ViewGroup) plugin.activity.findViewById(android.R.id.content);
+    if (plugin != null) {
-    ViewGroup mainView = (ViewGroup) (contentView).getChildAt(0);
+      ViewGroup contentView = (ViewGroup) plugin.activity.findViewById(android.R.id.content);
-    if (mainView != null) {
+      ViewGroup mainView = (ViewGroup) (contentView).getChildAt(0);
-      mainView.removeView(flutterWebView.getView());
+      if (mainView != null && flutterWebView != null) {
+        mainView.removeView(flutterWebView.getView());
+      }
+    }
+    if (flutterWebView != null) {
+      flutterWebView.dispose();
     }
-    flutterWebView.dispose();
     flutterWebView = null;
     plugin = null;
   }

android/src/main/java/com/pichillilorenzo/flutter_inappwebview/headless_in_app_webview/HeadlessInAppWebViewManager.java

@@ -26,7 +26,9 @@ import androidx.annotation.Nullable;
 import com.pichillilorenzo.flutter_inappwebview.InAppWebViewFlutterPlugin;
 import com.pichillilorenzo.flutter_inappwebview.in_app_webview.FlutterWebView;
 
+import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import io.flutter.plugin.common.MethodCall;
@@ -77,6 +79,10 @@ public class HeadlessInAppWebViewManager implements MethodChannel.MethodCallHand
 
   public void dispose() {
     channel.setMethodCallHandler(null);
+    Collection<HeadlessInAppWebView> headlessInAppWebViews = webViews.values();
+    for (HeadlessInAppWebView headlessInAppWebView : headlessInAppWebViews) {
+      headlessInAppWebView.dispose();
+    }
     webViews.clear();
   }
 }

ios/Classes/CredentialDatabase.swift

@@ -31,7 +31,11 @@ class CredentialDatabase: NSObject, FlutterPlugin {
         switch call.method {
             case "getAllAuthCredentials":
                 var allCredentials: [[String: Any?]] = []
-                for (protectionSpace, credentials) in CredentialDatabase.credentialStore!.allCredentials {
+                guard let credentialStore = CredentialDatabase.credentialStore else {
+                    result(allCredentials)
+                    return
+                }
+                for (protectionSpace, credentials) in credentialStore.allCredentials {
                     var crendentials: [[String: Any?]] = []
                     for c in credentials {
                         let credential: [String: Any?] = c.value.toMap()
@@ -43,10 +47,17 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                             "credentials": crendentials
                         ]
                         allCredentials.append(dict)
-                    }                }
+                    }
+                }
                 result(allCredentials)
                 break
             case "getHttpAuthCredentials":
+                var crendentials: [[String: Any?]] = []
+                guard let credentialStore = CredentialDatabase.credentialStore else {
+                    result(crendentials)
+                    return
+                }
+            
                 let host = arguments!["host"] as! String
                 let urlProtocol = arguments!["protocol"] as? String
                 let urlPort = arguments!["port"] as? Int ?? 0
@@ -54,9 +65,8 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 if let r = realm, r.isEmpty {
                     realm = nil
                 }
-                var crendentials: [[String: Any?]] = []
 
-                for (protectionSpace, credentials) in CredentialDatabase.credentialStore!.allCredentials {
+                for (protectionSpace, credentials) in credentialStore.allCredentials {
                     if protectionSpace.host == host && protectionSpace.realm == realm &&
                     protectionSpace.protocol == urlProtocol && protectionSpace.port == urlPort {
                         for c in credentials {
@@ -68,6 +78,11 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 result(crendentials)
                 break
             case "setHttpAuthCredential":
+                guard let credentialStore = CredentialDatabase.credentialStore else {
+                    result(false)
+                    return
+                }
+            
                 let host = arguments!["host"] as! String
                 let urlProtocol = arguments!["protocol"] as? String
                 let urlPort = arguments!["port"] as? Int ?? 0
@@ -78,11 +93,17 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 let username = arguments!["username"] as! String
                 let password = arguments!["password"] as! String
                 let credential = URLCredential(user: username, password: password, persistence: .permanent)
-                CredentialDatabase.credentialStore!.set(credential,
+                credentialStore.set(credential,
-                                                        for: URLProtectionSpace(host: host, port: urlPort, protocol: urlProtocol, realm: realm, authenticationMethod: NSURLAuthenticationMethodHTTPBasic))
+                                    for: URLProtectionSpace(host: host, port: urlPort, protocol: urlProtocol,
+                                                            realm: realm, authenticationMethod: NSURLAuthenticationMethodHTTPBasic))
                 result(true)
                 break
             case "removeHttpAuthCredential":
+                guard let credentialStore = CredentialDatabase.credentialStore else {
+                    result(false)
+                    return
+                }
+            
                 let host = arguments!["host"] as! String
                 let urlProtocol = arguments!["protocol"] as? String
                 let urlPort = arguments!["port"] as? Int ?? 0
@@ -96,7 +117,7 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 var credential: URLCredential? = nil;
                 var protectionSpaceCredential: URLProtectionSpace? = nil
                 
-                for (protectionSpace, credentials) in CredentialDatabase.credentialStore!.allCredentials {
+                for (protectionSpace, credentials) in credentialStore.allCredentials {
                     if protectionSpace.host == host && protectionSpace.realm == realm &&
                     protectionSpace.protocol == urlProtocol && protectionSpace.port == urlPort {
                         for c in credentials {
@@ -113,12 +134,17 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 }
                 
                 if let c = credential, let protectionSpace = protectionSpaceCredential {
-                    CredentialDatabase.credentialStore!.remove(c, for: protectionSpace)
+                    credentialStore.remove(c, for: protectionSpace)
                 }
                 
                 result(true)
                 break
             case "removeHttpAuthCredentials":
+                guard let credentialStore = CredentialDatabase.credentialStore else {
+                    result(false)
+                    return
+                }
+            
                 let host = arguments!["host"] as! String
                 let urlProtocol = arguments!["protocol"] as? String
                 let urlPort = arguments!["port"] as? Int ?? 0
@@ -130,7 +156,7 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 var credentialsToRemove: [URLCredential] = [];
                 var protectionSpaceCredential: URLProtectionSpace? = nil
                 
-                for (protectionSpace, credentials) in CredentialDatabase.credentialStore!.allCredentials {
+                for (protectionSpace, credentials) in credentialStore.allCredentials {
                     if protectionSpace.host == host && protectionSpace.realm == realm &&
                     protectionSpace.protocol == urlProtocol && protectionSpace.port == urlPort {
                         protectionSpaceCredential = protectionSpace
@@ -145,16 +171,21 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 
                 if let protectionSpace = protectionSpaceCredential {
                     for credential in credentialsToRemove {
-                        CredentialDatabase.credentialStore!.remove(credential, for: protectionSpace)
+                        credentialStore.remove(credential, for: protectionSpace)
                     }
                 }
                 
                 result(true)
                 break
             case "clearAllAuthCredentials":
-                for (protectionSpace, credentials) in CredentialDatabase.credentialStore!.allCredentials {
+                guard let credentialStore = CredentialDatabase.credentialStore else {
+                    result(false)
+                    return
+                }
+            
+                for (protectionSpace, credentials) in credentialStore.allCredentials {
                     for credential in credentials {
-                        CredentialDatabase.credentialStore!.remove(credential.value, for: protectionSpace)
+                        credentialStore.remove(credential.value, for: protectionSpace)
                     }
                 }
                 result(true)
@@ -164,4 +195,11 @@ class CredentialDatabase: NSObject, FlutterPlugin {
                 break
         }
     }
+    
+    public func dispose() {
+        CredentialDatabase.channel?.setMethodCallHandler(nil)
+        CredentialDatabase.channel = nil
+        CredentialDatabase.registrar = nil
+        CredentialDatabase.credentialStore = nil
+    }
 }

ios/Classes/HeadlessInAppWebView/HeadlessInAppWebViewManager.swift

@@ -57,4 +57,15 @@ public class HeadlessInAppWebViewManager: NSObject, FlutterPlugin {
         headlessInAppWebView.onWebViewCreated()
         flutterWebView.makeInitialLoad(params: params as NSDictionary)
     }
+    
+    public func dispose() {
+        HeadlessInAppWebViewManager.channel?.setMethodCallHandler(nil)
+        HeadlessInAppWebViewManager.channel = nil
+        HeadlessInAppWebViewManager.registrar = nil
+        let headlessWebViews = HeadlessInAppWebViewManager.webViews.values
+        headlessWebViews.forEach { (headlessWebView: HeadlessInAppWebView) in
+            headlessWebView.dispose()
+        }
+        HeadlessInAppWebViewManager.webViews.removeAll()
+    }
 }

ios/Classes/InAppBrowser/InAppBrowserManager.swift

@@ -140,4 +140,10 @@ public class InAppBrowserManager: NSObject, FlutterPlugin {
         }
         result(true)
     }
+    
+    public func dispose() {
+        InAppBrowserManager.channel?.setMethodCallHandler(nil)
+        InAppBrowserManager.channel = nil
+        InAppBrowserManager.registrar = nil
+    }
 }

ios/Classes/InAppBrowser/InAppBrowserWebViewController.swift

@@ -182,6 +182,7 @@ public class InAppBrowserWebViewController: UIViewController, InAppBrowserDelega
     
     deinit {
         print("InAppBrowserWebViewController - dealloc")
+        dispose()
     }
     
     public override func viewDidDisappear(_ animated: Bool) {
@@ -550,7 +551,10 @@ public class InAppBrowserWebViewController: UIViewController, InAppBrowserDelega
     }
     
     public func dispose() {
-        webView.dispose()
+        onExit()
+        channel?.setMethodCallHandler(nil)
+        channel = nil
+        webView?.dispose()
         webView = nil
         view = nil
         if previousStatusBarStyle != -1 {
@@ -563,18 +567,15 @@ public class InAppBrowserWebViewController: UIViewController, InAppBrowserDelega
         backButton.target = nil
         reloadButton.target = nil
         shareButton.target = nil
-        onExit()
-        channel?.setMethodCallHandler(nil)
-        channel = nil
         methodCallDelegate?.webView = nil
         methodCallDelegate = nil
     }
     
     public func onBrowserCreated() {
-        channel!.invokeMethod("onBrowserCreated", arguments: [])
+        channel?.invokeMethod("onBrowserCreated", arguments: [])
     }
     
     public func onExit() {
-        channel!.invokeMethod("onExit", arguments: [])
+        channel?.invokeMethod("onExit", arguments: [])
     }
 }

ios/Classes/InAppWebView/FlutterWebViewController.swift

@@ -164,7 +164,8 @@ public class FlutterWebViewController: NSObject, FlutterPlatformView {
     
     func dispose() {
         channel?.setMethodCallHandler(nil)
-        methodCallDelegate?.webView = nil
+        channel = nil
+        methodCallDelegate?.dispose()
         methodCallDelegate = nil
         webView?.dispose()
         webView = nil

ios/Classes/InAppWebView/InAppWebView.swift

@@ -1673,8 +1673,8 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate, WKNavi
                                 completionHandler(.useCredential, credential)
                                 break
                             case 2:
-                                if InAppWebView.credentialsProposed.count == 0 {
+                                if InAppWebView.credentialsProposed.count == 0, let credentialStore = CredentialDatabase.credentialStore {
-                                    for (protectionSpace, credentials) in CredentialDatabase.credentialStore!.allCredentials {
+                                    for (protectionSpace, credentials) in credentialStore.allCredentials {
                                         if protectionSpace.host == host && protectionSpace.realm == realm &&
                                         protectionSpace.protocol == prot && protectionSpace.port == port {
                                             for credential in credentials {
@@ -2900,6 +2900,12 @@ if(window.\(JAVASCRIPT_BRIDGE_NAME)[\(_callHandlerID)] != null) {
     }
     
     public func dispose() {
+        channel = nil
+        removeObserver(self, forKeyPath: #keyPath(WKWebView.estimatedProgress))
+        removeObserver(self, forKeyPath: #keyPath(WKWebView.url))
+        removeObserver(self, forKeyPath: #keyPath(WKWebView.title))
+        scrollView.removeObserver(self, forKeyPath: #keyPath(UIScrollView.contentOffset))
+        scrollView.removeObserver(self, forKeyPath: #keyPath(UIScrollView.zoomScale))
         resumeTimers()
         stopLoading()
         disposeWebMessageChannels()
@@ -2920,15 +2926,10 @@ if(window.\(JAVASCRIPT_BRIDGE_NAME)[\(_callHandlerID)] != null) {
             InAppWebView.windowWebViews.removeValue(forKey: wId)
         }
         configuration.userContentController.dispose(windowId: windowId)
-        removeObserver(self, forKeyPath: #keyPath(WKWebView.estimatedProgress))
-        removeObserver(self, forKeyPath: #keyPath(WKWebView.url))
-        removeObserver(self, forKeyPath: #keyPath(WKWebView.title))
         NotificationCenter.default.removeObserver(self)
         for imp in customIMPs {
             imp_removeBlock(imp)
         }
-        scrollView.removeObserver(self, forKeyPath: #keyPath(UIScrollView.contentOffset))
-        scrollView.removeObserver(self, forKeyPath: #keyPath(UIScrollView.zoomScale))
         longPressRecognizer.removeTarget(self, action: #selector(longPressGestureDetected))
         longPressRecognizer.delegate = nil
         scrollView.removeGestureRecognizer(longPressRecognizer)
@@ -2945,7 +2946,6 @@ if(window.\(JAVASCRIPT_BRIDGE_NAME)[\(_callHandlerID)] != null) {
         navigationDelegate = nil
         scrollView.delegate = nil
         isPausedTimersCompletionHandler = nil
-        channel = nil
         SharedLastTouchPointTimestamp.removeValue(forKey: self)
         callAsyncJavaScriptBelowIOS14Results.removeAll()
         super.removeFromSuperview()

ios/Classes/InAppWebViewMethodHandler.swift

@@ -553,8 +553,12 @@ public class InAppWebViewMethodHandler: FlutterMethodCallDelegate {
         }
     }
     
-    deinit {
+    public func dispose() {
-        print("InAppWebViewMethodHandler - dealloc")
         webView = nil
     }
+    
+    deinit {
+        print("InAppWebViewMethodHandler - dealloc")
+        dispose()
+    }
 }

ios/Classes/InAppWebViewStatic.swift

@@ -72,4 +72,12 @@ class InAppWebViewStatic: NSObject, FlutterPlugin {
             completionHandler(defaultUserAgent)
         }
     }
+    
+    public func dispose() {
+        InAppWebViewStatic.channel?.setMethodCallHandler(nil)
+        InAppWebViewStatic.channel = nil
+        InAppWebViewStatic.registrar = nil
+        InAppWebViewStatic.webViewForUserAgent = nil
+        InAppWebViewStatic.defaultUserAgent = nil
+    }
 }

ios/Classes/MyCookieManager.swift

@@ -100,6 +100,11 @@ class MyCookieManager: NSObject, FlutterPlugin {
                           isHttpOnly: Bool?,
                           sameSite: String?,
                           result: @escaping FlutterResult) {
+        guard let httpCookieStore = MyCookieManager.httpCookieStore else {
+            result(false)
+            return
+        }
+        
         var properties: [HTTPCookiePropertyKey: Any] = [:]
         properties[.originURL] = url
         properties[.name] = name
@@ -138,7 +143,7 @@ class MyCookieManager: NSObject, FlutterPlugin {
         
         let cookie = HTTPCookie(properties: properties)!
         
-        MyCookieManager.httpCookieStore!.setCookie(cookie, completionHandler: {() in
+        httpCookieStore.setCookie(cookie, completionHandler: {() in
             result(true)
         })
     }
@@ -146,8 +151,13 @@ class MyCookieManager: NSObject, FlutterPlugin {
     public static func getCookies(url: String, result: @escaping FlutterResult) {
         var cookieList: [[String: Any?]] = []
         
+        guard let httpCookieStore = MyCookieManager.httpCookieStore else {
+            result(cookieList)
+            return
+        }
+        
         if let urlHost = URL(string: url)?.host {
-            MyCookieManager.httpCookieStore!.getAllCookies { (cookies) in
+            httpCookieStore.getAllCookies { (cookies) in
                 for cookie in cookies {
                     if urlHost.hasSuffix(cookie.domain) || ".\(urlHost)".hasSuffix(cookie.domain) {
                         var sameSite: String? = nil
@@ -189,7 +199,12 @@ class MyCookieManager: NSObject, FlutterPlugin {
     public static func getAllCookies(result: @escaping FlutterResult) {
         var cookieList: [[String: Any?]] = []
         
-        MyCookieManager.httpCookieStore!.getAllCookies { (cookies) in
+        guard let httpCookieStore = MyCookieManager.httpCookieStore else {
+            result(cookieList)
+            return
+        }
+        
+        httpCookieStore.getAllCookies { (cookies) in
             for cookie in cookies {
                 var sameSite: String? = nil
                 if #available(iOS 13.0, *) {
@@ -221,7 +236,12 @@ class MyCookieManager: NSObject, FlutterPlugin {
     }
     
     public static func deleteCookie(url: String, name: String, domain: String, path: String, result: @escaping FlutterResult) {
-        MyCookieManager.httpCookieStore!.getAllCookies { (cookies) in
+        guard let httpCookieStore = MyCookieManager.httpCookieStore else {
+            result(false)
+            return
+        }
+    
+        httpCookieStore.getAllCookies { (cookies) in
             for cookie in cookies {
                 var originURL = ""
                 if cookie.properties![.originURL] is String {
@@ -234,7 +254,7 @@ class MyCookieManager: NSObject, FlutterPlugin {
                     continue
                 }
                 if (cookie.domain == domain || cookie.domain == ".\(domain)" || ".\(cookie.domain)" == domain) && cookie.name == name && cookie.path == path {
-                    MyCookieManager.httpCookieStore!.delete(cookie, completionHandler: {
+                    httpCookieStore.delete(cookie, completionHandler: {
                         result(true)
                     })
                     return
@@ -245,7 +265,12 @@ class MyCookieManager: NSObject, FlutterPlugin {
     }
     
     public static func deleteCookies(url: String, domain: String, path: String, result: @escaping FlutterResult) {
-        MyCookieManager.httpCookieStore!.getAllCookies { (cookies) in
+        guard let httpCookieStore = MyCookieManager.httpCookieStore else {
+            result(false)
+            return
+        }
+        
+        httpCookieStore.getAllCookies { (cookies) in
             for cookie in cookies {
                 var originURL = ""
                 if cookie.properties![.originURL] is String {
@@ -258,7 +283,7 @@ class MyCookieManager: NSObject, FlutterPlugin {
                     continue
                 }
                 if (cookie.domain == domain || cookie.domain == ".\(domain)" || ".\(cookie.domain)" == domain) && cookie.path == path {
-                    MyCookieManager.httpCookieStore!.delete(cookie, completionHandler: nil)
+                    httpCookieStore.delete(cookie, completionHandler: nil)
                 }
             }
             result(true)
@@ -272,4 +297,11 @@ class MyCookieManager: NSObject, FlutterPlugin {
             result(true)
         })
     }
+    
+    public func dispose() {
+        MyCookieManager.channel?.setMethodCallHandler(nil)
+        MyCookieManager.channel = nil
+        MyCookieManager.registrar = nil
+        MyCookieManager.httpCookieStore = nil
+    }
 }

ios/Classes/MyWebStorageManager.swift

@@ -53,7 +53,13 @@ class MyWebStorageManager: NSObject, FlutterPlugin {
     
     public static func fetchDataRecords(dataTypes: Set<String>, result: @escaping FlutterResult) {
         var recordList: [[String: Any?]] = []
-        MyWebStorageManager.websiteDataStore!.fetchDataRecords(ofTypes: dataTypes) { (data) in
+        
+        guard let websiteDataStore = MyWebStorageManager.websiteDataStore else {
+            result(recordList)
+            return
+        }
+        
+        websiteDataStore.fetchDataRecords(ofTypes: dataTypes) { (data) in
             for record in data {
                 recordList.append([
                     "displayName": record.displayName,
@@ -68,7 +74,13 @@ class MyWebStorageManager: NSObject, FlutterPlugin {
     
     public static func removeDataFor(dataTypes: Set<String>, recordList: [[String: Any?]], result: @escaping FlutterResult) {
         var records: [WKWebsiteDataRecord] = []
-        MyWebStorageManager.websiteDataStore!.fetchDataRecords(ofTypes: dataTypes) { (data) in
+        
+        guard let websiteDataStore = MyWebStorageManager.websiteDataStore else {
+            result(false)
+            return
+        }
+        
+        websiteDataStore.fetchDataRecords(ofTypes: dataTypes) { (data) in
             for record in data {
                 for r in recordList {
                     let displayName = r["displayName"] as! String
@@ -78,16 +90,28 @@ class MyWebStorageManager: NSObject, FlutterPlugin {
                     }
                 }
             }
-            MyWebStorageManager.websiteDataStore!.removeData(ofTypes: dataTypes, for: records) {
+            websiteDataStore.removeData(ofTypes: dataTypes, for: records) {
                 result(true)
             }
         }
     }
     
     public static func removeDataModifiedSince(dataTypes: Set<String>, timestamp: Int64, result: @escaping FlutterResult) {
+        guard let websiteDataStore = MyWebStorageManager.websiteDataStore else {
+            result(false)
+            return
+        }
+        
         let date = NSDate(timeIntervalSince1970: TimeInterval(timestamp))
-        MyWebStorageManager.websiteDataStore!.removeData(ofTypes: dataTypes, modifiedSince: date as Date) {
+        websiteDataStore.removeData(ofTypes: dataTypes, modifiedSince: date as Date) {
             result(true)
         }
     }
+    
+    public func dispose() {
+        MyWebStorageManager.channel?.setMethodCallHandler(nil)
+        MyWebStorageManager.channel = nil
+        MyWebStorageManager.registrar = nil
+        MyWebStorageManager.websiteDataStore = nil
+    }
 }

ios/Classes/PlatformUtil.swift

@@ -60,4 +60,10 @@ class PlatformUtil: NSObject, FlutterPlugin {
         formatter.timeZone = timezone
         return formatter.string(from: PlatformUtil.getDateFromMilliseconds(date: date))
     }
+    
+    public func dispose() {
+        PlatformUtil.channel?.setMethodCallHandler(nil)
+        PlatformUtil.channel = nil
+        PlatformUtil.registrar = nil
+    }
 }

ios/Classes/PullToRefresh/PullToRefreshControl.swift

@@ -109,5 +109,6 @@ public class PullToRefreshControl : UIRefreshControl, FlutterPlugin {
     
     deinit {
         print("PullToRefreshControl - dealloc")
+        dispose()
     }
 }

ios/Classes/SafariViewController/ChromeSafariBrowserManager.swift

@@ -91,4 +91,10 @@ public class ChromeSafariBrowserManager: NSObject, FlutterPlugin {
         
         result(FlutterError.init(code: "ChromeSafariBrowserManager", message: "SafariViewController is not available!", details: nil))
     }
+    
+    public func dispose() {
+        ChromeSafariBrowserManager.channel?.setMethodCallHandler(nil)
+        ChromeSafariBrowserManager.channel = nil
+        ChromeSafariBrowserManager.registrar = nil
+    }
 }

ios/Classes/SafariViewController/SafariViewController.swift

@@ -22,6 +22,7 @@ public class SafariViewController: SFSafariViewController, FlutterPlugin, SFSafa
     
     deinit {
         print("SafariViewController - dealloc")
+        dispose()
     }
     
     public func prepareMethodChannel() {
@@ -123,20 +124,21 @@ public class SafariViewController: SFSafariViewController, FlutterPlugin, SFSafa
 //    }
     
     public func onChromeSafariBrowserOpened() {
-        channel!.invokeMethod("onChromeSafariBrowserOpened", arguments: [])
+        channel?.invokeMethod("onChromeSafariBrowserOpened", arguments: [])
     }
     
     public func onChromeSafariBrowserCompletedInitialLoad() {
-        channel!.invokeMethod("onChromeSafariBrowserCompletedInitialLoad", arguments: [])
+        channel?.invokeMethod("onChromeSafariBrowserCompletedInitialLoad", arguments: [])
     }
     
     public func onChromeSafariBrowserClosed() {
-        channel!.invokeMethod("onChromeSafariBrowserClosed", arguments: [])
+        channel?.invokeMethod("onChromeSafariBrowserClosed", arguments: [])
     }
     
     public func dispose() {
+        channel?.setMethodCallHandler(nil)
+        channel = nil
         delegate = nil
-        channel!.setMethodCallHandler(nil)
     }
 }
 
@@ -180,7 +182,12 @@ class CustomUIActivity : UIActivity {
     }
 
     override func perform() {
-        let channel = FlutterMethodChannel(name: "com.pichillilorenzo/flutter_chromesafaribrowser_" + viewId, binaryMessenger: SwiftFlutterPlugin.instance!.registrar!.messenger())
+        guard let registrar = SwiftFlutterPlugin.instance?.registrar else {
+            return
+        }
+        
+        let channel = FlutterMethodChannel(name: "com.pichillilorenzo/flutter_chromesafaribrowser_" + viewId,
+                                           binaryMessenger: registrar.messenger())
         
         let arguments: [String: Any?] = [
             "url": url.absoluteString,

ios/Classes/SwiftFlutterPlugin.swift

@@ -49,16 +49,39 @@ public class SwiftFlutterPlugin: NSObject, FlutterPlugin {
         headlessInAppWebViewManager = HeadlessInAppWebViewManager(registrar: registrar)
         chromeSafariBrowserManager = ChromeSafariBrowserManager(registrar: registrar)
         inAppWebViewStatic = InAppWebViewStatic(registrar: registrar)
+        credentialDatabase = CredentialDatabase(registrar: registrar)
         if #available(iOS 11.0, *) {
             myCookieManager = MyCookieManager(registrar: registrar)
         }
         if #available(iOS 9.0, *) {
             myWebStorageManager = MyWebStorageManager(registrar: registrar)
         }
-        credentialDatabase = CredentialDatabase(registrar: registrar)
     }
     
     public static func register(with registrar: FlutterPluginRegistrar) {
         SwiftFlutterPlugin.instance = SwiftFlutterPlugin(with: registrar)
     }
+    
+    public func detachFromEngine(for registrar: FlutterPluginRegistrar) {
+        platformUtil?.dispose()
+        platformUtil = nil
+        inAppBrowserManager?.dispose()
+        inAppBrowserManager = nil
+        headlessInAppWebViewManager?.dispose()
+        headlessInAppWebViewManager = nil
+        chromeSafariBrowserManager?.dispose()
+        chromeSafariBrowserManager = nil
+        inAppWebViewStatic?.dispose()
+        inAppWebViewStatic = nil
+        credentialDatabase?.dispose()
+        credentialDatabase = nil
+        if #available(iOS 11.0, *) {
+            (myCookieManager as! MyCookieManager?)?.dispose()
+            myCookieManager = nil
+        }
+        if #available(iOS 9.0, *) {
+            (myWebStorageManager as! MyWebStorageManager?)?.dispose()
+            myWebStorageManager = nil
+        }
+    }
 }

ios/Classes/Types/WKUserContentController.swift

@@ -21,7 +21,7 @@ extension WKUserContentController {
     var contentWorlds: Set<WKContentWorld> {
         get {
             let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))
-            return WKUserContentController._contentWorlds[tmpAddress]!
+            return WKUserContentController._contentWorlds[tmpAddress] ?? []
         }
         set(newValue) {
             let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))
@@ -33,7 +33,7 @@ extension WKUserContentController {
     var userOnlyScripts: [WKUserScriptInjectionTime:OrderedSet<UserScript>] {
         get {
             let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))
-            return WKUserContentController._userOnlyScripts[tmpAddress]!
+            return WKUserContentController._userOnlyScripts[tmpAddress] ?? [:]
         }
         set(newValue) {
             let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))
@@ -45,7 +45,7 @@ extension WKUserContentController {
     var pluginScripts: [WKUserScriptInjectionTime:OrderedSet<PluginScript>] {
         get {
             let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))
-            return WKUserContentController._pluginScripts[tmpAddress]!
+            return WKUserContentController._pluginScripts[tmpAddress] ?? [:]
         }
         set(newValue) {
             let tmpAddress = String(format: "%p", unsafeBitCast(self, to: Int.self))

ios/Classes/Types/WebMessage.swift

@@ -23,5 +23,6 @@ public class WebMessage : NSObject {
     
     deinit {
         print("WebMessage - dealloc")
+        dispose()
     }
 }

ios/Classes/Types/WebMessageChannel.swift

@@ -126,6 +126,7 @@ public class WebMessageChannel : FlutterMethodCallDelegate {
     
     public func dispose() {
         channel?.setMethodCallHandler(nil)
+        channel = nil
         for port in ports {
             port.dispose()
         }
@@ -140,11 +141,11 @@ public class WebMessageChannel : FlutterMethodCallDelegate {
             }
         })();
         """)
-        channel = nil
         webView = nil
     }
     
     deinit {
         print("WebMessageChannel - dealloc")
+        dispose()
     }
 }

ios/Classes/Types/WebMessageListener.swift

@@ -222,5 +222,6 @@ public class WebMessageListener : FlutterMethodCallDelegate {
     
     deinit {
         print("WebMessageListener - dealloc")
+        dispose()
     }
 }

ios/Classes/Types/WebMessagePort.swift

@@ -118,5 +118,6 @@ public class WebMessagePort : NSObject {
     
     deinit {
         print("WebMessagePort - dealloc")
+        dispose()
     }
 }

ios/Classes/Util.swift

@@ -12,7 +12,7 @@ var SharedLastTouchPointTimestamp: [InAppWebView: Int64] = [:]
 
 public class Util {
     public static func getUrlAsset(assetFilePath: String) throws -> URL {
-        let key = SwiftFlutterPlugin.instance!.registrar!.lookupKey(forAsset: assetFilePath)
+        let key = SwiftFlutterPlugin.instance?.registrar?.lookupKey(forAsset: assetFilePath)
         guard let assetURL = Bundle.main.url(forResource: key, withExtension: nil) else {
             throw NSError(domain: assetFilePath + " asset file cannot be found!", code: 0)
         }
@@ -20,7 +20,7 @@ public class Util {
     }
     
     public static func getAbsPathAsset(assetFilePath: String) throws -> String {
-        let key = SwiftFlutterPlugin.instance!.registrar!.lookupKey(forAsset: assetFilePath)
+        let key = SwiftFlutterPlugin.instance?.registrar?.lookupKey(forAsset: assetFilePath)
         guard let assetAbsPath = Bundle.main.path(forResource: key, ofType: nil) else {
             throw NSError(domain: assetFilePath + " asset file cannot be found!", code: 0)
         }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_inappwebview
 description: A Flutter plugin that allows you to add an inline webview, to use an headless webview, and to open an in-app browser window.
-version: 5.4.0+3
+version: 5.4.1
 homepage: https://github.com/pichillilorenzo/flutter_inappwebview
 
 environment: