Try to avoid crash by apply Telerik-Verified-Plugins/WKWebView#248 (c…

…omment)
ainopara · Jan 7, 2017 · 8d622a9 · 8d622a9
1 parent b6a55f0
commit 8d622a9
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Showing 3 changed files with 56 additions and 44 deletions.
diff --git a/Stage1st/ContentViewController.swift b/Stage1st/ContentViewController.swift
@@ -300,8 +300,6 @@ class S1ContentViewController: UIViewController, ImagePresenter, UserPresenter,
         NotificationCenter.default.removeObserver(self)
         webView.configuration.userContentController.removeScriptMessageHandler(forName: "stage1st")
         pullToActionController.stop()
-        webView.navigationDelegate = nil
-        webView.stopLoading()
         DDLogInfo("[ContentVC] Dealloced")
     }
 }
@@ -366,7 +364,6 @@ extension S1ContentViewController {
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
 
-        let previousPresentType = presentType
         presentType = .none
 
         // defer from initializer to here to make sure navigationController exist (i.e. self be added to navigation stack)
@@ -378,11 +375,7 @@ extension S1ContentViewController {
         didReceivePaletteChangeNotification(nil)
 
         // Also use this method to initialize content.
-        if case .image = previousPresentType {
-            // Note: Calling evaluateJavaScript to WKWebView will cause the content of it changed to blank before completionHandler return. That will lead to screen blink when user coming back from image viewer.
-        } else {
-            _tryToReloadWKWebViewIfPageIsBlankDueToMemoryWarning()
-        }
+        _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated()
     }
 
     override func viewDidDisappear(_ animated: Bool) {
@@ -399,7 +392,7 @@ extension S1ContentViewController {
 
     func applicationWillEnterForeground() {
         DDLogDebug("[ContentVC] \(self) will enter foreground begin")
-        _tryToReloadWKWebViewIfPageIsBlankDueToMemoryWarning()
+        _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated()
     }
 
     func applicationDidEnterBackground() {
@@ -761,7 +754,7 @@ extension S1ContentViewController: WKNavigationDelegate {
     }
 
     func webViewWebContentProcessDidTerminate(_ webView: WKWebView) {
-        DDLogInfo("[ContentVC] webViewWebContentProcessDidTerminate")
+        DDLogError("[ContentVC] webViewWebContentProcessDidTerminate")
     }
 
     func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
@@ -1287,14 +1280,10 @@ extension S1ContentViewController {
         bottomDecorateLine.isHidden = !self.finishFirstLoading.value
     }
 
-    func _tryToReloadWKWebViewIfPageIsBlankDueToMemoryWarning() {
-        // http://stackoverflow.com/questions/27809259/detecting-whether-a-wkwebview-has-blanked
-        webView.evaluateJavaScript("document.querySelector('body').innerHTML") { [weak self] (result, error) in
-            guard let strongSelf = self else { return }
-            guard let result = result as? String, result != "" else {
-                strongSelf.refreshCurrentPage(forceUpdate: !strongSelf.finishFirstLoading.value && strongSelf.viewModel.isInLastPage(), scrollType: .restorePosition)
-                return
-            }
+    func _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated() {
+        guard let title = webView.title, title != "" else {
+            refreshCurrentPage(forceUpdate: !finishFirstLoading.value && viewModel.isInLastPage(), scrollType: .restorePosition)
+            return
         }
     }
 

diff --git a/Stage1st/S1QuoteFloorViewController.swift b/Stage1st/S1QuoteFloorViewController.swift
@@ -47,6 +47,10 @@ class S1QuoteFloorViewController: UIViewController, ImagePresenter, UserPresente
         webView.scrollView.delegate = self
         webView.isOpaque = false
 
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(applicationWillEnterForeground),
+                                               name: .UIApplicationWillEnterForeground,
+                                               object: nil)
         NotificationCenter.default.addObserver(self,
                                                selector: #selector(didReceivePaletteChangeNotification(_:)),
                                                name: .APPaletteDidChangeNotification,
@@ -61,7 +65,6 @@ class S1QuoteFloorViewController: UIViewController, ImagePresenter, UserPresente
         DDLogInfo("[QuoteFloorVC] Dealloc Begin")
         NotificationCenter.default.removeObserver(self)
         webView.configuration.userContentController.removeScriptMessageHandler(forName: "stage1st")
-        webView.navigationDelegate = nil
         webView.stopLoading()
         DDLogInfo("[QuoteFloorVC] Dealloced")
     }
@@ -81,7 +84,6 @@ class S1QuoteFloorViewController: UIViewController, ImagePresenter, UserPresente
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
 
-        let previousPresentType = presentType
         presentType = .none
 
         // defer from initializer to here to make sure navigationController exist (i.e. self be added to navigation stack)
@@ -92,19 +94,13 @@ class S1QuoteFloorViewController: UIViewController, ImagePresenter, UserPresente
 
         didReceivePaletteChangeNotification(nil)
 
-        // http://stackoverflow.com/questions/27809259/detecting-whether-a-wkwebview-has-blanked
-        // Also use this method to initialize content.
-        if case .image = previousPresentType {
-            /// Note: Calling evaluateJavaScript to WKWebView will cause the content of it changed to blank before completionHandler return. That will lead to screen blink when user coming back from image viewer.
-        } else {
-            webView.evaluateJavaScript("document.querySelector('body').innerHTML") { [weak self] (result, error) in
-                guard let strongSelf = self else { return }
-                guard let result = result as? String, result != "" else {
-                    strongSelf.webView.loadHTMLString(strongSelf.viewModel.generatePage(with: strongSelf.viewModel.floors), baseURL: strongSelf.viewModel.baseURL)
-                    return
-                }
-            }
-        }
+        _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated()
+    }
+
+    func applicationWillEnterForeground() {
+        DDLogDebug("[QuoteFloorVC] \(self) will enter foreground begin")
+        _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated()
+        DDLogDebug("[QuoteFloorVC] \(self) will enter foreground end")
     }
 }
 
@@ -241,6 +237,10 @@ extension S1QuoteFloorViewController: WKNavigationDelegate {
         return
     }
 
+    func webViewWebContentProcessDidTerminate(_ webView: WKWebView) {
+        DDLogError("[QuoteFloor] \(#function)")
+    }
+
     func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
         DispatchQueue.global().async { [weak self] in
             guard let strongSelf = self else { return }
@@ -270,6 +270,13 @@ extension S1QuoteFloorViewController {
             return 0.0
         }
     }
+
+    func _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated() {
+        guard let title = webView.title, title != "" else {
+            webView.loadHTMLString(viewModel.generatePage(with: viewModel.floors), baseURL: viewModel.baseURL)
+            return
+        }
+    }
 }
 
 // MARK: - Style

diff --git a/Vendors/S1WebViewController/WebViewController.swift b/Vendors/S1WebViewController/WebViewController.swift
@@ -62,7 +62,14 @@ class WebViewController: UIViewController, WKNavigationDelegate {
 
         updateBarItems()
 
-        NotificationCenter.default.addObserver(self, selector: #selector(didReceivePaletteChangeNotification(_:)), name: .APPaletteDidChangeNotification, object: nil)
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(applicationWillEnterForeground),
+                                               name: .UIApplicationWillEnterForeground,
+                                               object: nil)
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(didReceivePaletteChangeNotification(_:)),
+                                               name: .APPaletteDidChangeNotification,
+                                               object: nil)
     }
 
     required init?(coder aDecoder: NSCoder) {
@@ -133,16 +140,14 @@ class WebViewController: UIViewController, WKNavigationDelegate {
     override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
         self.didReceivePaletteChangeNotification(nil)
+        DDLogInfo("[WebVC] view will appear")
 
-        // http://stackoverflow.com/questions/27809259/detecting-whether-a-wkwebview-has-blanked
-        // Also use this method to initialize content.
-        webView.evaluateJavaScript("document.querySelector('body').innerHTML") { [weak self] (result, error) in
-            guard let strongSelf = self else { return }
-            guard let result = result as? String, result != "" else {
-                strongSelf.webView.load(URLRequest(url: strongSelf.currentValidURL()))
-                return
-            }
-        }
+        _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated()
+    }
+
+    func applicationWillEnterForeground() {
+        DDLogDebug("[WebVC] \(self) will enter foreground begin")
+        _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated()
     }
 
     // MARK: Layout
@@ -184,7 +189,7 @@ class WebViewController: UIViewController, WKNavigationDelegate {
         }
     }
 
-    // MARK: - UIWebViewDelegate
+    // MARK: - WKWebViewNavigationDelegate
     func webView(_ webView: WKWebView, didCommit navigation: WKNavigation!) {
         DDLogDebug("[WebVC] didCommit")
         updateBarItems()
@@ -206,6 +211,10 @@ class WebViewController: UIViewController, WKNavigationDelegate {
         updateBarItems()
     }
 
+    func webViewWebContentProcessDidTerminate(_ webView: WKWebView) {
+        DDLogError("[WebVC] \(#function)")
+    }
+
     // MARK: KVO
     override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
         guard let newProgress = change?[NSKeyValueChangeKey.newKey] as? Float else { return }
@@ -248,6 +257,13 @@ class WebViewController: UIViewController, WKNavigationDelegate {
         }
     }
 
+    func _tryToReloadWKWebViewIfPageIsBlankDueToWebKitProcessTerminated() {
+        guard let title = webView.title, title != "" else {
+            webView.load(URLRequest(url: currentValidURL()))
+            return
+        }
+    }
+
     // MARK: - Notification
     override func didReceivePaletteChangeNotification(_ notification: Notification?) {
         statusBarSeparatorView.backgroundColor = APColorManager.shared.colorForKey("default.text.tint")