Introduce onCanGoBackChange & onCanGoForwardChange

WKWebView.ios.js

@@ -173,6 +173,8 @@ class WKWebView extends React.Component {
      * Report the progress
      */
     onProgress: PropTypes.func,
+    onCanGoBackChange: PropTypes.func,
+    onCanGoForwardChange: PropTypes.func,
     /**
      * A function that is invoked when the webview calls `window.postMessage`.
      * Setting this property will inject a `postMessage` global into your
@@ -362,6 +364,8 @@ class WKWebView extends React.Component {
         onLoadingError={this._onLoadingError}
         messagingEnabled={messagingEnabled}
         onProgress={this._onProgress}
+        onCanGoBackChange={this._onCanGoBackChange}
+        onCanGoForwardChange={this._onCanGoForwardChange}
         onMessage={this._onMessage}
         onScroll={this._onScroll}
         onShouldStartLoadWithRequest={onShouldStartLoadWithRequest}
@@ -511,6 +515,16 @@ class WKWebView extends React.Component {
     onProgress && onProgress(event.nativeEvent.progress);
   };
 
+  _onCanGoBackChange = (event: Event) => {
+    const onCanGoBackChange = this.props.onCanGoBackChange;
+    onCanGoBackChange && onCanGoBackChange(event.nativeEvent.canGoBack);
+  }
+
+  _onCanGoForwardChange = (event: Event) => {
+    const onCanGoForwardChange = this.props.onCanGoForwardChange;
+    onCanGoForwardChange && onCanGoForwardChange(event.nativeEvent.canGoForward);
+  }
+
   _onMessage = (event: Event) => {
     var { onMessage } = this.props;
     onMessage && onMessage(event);

ios/RCTWKWebView/CRAWKWebView.m

@@ -34,6 +34,8 @@ @interface CRAWKWebView () <WKNavigationDelegate, RCTAutoInsetsProtocol, WKScrip
 @property (nonatomic, copy) RCTDirectEventBlock onMessage;
 @property (nonatomic, copy) RCTDirectEventBlock onScroll;
 @property (nonatomic, copy) RCTDirectEventBlock onNavigationResponse;
+@property (nonatomic, copy) RCTDirectEventBlock onCanGoBackChange;
+@property (nonatomic, copy) RCTDirectEventBlock onCanGoForwardChange;
 @property (assign) BOOL sendCookies;
 @property (nonatomic, strong) WKUserScript *atStartScript;
 @property (nonatomic, strong) WKUserScript *atEndScript;
@@ -63,18 +65,18 @@ - (instancetype)initWithProcessPool:(WKProcessPool *)processPool
     super.backgroundColor = [UIColor clearColor];
     _automaticallyAdjustContentInsets = YES;
     _contentInset = UIEdgeInsetsZero;
-    
+
     WKWebViewConfiguration* config = [[WKWebViewConfiguration alloc] init];
     config.processPool = processPool;
     WKUserContentController* userController = [[WKUserContentController alloc]init];
     [userController addScriptMessageHandler:[[WeakScriptMessageDelegate alloc] initWithDelegate:self] name:@"reactNative"];
     config.userContentController = userController;
-    
+
     _webView = [[WKWebView alloc] initWithFrame:self.bounds configuration:config];
     _webView.UIDelegate = self;
     _webView.navigationDelegate = self;
     _webView.scrollView.delegate = self;
-    
+
 #if defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && __IPHONE_OS_VERSION_MAX_ALLOWED >= 110000 /* __IPHONE_11_0 */
     // `contentInsetAdjustmentBehavior` is only available since iOS 11.
     // We set the default behavior to "never" so that iOS
@@ -86,6 +88,8 @@ - (instancetype)initWithProcessPool:(WKProcessPool *)processPool
 #endif
     [self setupPostMessageScript];
     [_webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:nil];
+    [_webView addObserver:self forKeyPath:@"canGoBack" options:NSKeyValueObservingOptionNew context:nil];
+    [_webView addObserver:self forKeyPath:@"canGoForward" options:NSKeyValueObservingOptionNew context:nil];
     [self addSubview:_webView];
   }
   return self;
@@ -163,7 +167,7 @@ - (void)loadRequest:(NSURLRequest *)request
       request = mutableRequest;
     }
   }
-  
+
   [_webView loadRequest:request];
 }
 
@@ -179,29 +183,29 @@ -(void)setHideKeyboardAccessoryView:(BOOL)hideKeyboardAccessoryView
   if (!hideKeyboardAccessoryView) {
     return;
   }
-  
+
   UIView* subview;
   for (UIView* view in _webView.scrollView.subviews) {
     if([[view.class description] hasPrefix:@"WKContent"])
       subview = view;
   }
-  
+
   if(subview == nil) return;
-  
+
   NSString* name = [NSString stringWithFormat:@"%@_SwizzleHelperWK", subview.class.superclass];
   Class newClass = NSClassFromString(name);
-  
+
   if(newClass == nil)
   {
     newClass = objc_allocateClassPair(subview.class, [name cStringUsingEncoding:NSASCIIStringEncoding], 0);
     if(!newClass) return;
-    
+
     Method method = class_getInstanceMethod([_SwizzleHelperWK class], @selector(inputAccessoryView));
     class_addMethod(newClass, @selector(inputAccessoryView), method_getImplementation(method), method_getTypeEncoding(method));
-    
+
     objc_registerClassPair(newClass);
   }
-  
+
   object_setClass(subview, newClass);
 }
 
@@ -212,7 +216,7 @@ -(void)setKeyboardDisplayRequiresUserAction:(BOOL)keyboardDisplayRequiresUserAct
   if (!keyboardDisplayRequiresUserAction) {
     Class class = NSClassFromString(@"WKContentView");
     NSOperatingSystemVersion iOS_11_3_0 = (NSOperatingSystemVersion){11, 3, 0};
-    
+
     if ([[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion: iOS_11_3_0]) {
       SEL selector = sel_getUid("_startAssistingNode:userIsInteracting:blurPreviousNode:changingActivityState:userObject:");
       Method method = class_getInstanceMethod(class, selector);
@@ -314,20 +318,20 @@ - (void)setSource:(NSDictionary *)source
     if ([source[@"customUserAgent"] length] != 0 && [_webView respondsToSelector:@selector(setCustomUserAgent:)]) {
       [_webView setCustomUserAgent:source[@"customUserAgent"]];
     }
-    
+
     // Allow loading local files:
     // <WKWebView source={{ file: RNFS.MainBundlePath + '/data/index.html', allowingReadAccessToURL: RNFS.MainBundlePath }} />
     // Only works for iOS 9+. So iOS 8 will simply ignore those two values
     NSString *file = [RCTConvert NSString:source[@"file"]];
     NSString *allowingReadAccessToURL = [RCTConvert NSString:source[@"allowingReadAccessToURL"]];
-    
+
     if (file && [_webView respondsToSelector:@selector(loadFileURL:allowingReadAccessToURL:)]) {
       NSURL *fileURL = [RCTConvert NSURL:file];
       NSURL *baseURL = [RCTConvert NSURL:allowingReadAccessToURL];
       [_webView loadFileURL:fileURL allowingReadAccessToURL:baseURL];
       return;
     }
-    
+
     // Check for a static html source first
     NSString *html = [RCTConvert NSString:source[@"html"]];
     if (html) {
@@ -338,7 +342,7 @@ - (void)setSource:(NSDictionary *)source
       [_webView loadHTMLString:html baseURL:baseURL];
       return;
     }
-    
+
     NSURLRequest *request = [RCTConvert NSURLRequest:source];
     // Because of the way React works, as pages redirect, we actually end up
     // passing the redirect urls back here, so we ignore them if trying to load
@@ -391,7 +395,7 @@ - (UIColor *)backgroundColor
                                                                                                  @"canGoBack": @(_webView.canGoBack),
                                                                                                  @"canGoForward" : @(_webView.canGoForward),
                                                                                                  }];
-  
+
   return event;
 }
 
@@ -413,6 +417,20 @@ - (void)observeValueForKeyPath:(NSString *)keyPath
     }
     _onProgress(@{@"progress": [change objectForKey:NSKeyValueChangeNewKey]});
   }
+
+  if ([keyPath isEqualToString:@"canGoBack"]) {
+    if (!_onCanGoBackChange) {
+      return;
+    }
+    _onCanGoBackChange(@{@"canGoBack": [change objectForKey:NSKeyValueChangeNewKey]});
+  }
+
+  if ([keyPath isEqualToString:@"canGoForward"]) {
+    if (!_onCanGoForwardChange) {
+      return;
+    }
+    _onCanGoForwardChange(@{@"canGoForward": [change objectForKey:NSKeyValueChangeNewKey]});
+  }
 }
 
 - (void)dealloc
@@ -468,9 +486,9 @@ - (void)webView:(__unused WKWebView *)webView decidePolicyForNavigationAction:(W
   NSURLRequest *request = navigationAction.request;
   NSURL* url = request.URL;
   NSString* scheme = url.scheme;
-  
+
   BOOL isJSNavigation = [scheme isEqualToString:RCTJSNavigationScheme];
-  
+
   // handle mailto and tel schemes
   if ([scheme isEqualToString:@"mailto"] || [scheme isEqualToString:@"tel"]) {
     if ([app canOpenURL:url]) {
@@ -479,7 +497,7 @@ - (void)webView:(__unused WKWebView *)webView decidePolicyForNavigationAction:(W
       return;
     }
   }
-  
+
   // skip this for the JS Navigation handler
   if (!isJSNavigation && _onShouldStartLoadWithRequest) {
     NSMutableDictionary<NSString *, id> *event = [self baseEvent];
@@ -493,7 +511,7 @@ - (void)webView:(__unused WKWebView *)webView decidePolicyForNavigationAction:(W
       return decisionHandler(WKNavigationActionPolicyCancel);
     }
   }
-  
+
   if (_onLoadingStart) {
     // We have this check to filter out iframe requests and whatnot
     BOOL isTopFrame = [url isEqual:request.mainDocumentURL];
@@ -506,7 +524,7 @@ - (void)webView:(__unused WKWebView *)webView decidePolicyForNavigationAction:(W
       _onLoadingStart(event);
     }
   }
-  
+
   if (isJSNavigation) {
     decisionHandler(WKNavigationActionPolicyCancel);
   }
@@ -525,7 +543,7 @@ - (void)webView:(__unused WKWebView *)webView didFailProvisionalNavigation:(__un
       // http://stackoverflow.com/questions/1024748/how-do-i-fix-nsurlerrordomain-error-999-in-iphone-3-0-os
       return;
     }
-    
+
     NSMutableDictionary<NSString *, id> *event = [self baseEvent];
     [event addEntriesFromDictionary:@{
                                       @"domain": error.domain,
@@ -548,7 +566,7 @@ - (void)webView:(WKWebView *)webView didFinishNavigation:(__unused WKNavigation
 
 - (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler {
   UIAlertController *alertController = [UIAlertController alertControllerWithTitle:message message:nil preferredStyle:UIAlertControllerStyleAlert];
-  
+
   [alertController addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"Close", nil) style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
     completionHandler();
   }]];
@@ -557,7 +575,7 @@ - (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSStrin
 }
 
 - (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL))completionHandler {
-  
+
   // TODO We have to think message to confirm "YES"
   UIAlertController *alertController = [UIAlertController alertControllerWithTitle:message message:nil preferredStyle:UIAlertControllerStyleAlert];
   [alertController addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"OK", nil) style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
@@ -571,17 +589,17 @@ - (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSStr
 }
 
 - (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString *))completionHandler {
-  
+
   UIAlertController *alertController = [UIAlertController alertControllerWithTitle:prompt message:nil preferredStyle:UIAlertControllerStyleAlert];
   [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
     textField.text = defaultText;
   }];
-  
+
   [alertController addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"OK", nil) style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
     NSString *input = ((UITextField *)alertController.textFields.firstObject).text;
     completionHandler(input);
   }]];
-  
+
   [alertController addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"Cancel", nil) style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
     completionHandler(nil);
   }]];

ios/RCTWKWebView/CRAWKWebViewManager.m

@@ -67,6 +67,8 @@ - (UIView *)view
 RCT_EXPORT_VIEW_PROPERTY(onLoadingError, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onShouldStartLoadWithRequest, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onProgress, RCTDirectEventBlock)
+RCT_EXPORT_VIEW_PROPERTY(onCanGoBackChange, RCTDirectEventBlock)
+RCT_EXPORT_VIEW_PROPERTY(onCanGoForwardChange, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onMessage, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(onScroll, RCTDirectEventBlock)
 RCT_EXPORT_VIEW_PROPERTY(hideKeyboardAccessoryView, BOOL)