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copied!<p>The download link on the page you linked to doesn't work, so I'll keep my answer more general. </p> <p>You don't need to keep multiple WebViews or manually generate snapshots if you're using <code>NSPageController</code>; it takes care of that for you. In your case, you want to use <code>NSPageController</code> in <a href="http://developer.apple.com/library/Mac/documentation/AppKit/Reference/NSPageController_Class/Reference/Reference.html#//apple_ref/doc/uid/TP40012265-CH1-SW19" rel="noreferrer">History Mode</a>. To do that, wire your <code>WebView</code> to <code>pageController.view</code>. You will need to implement three <code>NSPageControllerDelegate</code> methods:</p> <pre><code>- (void)pageControllerWillStartLiveTransition:(NSPageController *)pageController; - (void)pageController:(NSPageController *)pageController didTransitionToObject:(id)object; - (void)pageControllerDidEndLiveTransition:(NSPageController *)pageController; </code></pre> <p>Every time the WebView goes to a new page (not through a back/forward action), call <a href="http://developer.apple.com/library/Mac/documentation/AppKit/Reference/NSPageController_Class/Reference/Reference.html#//apple_ref/doc/uid/TP40012265-CH1-SW14" rel="noreferrer"><code>navigateForwardToObject:(id)object</code></a> on the <code>pageController</code>. I would make <code>object</code> a custom object that stores user state for a navigated page (scroll positions, highlighted text, form contents, etc.) as well as the page's <a href="https://developer.apple.com/library/mac/documentation/Cocoa/Reference/WebKit/Classes/WebHistoryItem_Class/Reference/Reference.html#//apple_ref/doc/c_ref/WebHistoryItem" rel="noreferrer"><code>WebHistoryItem</code></a>. The user state can be undefined initially, but should get set in <code>pageControllerWillStartLiveTransition:</code>. Here's an example:</p> <pre><code>- (void)pageControllerWillStartLiveTransition:(NSPageController *)pageController { // Remember user state MyCustomObject *object = [self.pageController.arrangedObjects objectAtIndex:self.pageController.selectedIndex]; object.userState = someUserState; } </code></pre> <p>When that method returns, the <code>pageController</code> will hide its view (the WebView) and display snapshots of previous states of its view instead. </p> <p>Once the swiping animation is complete, <code>pageController:didTransitionToObject:</code> will get called. Cool. What you should do in that method is grab the <code>WebHistoryItem</code> out of <code>object</code> and have the WebView go back to that item using the <a href="https://developer.apple.com/library/mac/documentation/Cocoa/Reference/WebKit/Classes/WebView_Class/Reference/Reference.html#//apple_ref/doc/uid/20001903-BABFADDF" rel="noreferrer"><code>goToBackForwardItem:</code></a> method. You should also hold onto the user state you stored in <code>object</code> (say, in an instance variable), because you'll need to restore it once <code>WebView</code> finishes loading.</p> <p>Lastly, in <code>pageControllerDidEndLiveTransition:</code> you do anything you want done before redisplaying the WebView. I expect that would be nothing, since the user state isn't restored until the WebView finishes loading, so all you would need in its implementation would be <code>[pageController completeTransition]</code>. </p> <p>One last detail is the back/forward buttons. You should implement them as you would normally, but also have them call <code>navigateBack:</code> or <code>navigateForward:</code> on the pageController. </p> <p>That pretty much covers it. I haven't actually tried this specific example, so let me know if you run into any problems.</p> <h2>Edit</h2> <p>Here's how I'd modify your source to get basic <code>NSPageController</code> functionality. Add an <code>NSPageController IBOutlet</code> property in your AppDelegate header file. In your <code>MainMenu.xib</code> file add the page controller, wire its view to your WebView, make your AppDelegate its delegate, and give it a referencing outlet to the property we just created in the AppDelegate. Also, make your AppDelegate your WebView's <code>frameLoadDelegate</code>. Inside <code>basicWebAppDelegate.m</code> add a private property:</p> <pre><code>@interface basicWebAppDelegate () @property (assign) id currentItem; @end </code></pre> <p>Then add the following inside implementation:</p> <pre><code>#pragma mark - WebFrameLoadDelegate - (void)webView:(WebView *)sender didCommitLoadForFrame:(WebFrame *)frame { if (frame == [sender mainFrame]) { id object = [sender.backForwardList currentItem]; BOOL isCurrentItem = self.currentItem && (object == self.currentItem) ? YES : NO; if (!isCurrentItem) { [self.pageController navigateForwardToObject:[sender.backForwardList currentItem]]; } } } #pragma mark - NSPageControllerDelegate - (void)pageControllerWillStartLiveTransition:(NSPageController *)pageController { self.currentItem = [self.webView.backForwardList currentItem]; // Here is where you'll save any state for your pageController.arrangedObjects[pageController.selectedIndex] object } - (void)pageController:(NSPageController *)pageController didTransitionToObject:(id)object { BOOL isCurrentItem = self.currentItem && (object == self.currentItem) ? YES : NO; if (!isCurrentItem) { self.currentItem = object; [self.webView goToBackForwardItem:object]; } } - (void)pageControllerDidEndLiveTransition:(NSPageController *)pageController { self.currentItem = nil; [pageController completeTransition]; } </code></pre> <p>Finally, change your <code>goBack:</code> and <code>goForward:</code> actions to just call <code>[self.pageController navigateBack:sender]</code> and <code>[self.pageController navigateForward:sender]</code>, respectively.</p> <p>Note that I didn't bother saving any user state here and instead used <code>WebHistoryItem</code>s directly as the objects. You might need to do differently.</p> <p>Let me know if you need more help.</p>

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