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POWhy a separate instance of ViewController Class is affecting previous instance?
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copied!<p><strong>UPDATE - Cause found!</strong>... please read below & suggest the solution:</p> <p>While creating a video to show this issue, I have found why does that happen...</p> <p>Any Control/Element that is defined between <code>#imports</code> & <code>@implementation DetailViewController</code> in <code>.m</code> file is lost by the original detVC when a new instance is created of VC.</p> <p><em>Example:</em> I am including a video that re-creates this issue. As shown, all controls work except a <code>UISegmentedControl</code> & a <code>UILabel</code>.. both of which are defined in <code>DetailViewController.m</code> as:</p> <pre><code>#import "DetailViewController.h" UISegmentedControl *sortcontrol; UILabel *incrementLabel; @implementation DetailViewController </code></pre> <p><strong>Video Link</strong> - <a href="http://www.youtube.com/watch?v=2ABdK0LkGiA" rel="nofollow">http://www.youtube.com/watch?v=2ABdK0LkGiA</a></p> <p>I think we are pretty close.. Waiting for the answer!!</p> <p>P.S.: I think this info is enough can lead us to the solution, but if needed I can share the code too.</p> <hr> <p>EARLIER:</p> <p>There's a detailViewController (detVC) in our app which is normally 'pushed' from a UITableViewController.</p> <p>Now we are also implementing Push Notifications which would 'modally' present the same detVC whenever the notification arrives, which in turn can happen over any view controller.</p> <p>It works all fine until the detVC through notification is presented while another instance of detVC was already the active view controller (pushed earlier through TableView).</p> <p>The problem happens when the presented detVC is dismissed - the pushed detVC 'looses' control of about everything - It is not pointing to the same data as earlier & even the <code>UISegmentedControl</code> on Navigation Toolbar points to <code>-1</code> index on pressing any index!</p> <p>Why does such thing happen when we are creating a separate instance of detVC? Why does it affect the earlier detVC? How can it be resolved / What about Objective C needs to be learned here? (FYI, we are using ARC in the project)</p> <p>Thanks</p> <hr> <p>EDIT - Some code:</p> <p>When Pushed:</p> <pre><code>ProductDetailViewController *detailViewController = [[ProductDetailViewController alloc] init]; detailViewController.hidesBottomBarWhenPushed = YES; [self.navigationController pushViewController:detailViewController animated:YES]; detailViewController.serverOffset=serverOffset; detailViewController.prdctIndex = indexPath.row; </code></pre> <p>When presented through Notification:</p> <pre><code>- (void)displaySingleProduct:(NSDictionary*)userInfo{ ProductDetailViewController *onePrdVC = [[ProductDetailViewController alloc] init]; UINavigationController *addNav = [[UINavigationController alloc] initWithRootViewController:onePrdVC]; onePrdVC.justOne=YES; onePrdVC.onePrdIDtoLoad=[[[userInfo valueForKey:@"prd"] valueForKey:@"id"] intValue]; [self.navigationController presentModalViewController:addNav animated:YES]; } </code></pre> <p>There is a <code>Product</code> class in detVC which gets the data from the values stored at the prdctIndex row in the SQLite table.</p> <p>After dismissing the presented detVC through notification, the <code>Product</code> class of the pushed detVC starts pointing to the row which was used for <code>Product</code> class in presented detVC. And there is no such code in <code>viewDidAppear</code> which would alter <code>Product</code> class.</p> <p>So, this, <code>UISegmentedControl</code> issue mentioned above & some other problems are causing the pain! Basically, the whole detVC acts weird - which re-works if we just pop & re-push it!</p> <hr> <p><strong>EDIT 2</strong></p> <p>I have more info on it which could lead to the cause. If I run <code>viewDidLoad</code> on <code>viewDidAppear</code> like this:</p> <pre><code>if (!justOne) { aProduct = [allProducts getProduct:(prdctIndex+1) one:NO]; [self viewDidLoad]; [self populateDetails]; } </code></pre> <p>the pushed detVC regains the control & every element/control starts re-working as expected (but not in the ideal way). So, it is quite clear that the separate instance of presented detVC does messes up the earlier pushed detVC & a re-setting up of all the controls / pointers is required through <code>viewDidLoad</code>.</p> <p>Can any helpful conclusion can be derived from this info?</p>

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