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POHow to get drill-down tableviews working?
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  1. POHow to get drill-down tableviews working?
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    copied!<p>I am trying to figure out how to do a table view that drills down. I've manage to go from a table view Cell to a detailed view, and there are plenty of tutorials on how that's done with storyboards. </p> <p>What I am trying to do is list some data in a Table view using a plist - I have that part working fine. What I now want to do is go down a few levels. For example: </p> <pre><code>Top level --&gt; Level 1 --&gt; level 2 --&gt; etc --&gt; detailed view. </code></pre> <p>Right now all I can seem to do is: Top level --> detailed view. </p> <p>I just need to understand how - when tapping on one cell it will load the data for that cell in the next level down - like a category of some sort. </p> <p>I'm using the iOS7 SDK and Xcode 5. </p> <p><strong>Edit:</strong> </p> <p>So I looked at some other tutorials and modified them to my needs - this is what I need to do and what I am doing:</p> <ol> <li>I'm using model objects - they get their data from a Plist, which root object is a Dictionary. </li> <li><p>In the Plist data is like so: </p> <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt; &lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt; &lt;plist version="1.0"&gt; &lt;dict&gt; &lt;key&gt;name&lt;/key&gt; &lt;string&gt;iDevices&lt;/string&gt; &lt;key&gt;devices&lt;/key&gt; &lt;array&gt; &lt;dict&gt; &lt;key&gt;name&lt;/key&gt; &lt;string&gt;iPhones&lt;/string&gt; &lt;key&gt;devices&lt;/key&gt; &lt;array&gt; &lt;dict&gt; &lt;key&gt;name&lt;/key&gt; &lt;string&gt;1St Generation&lt;/string&gt; &lt;/dict&gt; &lt;/array&gt; &lt;/dict&gt; &lt;dict&gt; &lt;key&gt;name&lt;/key&gt; &lt;string&gt;iPads&lt;/string&gt; &lt;key&gt;devices&lt;/key&gt; &lt;array&gt; &lt;dict&gt; &lt;key&gt;name&lt;/key&gt; &lt;string&gt;1St Generation&lt;/string&gt; &lt;/dict&gt; &lt;/array&gt; &lt;/dict&gt; &lt;/array&gt; &lt;/dict&gt; &lt;/plist&gt; </code></pre></li> </ol> <p>So now I loaded the Plist into a custom data object and then I am using this object to populate an NSMutableArray like so: </p> <pre><code>-(void)loadData{ NSString *plistPath = [[NSBundle mainBundle]pathForResource:@"masterDeviceList" ofType:@"plist"]; NSDictionary *deviceListDict = [NSDictionary dictionaryWithContentsOfFile:plistPath]; NSArray *allDevices = deviceListDict[@"devices"]; NSMutableArray *iDevices = [NSMutableArray array]; for (NSDictionary *dictionary in allDevices){ RCDevice *iDevice = [[RCDevice alloc]initWithDictionary:dictionary]; [iDevices addObject:iDevice]; } self.devices = iDevices; } </code></pre> <p>I call this method from my viewDidLoad on root TVC. Data loads correctly. </p> <p><strong>Then I fill the tableView like so:</strong></p> <pre><code>- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { UITableViewCell* cell; RCDevice *iDevice = self.devices[indexPath.row]; if (iDevice.device) { cell = [tableView dequeueReusableCellWithIdentifier:LoopBackCell]; } else { cell = [tableView dequeueReusableCellWithIdentifier:DetailCell]; } cell.textLabel.text = iDevice.name; return cell; } </code></pre> <p><strong>Then this is where I am getting stuck:</strong> </p> <pre><code> - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { UITableViewCell *cell = (UITableViewCell *)sender; NSIndexPath *indexPath = [self.tableView indexPathForCell:cell]; NSDictionary *rowData = self.devices[indexPath.row]; //Testing with this type RCDevice *iDevice = self.devices[indexPath.row]; //Also testing with custom object if ([self.devices[indexPath.row]isKindOfClass:[NSDictionary class]]) { if ([segue.identifier isEqualToString:@"loopbackSegue"]) { RCDeviceListView *rcDeviceListVC = (RCDeviceListView *)segue.destinationViewController; //TODO: Check if this gets called }else if ([segue.identifier isEqualToString:@"detailSegue"]){ __unused RCDeviceDetailView *rcDeviceDVC = (RCDeviceDetailView *)segue.destinationViewController; //TODO Fille this in! } } else { if ([self.devices[indexPath.row]isKindOfClass:[RCDevice class]]) { if ([segue.identifier isEqualToString:@"loopbackSegue"]) { RCDeviceListView *rcDeviceListVC = (RCDeviceListView *)segue.destinationViewController; rcDeviceListVC.devices = iDevice.device; //This crashes rcDeviceListVC.devices = rowData[@"devices"]; //Also crashes rcDeviceListVC.title = iDevice.name; }else if ([segue.identifier isEqualToString:@"detailSegue"]){ __unused RCDeviceDetailView *rcDeviceDVC = (RCDeviceDetailView *)segue.destinationViewController; } } //TODO Fille this is! } } </code></pre> <p><strong>The app crashes with this line:</strong></p> <pre><code>rcDeviceListVC.devices = rowData[@"devices"]; </code></pre> <p><strong>The error I get:</strong> </p> <blockquote> <p>[*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[RCDevice objectForKeyedSubscript:]: unrecognized selector sent to instance 0xed4aff0'</p> </blockquote> <p><strong>Which I see why -I think:</strong></p> <blockquote> <p>rcDeviceListVC.devices</p> </blockquote> <p>Is an array filled with RCDevice objects from my loadData method - it doesn't know what <code>rowData[@"devices"]</code> is. </p> <p><strong>So I tried to modify that with this:</strong> </p> <pre><code>rcDeviceListVC.devices = iDevice.device; </code></pre> <p>But that means I have an incompatible pointer. (NSString to an NSArray) </p> <p>I am not sure how to fix this. I think it's because I don't fully understand what the prepareForSegue method is doing? </p> <p>For the actual drill down - I am using a loopback segue and reusing the RCDDeviceListVC. </p> <p><strong>What the app does now:</strong></p> <ol> <li>It loads with the correct data in a Tableview. When I select a cell - the prepareForSegue method gets called - app crashes. </li> </ol> <p>Or</p> <ol start="2"> <li>It reloads the table view with the top level data and has a never ending drill down (loop) </li> </ol> <p><strong>What I want the app to do:</strong></p> <p>Load the first tableview with the data it's using now (iPhones, iPads) - tapping on a cell would list models of either iPads or the iPhones. </p> <p>What am I doing wrong?</p> <p><strong>Update</strong>: </p> <p>This is the original code sample I tried to edit to use with my custom objects - instead of using NSDictionaries. </p> <p>I tested out this code sample with my Plist and it works exactly as I need it to: </p> <pre><code>- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { UITableViewCell* cell = (UITableViewCell*)sender; NSIndexPath* indexPath = [self.tableView indexPathForCell:cell]; NSDictionary* rowData = [self.items objectAtIndex:indexPath.row]; if ([segue.identifier isEqualToString:@"loopbackSegue"]) { DrillTableController* drillVC = (DrillTableController*)segue.destinationViewController; drillVC.items = [rowData objectForKey:@"items"]; drillVC.title = [rowData objectForKey:@"name"]; } else if ([segue.identifier isEqualToString:@"detailSegue"]) { DetailsController* detailVC = (DetailsController*)segue.destinationViewController; detailVC.name = [rowData objectForKey:@"name"]; //detailVC.imageName = [rowData objectForKey:@"imageName"]; } } </code></pre> <p>Why does it work with the above - but not when I try use my custom object? </p> <blockquote> <p>RCDevice</p> </blockquote>
 

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