Question

I followed the steps in ‘Your Second iOS App’ tutorial from iOS developer library, complied and ran in iPhone simulator. The application allows me to add new birds, but does not allow me to navigate from Bird Sightings scene to Bird Sighting Detail screen.Any idea on what needs to be done. I reviewed the steps and cannot quickly identify the problem. Appreciate your help and steps to debug. (BTW, I am learning to debug in Xcode IDE). The link to tutorial is http://developer.apple.com/library/ios/#documentation/iPhone/Conceptual/SecondiOSAppTutorial/GettingStarted/GettingStarted.html#//apple_ref/doc/uid/TP40011318-CH2-SW3

Thanks

//  BirdsAppDelegate.h  
#import <UIKit/UIKit.h>
@interface BirdsAppDelegate : UIResponder <UIApplicationDelegate>
@property (strong, nonatomic) UIWindow *window;
@end

//  BirdsAppDelegate.m
#import "BirdsAppDelegate.h"
#import "BirdSightingDataController.h"
#import "BirdsMasterViewController.h"

@implementation BirdsAppDelegate

@synthesize window = _window;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    UINavigationController *navigationController = (UINavigationController *)self.window.rootViewController;
    BirdsMasterViewController *firstViewController = (BirdsMasterViewController *)[[navigationController viewControllers] objectAtIndex:0];

    BirdSightingDataController *aDataController = [[BirdSightingDataController alloc] init];
    firstViewController.dataController = aDataController;
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
{
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
}

@end

//  BirdsMasterViewController.h
#import <UIKit/UIKit.h>
@class BirdSightingDataController;
@interface BirdsMasterViewController : UITableViewController
@property (strong, nonatomic) BirdSightingDataController *dataController;

@end

//  BirdsMasterViewController.m
#import "BirdsMasterViewController.h"
#import "BirdSightingDataController.h"
#import "BirdSighting.h"
#import "BirdsDetailViewController.h"
#import "AddSightingViewController.h"
@interface BirdsMasterViewController () <AddSightingViewControllerDelegate>
@end

@implementation BirdsMasterViewController
@synthesize dataController = _dataController;

- (void)awakeFromNib
{
    [super awakeFromNib];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

- (void)addSightingViewControllerDidCancel:(AddSightingViewController *)controller {
    [self dismissViewControllerAnimated:YES completion:NULL];
}

- (void)addSightingViewControllerDidFinish:(AddSightingViewController *)controller name:(NSString *)name location:(NSString *)location {
    if ([name length] || [location length]) {
        [self.dataController addBirdSightingWithName:name location:location];
        [[self tableView] reloadData];
    }
    [self dismissModalViewControllerAnimated:YES];
}

#pragma mark - Table View

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self.dataController countOfList];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"BirdSightingCell";

    static NSDateFormatter *formatter = nil;
    if (formatter == nil) {
        formatter = [[NSDateFormatter alloc] init];
        [formatter setDateStyle:NSDateFormatterMediumStyle];
    }
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    BirdSighting *sightingAtIndex = [self.dataController objectInListAtIndex:indexPath.row];
    [[cell textLabel] setText:sightingAtIndex.name];
    [[cell detailTextLabel] setText:[formatter stringFromDate:(NSDate *)sightingAtIndex.date]];
    return cell;
}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.
    return NO;
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([[segue identifier] isEqualToString:@"ShowSightingDetails"]) {
        BirdsDetailViewController *detailViewController = [segue destinationViewController];

        detailViewController.sighting = [self.dataController objectInListAtIndex:[self.tableView indexPathForSelectedRow].row];
    }else if ([[segue identifier] isEqualToString:@"ShowAddSightingView"]) {
        AddSightingViewController *addController = (AddSightingViewController *)[[[segue destinationViewController] viewControllers] objectAtIndex:0];
        addController.delegate = self;
    }
}
@end

//  BirdsDetailViewController.h
#import <UIKit/UIKit.h>
@class BirdSighting;

@interface BirdsDetailViewController : UITableViewController

@property (strong, nonatomic) BirdSighting *sighting;
@property (weak, nonatomic) IBOutlet UILabel *birdNameLabel;
@property (weak, nonatomic) IBOutlet UILabel *locationLabel;
@property (weak, nonatomic) IBOutlet UILabel *dateLabel;

@end


//  BirdsDetailViewController.m
#import "BirdsDetailViewController.h"
#import "BirdSighting.h"

@interface BirdsDetailViewController ()
- (void)configureView;
@end

@implementation BirdsDetailViewController

@synthesize sighting = _sighting, birdNameLabel = _birdNameLabel, locationLabel = _locationLabel, dateLabel = _dateLabel;

#pragma mark - Managing the detail item
- (void)setSighting:(BirdSighting *) newSighting
{
    if (_sighting != newSighting) {
        _sighting = newSighting;

        // Update the view.
        [self configureView];
    }
}

- (void)configureView
{
    // Update the user interface for the detail item.
    // Update the user interface for the detail item.
    BirdSighting *theSighting = self.sighting;

    static NSDateFormatter *formatter = nil;
    if (formatter == nil) {
        formatter = [[NSDateFormatter alloc] init];
        [formatter setDateStyle:NSDateFormatterMediumStyle];
    }
    if (theSighting) {
        self.birdNameLabel.text = theSighting.name;
        self.locationLabel.text = theSighting.location;
        self.dateLabel.text = [formatter stringFromDate:(NSDate *)theSighting.date];
    }   
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    [self configureView];
}

- (void)viewDidUnload
{
    self.sighting = nil;
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

@end

Answer 1

I have encountered the same problem, here’s the solution I found:

1. Ensure you segure (control+drag) is generated from TableViewCell (NOT MasterViewController) to BirdsDetailViewController.
   Reference: “control-drag from the table cell in the master scene to the detail scene” in the tutorial: Design the Detail Scene.
2. Ensure your master view class is set to BirdsMasterViewController, NOT default UITableViewController, and detail view class is BirdsDetailViewController, NOT default UITableViewController.
   You can check them in indentity inspector after selected master/detail view.
3. Ensure your Table View Cell indentifier is the same as in your BirdSightingCell.

For more details see this link.