Question

I find this sample code and i modified the code to make it do what i want.
The tableview load data from a plist, it works
datas are displayed in sections, it works
now when a row is selected, i want to push a Detailviewcontroller to show more details.
Grrrr, it does not work, and i don’t know why.
The difference between this code and a other one where it works fine, is that ICB_SectionedTableViewDemoViewController is declared as a class in the appDelegate and i don’t know if it as an incidence when i want to push the DetailViewController.

here is the code of my rootController named ICB_SectionedTableViewDemoViewController.m

//  ICB_SectionedTableViewDemoViewController.m
//  ICB_SectionedTableViewDemo
//
//  Created by Matt Tuzzolo on 12/10/10.
//  Copyright 2010 ELC Technologies. All rights reserved.
//

#import "ICB_SectionedTableViewDemoViewController.h"
#import "ICB_SectionedTableViewDemoAppDelegate.h"
#import "DetailViewController.h"



@implementation ICB_SectionedTableViewDemoViewController

@synthesize books, sections ;

- (void)viewDidLoad {

    self.books = [NSMutableArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"books" ofType:@"plist"]];
    self.sections = [[NSMutableDictionary alloc] init];

    BOOL found;

    // Loop through the books and create our keys
    for (NSDictionary *book in self.books)
    {        
        NSString *c = [[book objectForKey:@"author"] substringToIndex:1];

        found = NO;

        for (NSString *str in [self.sections allKeys])
        {
            if ([str isEqualToString:c])
            {
                found = YES;
            }
        }

        if (!found)
        {     
            [self.sections setValue:[[NSMutableArray alloc] init] forKey:c];
        }
    }

    // Loop again and sort the books into their respective keys
    for (NSDictionary *book in self.books)
    {
        [[self.sections objectForKey:[[book objectForKey:@"author"] substringToIndex:1]] addObject:book];
    }    

    // Sort each section array
    for (NSString *key in [self.sections allKeys])
    {
        [[self.sections objectForKey:key] sortUsingDescriptors:[NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"author" ascending:YES]]];
    }    

    [super viewDidLoad];
}

#pragma mark -
#pragma mark Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
{
    return [[self.sections allKeys] count];
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{    
    if(section == 0)
        return @"COULEURS";
    else
        return @"MOTIFS";    

  //  return [[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:section];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{
    return [[self.sections valueForKey:[[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:section]] count];
}

- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
    return [[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];
}

// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
    }

    NSDictionary *book = [[self.sections valueForKey:[[[self.sections allKeys] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)] objectAtIndex:indexPath.section]] objectAtIndex:indexPath.row];

    cell.textLabel.text = [book objectForKey:@"title"];    
    cell.detailTextLabel.text = [book objectForKey:@"description"];

    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {



    //Initialize the detail view controller and display it.
    DetailViewController *dvController = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:[NSBundle mainBundle]];
    dvController.CL = [self.books objectAtIndex:indexPath.row];
    [self.navigationController pushViewController:dvController animated:YES];
 //   [self presentModalViewController:dvController animated:YES];
 //   [self.view addSubview:dvController.view];
    [dvController release];



}


- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


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

@end

thanks for your very useful help and remind that i’m beginner and my first language is Franch.

Answer 1

After having a look at the project, it seems that you did not create a UINavigationController. So, I suggest you to use this code for application:didFinishLaunchingWithOptions::

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    UINavigationController* navigation = [[UINavigationController alloc] init];
    [navigation pushViewController:viewController animated:NO];
    [window addSubview:navigation.view];

    [self.window makeKeyAndVisible];

    return YES;
 }

Here, a UINavigationController is instantiated and your first (root) controller is pushed on to it.

Important: your app has more problems, so it will not work, but at least your DetailView controller will be loaded and attempted to display. About the issues I found:

1. in didSelectRowAtIndexPath you are using the wrong nib name;

2. in DetailViewController‘s viewDidLoad you are using a property CL.title which is not defined;

once you fix those problems, possibly the detail view will show up.

OLD ANSWER:

Set a breakpoint in tableView:didSelectRowAtIndexPath: and check that your DetailViewController is created correctly and also that self.navigationController is not nil.

Alternatively you can add NSLog traces to your code (this is an important debugging technique):

 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    //Initialize the detail view controller and display it.
    DetailViewController *dvController = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:[NSBundle mainBundle]];
    dvController.CL = [self.books objectAtIndex:indexPath.row];
    [self.navigationController pushViewController:dvController animated:YES];

    NSLog(@"navController: %@", [self.navigationController description]);
    NSLog(@"dvController.CL: %@", [dvController.CL description]);


 //   [self presentModalViewController:dvController animated:YES];
 //   [self.view addSubview:dvController.view];
   [dvController release];

}