NSMutableArray in AppDelegate addObject from an IBAction

[iambounty]

Hello all.
I've been trying to add a simple bookmarks facility to my app for my dissertation at uni. Im new to iPhone development so really I don't understand whats happening.

What im trying to do is add an object (string) to the array but what I've done doesnt work at all.

I got my array set up in my AppDelegate and it populates a table view in the BookmarksViewController.m file.

My application consists of a tab bar and navigation bar but I've chopped all that out here to make it easier to read.

Here is the code:

SETTING UP THE ARRAY

DissertationAppDelegate.h

#import <UIKit/UIKit.h>

@class DissertationViewController;

@interface DissertationAppDelegate : NSObject <UIApplicationDelegate> {
	
	NSMutableArray *array;

    UIWindow *window;
    DissertationViewController *viewController;
}

@property (nonatomic, retain) UIWindow *window;

@property (nonatomic, retain) NSMutableArray *array;

@end

DissertationAppDelegate.m

#import "DissertationAppDelegate.h"

@implementation DissertationAppDelegate

@synthesize window;

@synthesize array;

#pragma mark -
#pragma mark Application lifecycle

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *) launchOptions {    
    
	NSArray *paths = NSSearchPathForDirectoriesInDomains
	(NSDocumentDirectory, NSUserDomainMask, YES);
	NSString *documentsDirectory = [paths objectAtIndex:0];
	
	NSString *fullFileName = [NSString stringWithFormat:@"%@/arraySaveFile", documentsDirectory];
	
	array = [[NSMutableArray alloc] init];
	[array addObject:@"One"];
	[array addObject:@"Two"];
	[array addObject:@"Three"];
	

	[array writeToFile:fullFileName atomically:NO];
	
    [self.window makeKeyAndVisible];
}

POPULATING THE TABLE VIEW WITH THE ARRAY

BookmarksViewController.h

@interface BookmarksViewController : UITableViewController {
	NSMutableArray *bookmarksArray;
}

@property (nonatomic, retain) NSMutableArray *bookmarksArray;

BookmarksViewController.m

#import "BookmarksViewController.h"
@synthesize bookmarksArray;
- (void)viewDidLoad {
	
	NSArray *paths = NSSearchPathForDirectoriesInDomains
	(NSDocumentDirectory, NSUserDomainMask, YES);
	NSString *documentsDirectory = [paths objectAtIndex:0];

	NSString *fullFileName = [NSString stringWithFormat:@"%@/arraySaveFile", documentsDirectory];
	NSMutableArray *array = [[NSMutableArray alloc] initWithContentsOfFile:fullFileName];

	bookmarksArray = array;
	

[self.tableView reloadData];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
	return [bookmarksArray count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    
    static NSString *CellIdentifier = @"Cell";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }
    
    // Configure the cell...

	 
	  cell.textLabel.text = [bookmarksArray objectAtIndex:indexPath.row];
    return cell;
}

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

PERFORMING THE IBACTION FROM ANOTHER VIEW CONTROLLER

Header File

-(IBAction) pushChap01Bookmark:(id)sender;

Implementation File

-(IBAction) pushChap01Bookmark:(id)sender{

	DissertationAppDelegate *appDelegate = (DissertationAppDelegate *)[[UIApplication sharedApplication] delegate];
	appDelegate.array = [[NSMutableArray alloc] init];
	[appDelegate.array addObject:@"THIS IS WHAT I WANT TO ADD"];

	[self.navigationController pushViewController:bookmarksViewController animated:YES];
	bookmarksViewController.title = @"Bookmarks";
	
}

Okkkkkkkkk.... So when you push the button I wanted it to add to the array in the app delegate and push the BookmarksViewController onto the navigation stack, and update the table. It does everything except for adding the object to the array.

If there is anyone out there who knows whats wrong then can you please help me out. I will appreciate it very much.

Thank you

[musicwind95]

Unless you have to, don't do the setup in the app delegate. Instead, in your viewDidLoad method, check to see if the file exists first:

NSFileManager fm = [NSFileManager defaultManager];
if (fm fileExistsAtPath:fullFileName)
// Load data
else
// Create new array

Make sure to use NSString's stringByAppendPathComponent: method. It's better guaranteed to generate a valid path string.

Finally, make sure to use your setter:
self.bookmarksArray = array; Otherwise, at the very least bookmarksArray will point to array, so anything that happens to array will also happen to bookmarksArray. This could lead to odd issues later on.