Iterate over NSMutableArray with indexPath row - EXC_BAD_ACCESS

Question

Hi there,
I recently started developing iPhone applications and I'm currently trying to create an app that displays a forum a friend and me created.
I have created custom classes for categories and forums (basically, they just have properties like the rows in the database), as well as a DataController-Class which is instantiated in the different TableViewControllers. Data is read via XML and stored in a NSMutableArray (I also tried NSMutableDictionary).
This works well for getting the categories, put them in an array/dictionary and display them, given the current indexPath row index.
But when it comes to displaying the forums, my app crashes with an EXCBADACCESS.
Here's some code, I hope it's enough:
ViewController:
- (void)viewDidLoad {
[super viewDidLoad];
dc = [[DataController alloc] init];
[dc initCategoryList];
- (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];
XLog("indexPath row: %d", [indexPath row]);
Category *currentCategory = [[dc CategoryList] categoryAtIndex:[indexPath row] ];
UILabel *labelTitle = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, cellWidth * 0.75, 30) ];
[labelTitle setFont:[UIFont boldSystemFontOfSize:18.0] ];
[labelTitle setText:[currentCategory strcattitle] ]; <-- crashes here
/* do some stuff */
return cell;
CategoryList (replace Category with Board and you have the similar class)
@implementation CategoryList
@synthesize categories;
- (id)init {
if ( self = [super init] ) {
categories = [[NSMutableArray alloc] init];
return self;
- (void)addCategory:(Category *)_Category {
XLog("adding category (%@) at %d...", _Category, [categories count]);
[categories addObject:_Category];
XLog("ok");
- (NSString *)description {
NSMutableString *description = [[NSMutableString alloc] initWithFormat:@"<CategoryList> %d elements\r\n",
[categories count]];
for ( int i = 0; i < [categories count]; i++) {
[description appendFormat:[[categories objectAtIndex:i] description]];
[description appendFormat:@"\r\n"];
return description;
- (Category *)categoryAtIndex:(NSUInteger)index {
return [categories objectAtIndex:index];
- (void)dealloc {
[categories release];
[super dealloc];
Category
@implementation Category
@synthesize id_cat, strcattitle, int_boardcount;
- (id)initWithId:(NSInteger)idcat
title:(NSString *)str_cattitle
boardcount:(NSUInteger)intboardcount {
if ( self = [super init] ) {
id_cat = idcat;
strcattitle = str_cattitle;
int_boardcount = intboardcount;
return self;
- (NSString *)description {
return [NSString stringWithFormat:@"<Category> id_cat = %d, strcattitle = %@, int_boardcount = %d",
id_cat, strcattitle, int_boardcount];
- (void)dealloc {
[strcattitle release];
[super dealloc];
The error occurs when I try to access the objects' properties in the TableViewController. The index of the objects that are stored in the corresponding list seem to be of different types.
P.S.: How do I post code with a fixed font here?
Message was edited by: HoPi`
Message was edited by: HoPi`

Answer 1

I do not see your forum code to comment, but you probably are not trying to access the string field. The other possibility is that the input pointer is still valid (not dealloc'ed elsewhere in your code, but this is something you should never bank on. You can use self.xyz, or [self setXyz] which are complimentary. If you do not want to use the property/accessor, you can copy the input or send a retain message to the variable. Bottom line is you need a retain/copy message to be sent for subsequent access to work.