Leaks when adding-removing objects to a MutableArray

Question

Hi guys,

i have a memory leak in my app. My app launches on a tableviewcontroller. i parse a json file to fill an array. Then this array is used to fill the tableview's cells. I fill my array with objects (class).

I do:

[tab_Demandes removeAllObjects];

for (NSDictionary *demandeD in demandes)

{
    Demande *dem =[[Demande alloc] init];

    dem.demTitle=title;

    dem.demId=Id;

    dem.demCreated=created;

    [tab_Demandes addObject:dem];

    [dem release];
}

My array and tableview are filled at launch, no problem. if i hit a table cell and then want to come back on the tableview my app crash on :

[tab_Demandes removeAllObjects];

If i dont do [dem release] i have leaks in instruments every time i reload tab_Demandes. RemoveAllObjects works but i have leaks.

Thx for any help as usual.

Wallou ++

Edit : here is where i made my cells. Maybe i mess up when creating the cells Actually tab_Demandes is declared in the delegate with get/set to access it from other classes (where i load my tableviewcontroller).

(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

static NSString *CellIdentifier = @"Cell";

CustomCellViewController *cell = (CustomCellViewController *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
   // NSLog(@"Cell created");
    NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"CustomCellViewController" owner:nil options:nil];

    for(id currentObject in topLevelObjects)
    {
        if([currentObject isKindOfClass:[CustomCellViewController class]])
        {
            cell = (CustomCellViewController *)currentObject;
            break;
        }
    }
}

    // Set up the cell...


    TabsAppDelegate *appDelegate = (TabsAppDelegate*)[[UIApplication sharedApplication] delegate];

    cell.lbl_demId.text=[NSString stringWithFormat:@"%@", [[[appDelegate tab_Demandes] objectAtIndex:indexPath.row ] demId]];
    cell.lbl_demCopro .text=[NSString stringWithFormat:@"%@", [[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demIdCopro ]];
    cell.lbl_demImmeuble.text=[NSString stringWithFormat:@"%@", [[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demIdImmeuble]];
    cell.lbl_demLot.text=[NSString stringWithFormat:@"%@", [[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demIdLot]];
    cell.lbl_demDescriptif.text=[NSString stringWithFormat:@"%@", [[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demTitle]];
    //NSLog(@"statut demande : %@",[[tab_Demandes objectAtIndex:indexPath.row] demStatut]);
    if ([[[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demStatut] isEqualToString: @"Validée"])
    {
    cell.lbl_ImageView.image=[UIImage imageNamed:@"VDEM2.png"];
    }
    if([[[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demStatut] isEqualToString: @"Initiée"])
    {
       cell.lbl_ImageView.image=[UIImage imageNamed:@"IDEM.png"];
    }
    if([[[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demStatut] isEqualToString: @"Terminée"])
    {
    cell.lbl_ImageView.image=[UIImage imageNamed:@"TDEM.png"];
    }
    if([[[[appDelegate tab_Demandes] objectAtIndex:indexPath.row] demStatut] isEqualToString: @"En coursée"])
    {
    cell.lbl_ImageView.image=[UIImage imageNamed:@"EDEM.png"];
    }


return cell;    

}

NEW EDIT:

Demandes.h:

@interface Demande : NSObject { 

    NSString *demId;
    NSString *demStatut;
    NSString *demTitle;
    NSString *demCreated;
    NSString *demIdCopro;
    NSString *demIdImmeuble;
    NSString *demIdLot;
    NSString *demDescriptif;
    NSString *demAuteur;
    NSString *demIdAuteur;
    NSString *demLoginAuteur;   
}

@property (retain,nonatomic) NSString *demId;
@property (retain,nonatomic) NSString *demIdCopro;
@property (retain,nonatomic) NSString *demIdImmeuble;
@property (retain,nonatomic) NSString *demIdLot;
@property (retain,nonatomic) NSString *demDescriptif;
@property (retain,nonatomic) NSString *demStatut;
@property (retain,nonatomic) NSString *demTitle;
@property (retain,nonatomic) NSString *demCreated;
@property (retain,nonatomic) NSString *demAuteur;
@property (retain,nonatomic) NSString *demIdAuteur;
@property (retain,nonatomic) NSString *demLoginAuteur;
@end

Demandes.m:

import "Demande.h"
@implementation Demande


@synthesize demId,demIdCopro,demIdImmeuble,demIdLot,demDescriptif,demStatut,demTitle,demCreated,demAuteur,demIdAuteur,demLoginAuteur;


- (void)dealloc {   
    [demId release];
    [demIdCopro release];
    [demId release];
    [demIdImmeuble release];
    [demIdLot release];
    [demDescriptif release];
    [demStatut release];
    [demTitle release];
    [demCreated release];
    [demAuteur release];
    [demIdAuteur release];
    [demLoginAuteur release];
    [super dealloc];
}
@end

Answer 1

I guess you should use [tab_Demandes addObject:[dem autorelease]]; instead of:

[tab_Demandes addObject:dem];
[dem release];

as stated here

Answer 2

The code above is correct. I wondering if you don't over release objects that are in you array (i.e. during tableView:cellForRowAtIndexPath method). When calling removeAllObject, the method release every object it removes. If one object is already released and deallocated, you app will crash.

Proposed Optimization :

-Be sure that the cellIdentifier in the nib is well @"Cell"

-Replace

cell.lbl_demId.text=[NSString stringWithFormat:@"%@", [[[appDelegate tab_Demandes] objectAtIndex:indexPath.row ] demId]];

by

Demand* dem = [[[appDelegate tab_Demandes] objectAtIndex:indexPath.row ];
cell.lbl_demId.text=[NSString stringWithFormat:@"%@", [dem demId]];

to avoid querying the array too much time.

-Avoid placing your model in the appDelegate and create a singleton model object instead. This is a common beginner design mistake driven by the fact that the appDelegate is an easy object to customize and access to avoid passing you model to every objects.