Question

I have an object that contains a array. On initialization of this object, the array is allocated and properly filled (as I can see in the debugger). This object is use to manage elements in a single view.

My problem is that when I try to call the object a second time, the array (and all other parameter of this object) are nil yet they have a memory address (again as seen in debugger).

This is the .h of the object in question :

#import <Foundation/Foundation.h>

#import "ObjectDef.h"
#import "AbstractNode.h"

@interface RenderingMachine : NSObject
{    
    NSMutableArray* _objectID;    // pair list
    NSMutableArray* _objectList;  // node list
    ObjectDef* _defs;             // definition of pairs

    unsigned int _size;
    unsigned int _edgeSize;

    AbstractNode* _lastNode;
}

-(void) InitializeMachine;
-(bool) AddObjectByIndex:(int)index :(float)x :(float)y :(float)originX :(float)originY;
-(bool) AddObjectByType:(NSString*)type;
-(NSMutableArray*) GetObjectID;
-(NSMutableArray*) GetObjectList;
-(unsigned int) Size;
-(void) DrawAllNode;
-(int) ComputePar;
-(void) ComputeLastEdge:(int)edgeCount;

//+(RenderingMachine*) GetMachine;

@end

My main problem right now is with _defs which is filled in InitDefinitions :

-(void) InitializeMachine
{
    _defs = [[ObjectDef alloc] init];
    [_defs InitDefinitions];
    _objectID = [[NSMutableArray alloc] init];
    _objectList = [[NSMutableArray alloc] init];
    _objectID = [NSMutableArray arrayWithObject:[_defs GetPair:3]]; // adding the field node ID

    AbstractNode* rootNode = [[FieldNode alloc] init];
    _objectList = [NSMutableArray arrayWithObject:rootNode]; // adding the field node as root node

    _size = 1;
    _edgeSize = 0;
}

What I’d like to know is if might be a bad alloc / init call or could it be a problem with the ARC of xcode because this particular file compiles with ARC (the other being ignore with “-fno-objc-arc”).

Also, as mentionned the _defs is problematic, but all the property declared under @interface are having the same problem.

Answer 1

First you create a retained object with _objectID = [[NSMutableArray alloc] init];
and then you overwrite it with an autoreleased one _objectID = [NSMutableArray arrayWithObject:[_defs GetPair:3]];

to add the object better use [_objectID addObject:[_defs GetPair:3]];

same thing with the _objectList Object