Question

Ok. I have a class “Game”, which creates an instance of my class “Board”, and tests it.

The “Board” class has a dictionary, which seems to somehow not being able to keep it’s values(?)
Tried to strap down the code to the minimal:

The Game class:

@interface Game : UIViewController{
    Board *board;
}
-(void)testAgain; 

@implementation Game
-(void)setup{
    board = [Board alloc]createBoard];
    [board test]; //returns right value
    [self testAgain]; //returns (null), see output below
}
-(void)testAgain{
    [board test];
}

-(void)didLoad{
    [self setup];
}

The Board Class:

@interface Board : NSObject{
@property(nonatomic, retain) NSMutableDictionary *dict;

-(Board *)createBoard;
-(void)test;

@implementation Board
@synthesize dict;

-(Board *)createBoard{

    dict = [[NSMutableDictionary alloc]init];

    [dict setObject:@"foo1" forKey:@"1"];
    [dict setObject:@"foo2" forKey:@"2"];
    [dict setObject:@"foo3" forKey:@"3"];
    [dict setObject:@"foo4" forKey:@"4"];
    [dict setObject:@"foo5" forKey:@"5"];

    return self;
}

-(void)test{
    NSLog(@"Test return: %@", [dict objectForKey:@"4"]);
}

The following output:

2012-06-23 01:05:28.614 Game[21430:207] Test return: foo4
2012-06-23 01:05:32.539 Game[21430:207] Test return: (null)

In advance, thanks for any help!

Answer 1

@implementation Game
-(void)setup{
    board = [[[Board alloc] init] createBoard];
    [board test]; //returns right value
    [self testAgain]; //returns (null), see output below
}

The creation pattern you are using is outside every convention in Objective-C. You should either use [Board new], [[Board alloc] init|With…|] or [Board board|With…|].

-(Board *)createBoard {

    self.dict = [[NSMutableDictionary alloc]init];

    [dict setObject:@"foo1" forKey:@"1"];
    [dict setObject:@"foo2" forKey:@"2"];
    [dict setObject:@"foo3" forKey:@"3"];
    [dict setObject:@"foo4" forKey:@"4"];
    [dict setObject:@"foo5" forKey:@"5"];
}

Lets see if your code works better with the missing init reinstalled where it belongs and that little missing self. .