Objective-C problems - Printable Version

Objective-C problems - Printable Version

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Objective-C problems - TimMcD - Apr 24, 2009 08:36 AM

I'm working on an Interactive Fiction game, hopefully to become something like the old Wizardry Gold, as a first project. I'm getting some wierd (atleast to me) errors tho.

Code:

- (IBAction)createNorth:(id)sender {

    IFRoom* centerRoom = [IFRoom init];

    IFRoom* northernRoom = [IFRoom init];

    centerRoom.northRoom = northernRoom;

    northernRoom.southRoom = centerRoom;

    centerRoom.roomName = @"The Central Room";

    northernRoom.roomName = @"The Northern Room";

    currentRoom = centerRoom;

}

That's the button that causes the problem

vvv IFRoom.h vvv

Code:

#import <Cocoa/Cocoa.h>

@interface IFRoom : NSObject {

    NSString* roomName;

    NSString* description;

    IFRoom* westRoom;

    IFRoom* eastRoom;

    IFRoom* northRoom;

    IFRoom* southRoom;

}

@property (retain) NSString* roomName;

@property (retain) NSString* description;

@property (retain) IFRoom* westRoom;

@property (retain) IFRoom* eastRoom;

@property (retain) IFRoom* northRoom;

@property (retain) IFRoom* southRoom;

@end

And now IFRoom.m vvv

Code:

#import "IFRoom.h"

@implementation IFRoom

@synthesize roomName;

@synthesize description;

@synthesize westRoom;

@synthesize eastRoom;

@synthesize northRoom;

@synthesize southRoom;

- (id) init {

    if ( self = [super init] ) {

        self.roomName = @"Generic Room";

        self.description = @"This is a generic room.";

    }

    return self;

}

@end

The error doesn't stop the app, it just keeps the createNorth button from working properly. I still get the 'You walk north/east/west/south.' fine, but not the other parts.

I get it two errors at a time (two errors per click):
2009-04-24 09:21:47.251 graphicalIF[12764:10b] *** +[IFRoom setNorthRoom:]: unrecognized selector sent to class 0x4064
2009-04-24 09:21:47.252 graphicalIF[12764:10b] *** +[IFRoom setNorthRoom:]: unrecognized selector sent to class 0x4064

with some rudimentary tests I've found the problem is in the button createNorth, on the line centerRoom.northRoom = northernRoom;
If I comment that out, I get the same sort of error for the x.southRoom = x;

Any help?

Objective-C problems - FlamingHairball - Apr 24, 2009 09:02 AM

TimMcD Wrote:

Code:

- (IBAction)createNorth:(id)sender { IFRoom* centerRoom = [IFRoom init]; IFRoom* northernRoom = [IFRoom init]; centerRoom.northRoom = northernRoom; northernRoom.southRoom = centerRoom; centerRoom.roomName = @"The Central Room"; northernRoom.roomName = @"The Northern Room"; currentRoom = centerRoom; }

That's the button that causes the problem

vvv IFRoom.h vvv

Code:

#import <Cocoa/Cocoa.h> @interface IFRoom : NSObject { NSString* roomName; NSString* description; IFRoom* westRoom; IFRoom* eastRoom; IFRoom* northRoom; IFRoom* southRoom; } @property (retain) NSString* roomName; @property (retain) NSString* description; @property (retain) IFRoom* westRoom; @property (retain) IFRoom* eastRoom; @property (retain) IFRoom* northRoom; @property (retain) IFRoom* southRoom; @end

The error doesn't stop the app, it just keeps the createNorth button from working properly. I still get the 'You walk north/east/west/south.' fine, but not the other parts.

I get it two errors at a time (two errors per click):
2009-04-24 09:21:47.251 graphicalIF[12764:10b] *** +[IFRoom setNorthRoom:]: unrecognized selector sent to class 0x4064
2009-04-24 09:21:47.252 graphicalIF[12764:10b] *** +[IFRoom setNorthRoom:]: unrecognized selector sent to class 0x4064

with some rudimentary tests I've found the problem is in the button createNorth, on the line centerRoom.northRoom = northernRoom;
If I comment that out, I get the same sort of error for the x.southRoom = x;

Any help?

Basically, IFRoom is receiving a message(setNorthRoom: in this case) that it doesn't recognize.

Firstly, I would suggest adding the readwrite tag to your @property - I think it's the default, but you may as well add it.

Secondly, I believe createNorth: should be changed to this:

Code:

- (IBAction)createNorth:(id)sender {

    IFRoom* centerRoom = [[IFRoom alloc] init];

    IFRoom* northernRoom = [[IFRoom alloc] init];

    centerRoom.northRoom = northernRoom;

    northernRoom.southRoom = centerRoom;

    centerRoom.roomName = @"The Central Room";

    northernRoom.roomName = @"The Northern Room";

    currentRoom = centerRoom;

}

If I am not mistaken, you are calling the instance method -init on the IFRoom class. What you need to do is call +alloc, a global class method that returns an allocated instance, and then call the -init instance method.

It is very important to keep your class methods (+) separate from your instance methods(-).

Objective-C problems - TimMcD - Apr 24, 2009 01:46 PM

Heh, I was thinking that since I was on Leopard (Y'know, nifty Garbage collection

, that I didn't have to alloc. Thanks!

Objective-C problems - Oddity007 - Apr 24, 2009 02:23 PM

Garbage Collection means not having to deallocate memory manually, you still have to alloc in order for GC to be relevant.