Re: NSMutableArray is null?
Re: NSMutableArray is null?
- Subject: Re: NSMutableArray is null?
- From: Roland King <email@hidden>
- Date: Wed, 01 Apr 2009 10:45:21 +0800
don't beat yourself up too much.
I spent 30 minutes last night staring at this line of code and trying to
figure out why it wouldn't compile. Checked headers, checked libraries,
checked the definition of the function sin(). Pulled out hair by the
handful, restarted XCode .. when it finally dawned on me I decided it
was time to go to bed ..
double sin = sin( angle );
Pierce Freeman wrote:
Ken:
Note to self, don't go writing to support boards when I am already half
asleep. ;) I realize that now, and I understand what instance variables
are, just I couldn't think of the name when I was writing my original post.
And in my instance variable programming, I forgot that you have to run this
no matter if it is an instance variable or not:
globalVariable = [[NSMutableArray alloc] init];
On 3/31/09 7:19 PM, "Ken Thomases" <email@hidden> wrote:
On Mar 31, 2009, at 9:12 PM, Pierce Freeman wrote:
Whoops, sorry I didn't put that in...
@interface Example_Class : NSObject {
IBOutlet NSTableView *tableView;
NSMutableArray *globalVariable;
}
That's not a global variable. It's an instance variable. That's a
massive conceptual error, and you should do your best to understand
why you made it before going much further. Perhaps reading Apple's
guide to Object-Oriented Programming with Objective-C would help:
http://developer.apple.com/documentation/Cocoa/Conceptual/OOP_ObjC/index.html
Next, what you showed is the declaration of the variable. The
variable is a pointer, which may point to an object. Declaring a
pointer does not allocate or initialize the object, nor make the
pointer point to the object (or anything in particular). You have to
do that separately.
Regards,
Ken
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