What will be best approach to declare global variables in iphone sdk?

Question

I am new in iphone, i just develop two little app, and in these app when i required project level global variables i used to declare in app delegate, but i read in somewhere that this is not best approach, so can someone tell me what will be best approach to declare project level global variables?

Answer 1

Well it really depends on the NUMBER of variables that you need to access. If there are a lot of variables that you need to access from anywhere within your application I'd suggest making a singleton. How to make a singleton

Here is an example on how it works made by Sachin Shanbhag

@implementation MySingleton
static MySingleton* _sharedMySingleton = nil;

+(MySingleton*)sharedMySingleton
{
     @synchronized([MySingleton class])
     {
     if (!_sharedMySingleton)
        [[self alloc] init];

      return _sharedMySingleton;
     }

return nil;
}

Answer 2

There are a many different approaches to do this:

1. Declare Variable in .h, like "myView.h" file and access it by importing this .h file (by #import "myView.h" file)

2. Declare Variable as extern in .h, like "myView.h" file as extern NSArray *myGlobalArray; Then in the AppDelegate file, allocate & initialize variable:

   myGlobalArray = [[NSArray alloc] init];

3. Then just #import "myView.h" where you need this variable.

   I thin this would help you a little bit.

Answer 3

Its either u use the word extern in the header file

extern NSString* yourVar;

or u can declare it in your app delegate as u mentioned..