How to define a global variable that can be accessed anywhere in my application? [duplicate]

Question

Possible Duplicate:
Global int variable objective c

I would like to create a global variable. I want to access to this variable anywhere.

The Java equivalent:

static var score:int = 0; 

For example if I define a global variables into the Game class. How to access to this global variable?

Game.score ? 

Answer 1

If you are having multiple views in your application, and in that case you want to have a variable accessible to every view, you should always create a Model/Data class and define the variable in it. Something like this :

Objective-C :

//DataClass.h       @interface DataClass : NSObject {          NSString *str; }  @property(nonatomic,retain)NSString *str;     +(DataClass*)getInstance;     @end     //DataClass.m     @implementation DataClass     @synthesize str;  static DataClass *instance = nil;  +(DataClass *)getInstance {         @synchronized(self)         {             if(instance==nil)             {                 instance= [DataClass new];             }         }         return instance;     }     

Now in your view controller you need to call this method as :

DataClass *obj=[DataClass getInstance];   obj.str= @"I am Global variable";   

This variable will be accessible to every view controller. You just have to create an instance of Data class.

Swift :

class DataClass {      private var str: String!      class var sharedManager: DataClass {         struct Static {             static let instance = DataClass()         }         return Static.instance     } } 

Usage : DataClass.sharedManager.str

Using dispatch_once

class DataClass {      private var str: String!      class var sharedInstance: DataClass {         struct Static {             static var onceToken: dispatch_once_t = 0             static var instance: DataClass? = nil         }         dispatch_once(&Static.onceToken) {             Static.instance = DataClass()         }         return Static.instance!     } }   

Usage : DataClass.sharedManager.str