global variable read/write access

I need 开发者_如何学Pythonto access (read/write) some variables in all of my views.

The variables will be defined in view 1, then used and set to a new value in view 2.

How can i do this?

Ya , there is much a easy way to handle this.....

You can take a Global Variable

In your Delegate.h file declare your variable:

@interface Smoke_ApplicationAppDelegate : NSObject {

UIWindow *window;
UINavigationController *navigationController;
NSString *messageString;  //This would be your String Variable
} @property(nonatomic,retain)NSString *messageString;

Secondly in Delegate.m file

@implementation Smoke_ApplicationAppDelegate

@synthesize window; @synthesize navigationController; @synthesize messageString; // 

Synthesize it over here..

This is Done .Now you can use this String Variable in All/any class you want..

To use this Global Variable.

Just import you Delegate file make the obj of it....

import "DelegateFile.h"

@implementation About

DelegateFile *appDel;

Now in Your class.m

-(void)viewDidLoad { [super viewDidLoad];

appDel=[[UIApplication sharedApplication]delegate];

}

Now you can access it anywhere in your class by this Object:

appDel.messageString

Just follow my Steps Carefully After giving so much pain to my finger, I am sure this is definitely going to help you.....

Have a easy life,

Please don't declare them as instance variables on your application delegate, it's not really good design practice for MVC.

Your best option is to create a shared data model. This can be what is called a 'singleton' class so there is only every 1 instance of it. This model class can then store any central information that is needed by various views.

Rob Napier's answer over here is a good reference as are other links from that page. In particular I'd commend Mike Ash's post here.

'Singletons' are great. They encapsulate the data in a model class where it belongs and avoid creeping global variables which make code less easy to decouple in future.