Question

I want to create a class in objective-c with its methods, so that for accessing the data I don’t want to instantiate the class. how can I do it?

Answer 1

You may use singleton pattern, check this question.

Like this:

+(MySingleton *)sharedInstance {
    static dispatch_once_t pred;
    static MySingleton *shared = nil;
    dispatch_once(&pred, ^{
        shared = [[MySingleton alloc] init];
        shared.someIvar = @"blah";
    });
    return shared;
}

Or if you want to just access methods, you may use factory methods (those with +, not with -)

@interface MyClass
@property (nonatomic, assign) NSInteger value;

+ (void) factoryMethod;
- (void) instanceMethod;

...
// then in code
[MyClass factoryMethod]; // ok
[[MyClass sharedInstance] instanceMethod]; // ok
[MyClass sharedInstance].value = 5; // ok

UPDATE:

You may add a property to appDelegate

// in your app delegate.h
@property (nonatomic, retain) UIViewController* view;
// in your app delegate.m
@synthesize view;

and get appDelegate from almost any place like:

myapp_AppDelegate* appDelegate = [[UIApplication sharedApplicaton] delegate];
appDelegate.view = ...; // set that property and use it anywhere like this

Note, that you’ll need to #import your UIViewController subclass and your appDelegate.h to make autocomplete work and sometimes avoid warnings.

// someFile.m
#import "appDelegate.h"
#import "myViewController.h"
...
myapp_AppDelegate* appDelegate = [[UIApplication sharedApplicaton] delegate];
appDelegate.view.myLabel.text = @"label text";