Question

I am looking for the most optimal way to store and read variables globally across all my classes. I understand I could use a ‘singleton’ however I wasn’t sure whether this was the best method for storing my variables or how to go about doing this exactly?

Answer 1

I use singletons and here is how I do it:

Create a new class, for the demonstration here we will name it MyDataModel. In MyDataModel.h do the following:

#import <Foundation/Foundation.h>

@interface MyDataModel : NSObject
{
    NSString *myStringVariable;
    NSUInteger myIntVariable;
    //add any variables you need
}

@property (nonatomic, retain) NSString *myStringVariable;
@property (nonatomic) NSUInteger myIntVariable;

+ (MyDataModel *) sharedInstance;

@end

Now in the MyDataModel.m do:

#import "MyDataModel.h"

@implementation MyDataModel

@synthesize myStringVariable, myIntVariable;

static MyDataModel *_sharedInstance;

+ (MyDataModel *) sharedInstance
{
    if(!_sharedInstance)
    {
        _sharedInstance = [[MyDataModel alloc] init];
    }
    return _sharedInstance;
}

@end

Now in any class you want to use this singleton you have to #import this class and here is how to use the variables:

[MyDataModel sharedInstance].myStringVariable = @"anyThing";
[MyDataModel sharedInstance].myIntVariable = 123;

I hope this clarifies things for you.