Store temporary data in iOS

Question

I want to store data in iOS for globally, like session data in web. What is the best approach other than sqlite?

Answer 1

Use NSUserDefaults.
NSUserDefaults is great for saving samm data like scores, login information, program state. You dont require database knowledge and its easy to learn and use.

Here is the documentation:
http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSUserDefaults_Class/Reference/Reference.html

Here is a good tutorial:
http://www.icodeblog.com/2008/10/03/iphone-programming-tutorial-savingretrieving-data-using-nsuserdefaults/

Edit: Although, based on your comment it seems that you just want to pass data between ViewControllers. One way :

Lets suppose you want to pass NSString myString from ViewControllerA to ViewControllerB. Then create a property like this in ViewControllerB.

@property (strong, nonatomic) NSString *passedString;// strong if you are using RC, ow retain

In ViewControllerA.m , when you are allocating, initiating ViewControllerB, then

ViewControllerB *viewControllerB = [[ViewControllerB alloc]init];
viewControllerB.passedString = myString;

Another Way: (more of a global variable type way)

You can declare a property in AppDelegate.h

 @property (strong, nonatomic) NSString *passedString;

In ViewControllerB, you can create AppDelgate object and access the property:

AppDelegate *app = [[UIApplication sharedApplication]delegate];
NSString *passedString = app.passedString;

Answer 2

You can write basic types like NSNumber, NSString, NSArray, NSDictionary, etc directly into the NSUserDefaults. These will be automatically saved/loaded between app sessions.

NSString* myData = @"someValue";
[[NSUserDefaults standardUserDefaults] setObject:myData forKey:@"myData"];

For more complex data types you can take advantage of NSCoder and the NSCoding protocol to easily make your classes serializable.

The code in the answer here may be helpful. Save own Class with NSCoder

Answer 3

You can use NSUserDefaults for that.

For saving data you can use this code

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject:@"Dilip" forKey:@"firstName"];
    [defaults setObject:@"Manek" forKey:@"lastname"];
    [defaults setInteger:24 forKey:@"age"];
    [defaults synchronize];

And for retrieving data use this code

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *firstName = [defaults objectForKey:@"firstName"];
    NSString *lastName = [defaults objectForKey:@"lastname"];
    int age = [defaults integerForKey:@"age"];
    NSString *ageString = [NSString stringWithFormat:@"%i",age];

You can also store NSDictionary, NSArray, or NSData as object in NSUserDefault.For more information take a look at this tutorial.

another way to pass data Between viewController is like this.

Suppose we have Two ViewController

-FirstViewController

-SecondViewController

Now if i want to pass a string from First to second ViewController thanfirst create Property of that string in secondViewcontroller

#import <UIKit/UIKit.h>

@interface SecondViewcontroller : UIViewController
@property (strong, nonatomic) NSString *strFromFirst;
@end

Synthesize it in .m file. after that in firstViewController when you push view controller Send string to second Viewcontroller

SecondViewcontroller * vc = [[SecondViewcontroller alloc] initWithNibName:@"SecondViewcontroller" bundle:nil];

    // Pass the selected object to the SecondViewcontroller.
    fraudluntReportViewController.strFromFirst = @"Dilip";

    [self.navigationController pushViewController:vc animated:YES];

This will send the string from FirstViewController to SecondViewController.

Answer 4

You need to use NSUSERDefault its very easy to handle.

You can save NSString,NSDictionaray ,NSnumber in NSUserDefault like this..

// Store Array values

NSMutableArray *array = [NSMutableArray array];
[[NSUserDefaults standardUserDefaults] setObject:array forKey:@"array"];

// Stroe String to nsuserDefault

 NSString *str=@"ABC";
 [[NSUserDefaults standardUserDefaults] setObject:str forKey:@"value"];

Answer 5

If you have limited data to store feel free to use NSUserDefaults. Apple Reference for NSUserDefaults

for example you need to store some string(say name) in to user defaults.

NSString *name = "Your Name";
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:name forKey:@"name"];
[defaults synchronize];

IMPORTANT here is, once you done with setObject for key, you have to call synchronize method so that these changes get stored in User Defaults

for accessing the same firstName string

NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
[defaults objectForKey:@"name"];