NSObject+NSCoding and Archiver

build by Kingiol

Mike Mayo Rackspace Mobile Apps mike@overhrd.com twitter: @greenisus

These are some simple classes to make object persistence with NSCoding easier. This code was extracted from the Rackspace Cloud / OpenStack iOS app at http://launchpad.net/openstack-ios

Installation

CocoaPods

NSObject-NSCoding is easiest to install using CocoaPods. Simply add this line to your Podfile

pod 'NSObject-NSCoding'

and run pod install

Static

If you prefer not to use CocoaPods, simply drag Archiver.h, Archiver.m, NSObject+NSCoding.h, and NSObject+NSCoding.m into your project.

Then, right click Frameworks in Groups & Files and choose Add -> Existing Frameworks... and choose libobjc.A.dylib.

Usage

Archiver

This class will read and write objects that conform to the NSCoding protocol to disk.

SomeClass *myObject = [[[SomeClass alloc] init] autorelease];
myObject.someProperty = @"Hello world";

[Archiver persist:myObject key:@"myObject"];

// later on somewhere else...

SomeClass *myObject = [Archiver retrieve:@"myObject"];

NSObject+NSCoding

This category simplifies implementing NSCoding by iterating over the properties of your class and encoding/decoding them for you. It persists primitives (such as ints and floats) as well as any objects that conform to NSCoding.

In your class header, conform to NSCoding:

@interface Model : NSObject <NSCoding>

In your class implementation, call the automatic methods:

- (void)encodeWithCoder:(NSCoder *)coder {
   [self autoEncodeWithCoder:coder];
}

- (id)initWithCoder:(NSCoder *)coder {
    if (self = [super init]) {
        [self autoDecode:coder];
    }
    return self;
}

License

NSObject+NSCoding is released under the MIT license. A full description of that license is available in the LICENSE file.