Make a Custom Class Serializable in Objective-c/iPhone?

Question

How can I make my own custom class serializable? I specifically want to write it to a file on iPhone, just plist and thee class is just a simple instance class, just NSStrings and maybe a NSUrl.

Answer 1

You'll want to implement the NSCoding protocol. Implement initWithCoder: and encodeWithCoder: and your custom class will work with NSKeyedArchiver and NSKeyedUnarchiver.

Your initWithCoder: should look like this:

- (id)initWithCoder:(NSCoder *)aDecoder
{
   if(self = [super init]) // this needs to be [super initWithCoder:aDecoder] if the superclass implements NSCoding
   {
      aString = [[aDecoder decodeObjectForKey:@"aString"] retain];
      anotherString = [[aDecoder decodeObjectForKey:@"anotherString"] retain];
   }
   return self;
}

and encodeWithCoder:

- (void)encodeWithCoder:(NSCoder *)encoder
{
   // add [super encodeWithCoder:encoder] if the superclass implements NSCoding
   [encoder encodeObject:aString forKey:@"aString"];
   [encoder encodeObject:anotherString forKey:@"anotherString"];
}