IPhone persist Model - iphone

Question

I would like to persist an object of a class (not just NSString´s). For instance, I have this class:
** News.h:**
#import <Foundation/Foundation.h>
#interface News : NSObject
#property (nonatomic, retain) NSString * atrib1;
#property (nonatomic, retain) NSString * atrib2;
#end
** News.m:**
#import "News.h"
#implementation News
#synthesize atrib1;
#synthesize atrib2;
#end
Should I have to use a plist to storage it? How should I do it?

Answer 1

Using NSCoding:
In News.m, I have added:
- (void) encodeWithCoder:(NSCoder *)encoder {
[encoder encodeObject:atrib1 forKey:#"key1"];
[encoder encodeObject:atrib2 forKey:#"key2"];
}
- (id)initWithCoder:(NSCoder *)decoder {
self = [super init];
atrib1 = [[decoder decodeObjectForKey:#"key1"] retain];
atrib2 = [[decoder decodeObjectForKey:#"key2"] retain];
return self;
}
-(void)dealloc{
[super dealloc];
[atrib1 release];
[atrib2 release];
}
In News.h:
#interface News : NSObject<NSCoding>{
NSCoder *coder;
}
#property (nonatomic, retain) NSString * atrib1;
#property (nonatomic, retain) NSString * atrib2;
#end
To read update and persist a new object in the plist:
- (IBAction)addANewNews:(id)sender {
//Plist File
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *plistPath = [[paths objectAtIndex:0] stringByAppendingPathComponent:#"myplist.plist"];
//Reading current news
NSData *oldNews = [NSData dataWithContentsOfFile:plistPath];
NSMutableArray *news = (NSMutableArray *)[NSKeyedUnarchiver unarchiveObjectWithData:oldNews];
if (news == nil)
news = [[NSMutableArray alloc] init];
//Adding a new news
[news addObject:aNewNews];
NSError *error;
NSData* newData = [NSKeyedArchiver archivedDataWithRootObject:news];
//persisting the updated news
BOOL success =[newData writeToFile:plistPath options:NSDataWritingAtomic error:&error];
if (!success) {
NSLog(#"Could not write file.");
}else{
NSLog(#"Success");
}
}