Using NSKeyedArchiver to store custom data model

Question

I\'m working on a rss reader. It is just a tableview and each cell shows a custom data model RSSEntry. And I have a NSMutableArray allEntries which contains all RSSEntry I got f

Answer 1

Place all the entries you want to store into an NSArray and use this code:

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:entries];

Where entries is your array of entries. Nice and easy, just one line of code.

To unarchive, just use

NSArray *entries = [NSKeyedUnarchiver unarchiveObjectWithData:data];

NSKeyedArchiver is able to archive any data structure, even a very complex one, of Objective-C objects that implement the NSCoding protocol, including nested NSArrays, NSDictionarys, and custom objects, to a file. NSKeyedUnarchiver does the reverse, taking any data produced by NSKeyedArchiver and reestablishing the original object graph that was archived. Technically, they could just be a single class, but Apple decided to separate them by functionality because this is more grammatically correct or something :)

I assume you are able to write the resulting NSData object to a file, and read it back again.

Answer 2

For iOS 12:

for archivedDataWithRootObject:

NSData *myDicData = [NSKeyedArchiver archivedDataWithRootObject:AllDataDic 
                                     requiringSecureCoding:YES error:nil];
[[NSUserDefaults standardUserDefaults] setObject:myDicData forKey:@"Yourkey"];

for unarchivedObjectOfClass:

NSData *tempData = [[NSUserDefaults standardUserDefaults] valueForKey:@"Yourkey"];
NSDictionary *myDicProfile = [NSKeyedUnarchiver unarchivedObjectOfClass:[NSDictionary class] 
                                                fromData:tempData error:nil];

Answer 3

You could store an NSDictionary as following

NSDictionary *Your_NSDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
                               @"Obj1", @"Key1",
                               @"Obj2", @"Key2", nil];
//store dictionary
NSMutableData *yourData = [[NSMutableData alloc] init];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:yourData];
[archiver encodeObject:Your_NSDictionary forKey: @"key"];
archiver finishEncoding];
[yourData writeToFile:@"FilePath" atomically:YES];
[yourData release];
[archiver release];


//Load dictionary

NSData *yourData = [[NSMutableData alloc]initWithContentsOfFile:@"FilePath"];
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:yourData];
Your_NSDictionary = [unarchiver decodeObjectForKey: @"key"];
[unarchiver finishDecoding];
[unarchiver release];
[yourData release];