CODEWITHSUNDEEP
iphonensuserdefaultsnsmutabledictionary
Ratan
Ratan

Reputation: 1757

Unable to update NSMutableDictionary initialized with the NSUserDefauts value

I used NSUserDefaults to save NSMutableDictionary. But when I am retrieving the value from the NSUserDefaults, I am unbale to modify/update the values of the NSMutableDictionary into which I am saving the values.

Need some suggestion on how to do so?

Upvotes: 0

Views: 350

Answers (2)

Elias
Elias

Reputation: 519

You can also save to a plist.

This is how you write to a plist:

NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * docDirectory = [paths objectAtIndex:0];
NSString * dataFilePath = [docDirectory stringByAppendingPathComponent:@"YourFile.dat"]

NSMutableDictionary * newLocalPlist = [[NSMutableDictionary alloc] init];

// add your prefs here

[newLocalPlist writeToFile:dataFilePath atomically:YES];
[newLocalPlist release];

And this is how you read from a plist:

NSArray * paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString * docDirectory = [paths objectAtIndex:0];
NSString * dataFilePath = [docDirectory stringByAppendingPathComponent:@"YourFile.dat"]
NSMutableDictionary * lastLocalPlist = [[[NSMutableDictionary alloc] initWithContentsOfFile:dataFilePath] autorelease];

Upvotes: 0

DarkDust
DarkDust

Reputation: 92316

You always get non-mutable instances of NSDictionary from NSUserDefaults. To make them mutable, you need to do something like this:

dict = [[NSUserDefaults standardUserDefaults] objectForKey:@"myKey"];
myMutableDict = [dict mutableCopy];
// Note that the retain count is +1, so you will need to
// release or autorelease myMutableDict later on.

Upvotes: 1

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