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PORetrieve a nested NSDictionary from property list
 

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    <p>I want to save data in a property list in one view and retrieve it in another view. The structure of the data that I'm saving looks like this:</p> <p>Key: (NSString) Value (NSDictionary)</p> <p>The <code>NSDictionary</code> just contains strings for both keys and values. Whenever a button is pressed, I fire this method to do the saving:</p> <pre><code>- (IBAction)saveRSSItem:(id)sender { NSMutableDictionary *dictionary; if ([[NSFileManager defaultManager] fileExistsAtPath:[self dataFilePath]]){ dictionary = [[NSMutableDictionary alloc] initWithContentsOfFile:[self dataFilePath]]; } else { dictionary = [[NSMutableDictionary alloc] init]; } //Create Dictionary to store RSSItem information NSMutableDictionary *RSSdictionary = [[NSMutableDictionary alloc] init]; if (self.selectedItem.title) [RSSdictionary setValue:@"title" forKey:self.selectedItem.title]; if (self.selectedItem.summary) [RSSdictionary setValue:@"summary" forKey:self.selectedItem.summary]; if (self.selectedItem.author) [RSSdictionary setValue:@"author" forKey:self.selectedItem.author]; if (self.selectedItem.date) [RSSdictionary setValue:@"date" forKey:self.selectedItem.date]; if (self.selectedItem.content) [RSSdictionary setValue:@"content" forKey:self.selectedItem.content]; //Add saved RSSItem to dictionary [dictionary setValue:RSSdictionary forKey:self.selectedItem.title]; //Overwrite the updated dictionary in the property list NSURL *url = [[NSURL alloc] initFileURLWithPath:[self dataFilePath]]; [dictionary writeToURL:url atomically:YES]; } </code></pre> <p>When I'm trying to retrieve the data I do something like this:</p> <pre><code>NSDictionary *savedRSSItemsDictionary = [NSDictionary dictionaryWithContentsOfFile:[self propertyListFilePath]]; NSDictionary *RSSDictionary = [savedRSSItemsDictionary objectForKey:[savedRSSItemsArray objectAtIndex:indexPath.row]]; </code></pre> <p>The first line retrieves the root dictionary. The second line retrieves a the value of the first row in the property list (which is an <code>NSDictionary</code>).</p> <p>However, I can't use the method valueForKey: on <code>RSSDictionary</code>. It seems like its not an <code>NSDictionary</code>? Any ideas why I can't retrieve an <code>NSDictionary</code> when it is in the value field of a property list? Do I need to use <code>NSPropertySerialization</code>?</p>
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    1. USAtulkumar V. Jain
    1. USPietro Rea
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    1. COSorry for the weird indentations. This is my first post :)
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      1. USPietro Rea
    2. CO(a) I suspect you are confusing value & key in your first code fragment, by the values you are passing it looks like you have them the wrong way around. (b) as you provide no clue as to what is in `savedRSSItemsArray` and `indexPath.row` it will be hard for anyone to help with your second code fragment. Have you run your code in the debugger and looked at what `RSSDictionary` gets set to? If it not what you expect work backwards looking at the other variables.
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    3. COThanks for looking at my code. I am mistaking values and keys in the function call. That will most likely solve everything :)
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