Saving Array to PList from downloaded content in table view on iPhone

Question

I copied these posts from a forum where I posted recently, but got no reply.

I have the base for my code all setup, it is a drill down table with navigation controller which loads data into a nsmutabledictionary from a plist with some empty values, on purpose. On command the app then downloads information which is then set, setValue, in NSMutableArray. The issue is that this NSMutableArray is 3 levels down from the root of the plist. I am looking for a way to replace the array in the plist which is loaded and saved in the appdelegate. How do I this? Help is much appreciated.

So that probably didn't make much sense. In the AppDelegate it loads a plist file into an NSMutableDictionary. The plist is like this:

Root
>Title(String)
>Rows(Array)
>>Item 1(Dictionary)
>>>Title(String)
>>>ID(String)
>>>ItemList(Array)
>>>>Item 1(Dictionary)
>>>>>Title(String)
>>>>>ID(String)
>>>>>Value(String)-----------Empty Value which is Downloaded
>>>>Item 2(Dictionary)
>>>>Item 3(Dictionary)
>>>>Item 4(Dictionary)
>>Item 2(Array)
>>Item 3(Array)
>>Item 4(Array)

The Rows array is sent to the RootViewController. When one of these items is selected from the TableView and new instance is created with the table data source set to the ItemList of that selected item. When the user presses a button it downloads the values and using [setValue: forKey:@"Value"] the values are set in the array. Here is where it gets lost. I need to now set this ItemList array back into the main Root dictionary and then that Root dictionary sent back to the AppDelegate, so that on applicationWillTerminate [self.data writeToFile:] can be called and the downloaded information does not need to be downloaded the next time.

Answer 1

I'm not totally sure I understanad what your problem is. Once you've got the new value populated into the array, you just need to use setObject:forKey: on the dictionary to replace the old array.

If you're having trouble getting a reference to the app delegate, you can use [[UIApplication sharedApplication] delegate]

if the problem is that your dictionaries and arrays are nested such that you need to change more than one object to set the value, consider using mutableCopy to produce mutable arrays and dictionaries from the plist on load. Alternatively, maybe think about using a mire-sophisticated data representation, rather than reading and writing plist format.

Answer 2

I believe I might have to use forKeyPath