CODEWITHSUNDEEP
iosnsdictionarynsmutabledictionary
Ricky Park
Ricky Park

Reputation: 256

setObject:forKey: of NSMutableDictionary overwrites all data in dictionary

for ( int cnt = 0 ; cnt < nPeople ; cnt++ )
{
    ABRecordRef ref = CFArrayGetValueAtIndex(allPeople, cnt);

    NSString    *firstName  = (NSString *)ABRecordCopyValue(ref, kABPersonFirstNameProperty);
    NSString    *lastName   = (NSString *)ABRecordCopyValue(ref, kABPersonLastNameProperty);
    NSString    *fullName;   

    /* skipped code at here : code to merge firstName and lastName to fullName. In my country, many of us don't separate first name and last name */

    // tempKeyString : NSString variable that has key of fullNameArray value for nameDictionary.
    // fullNameArray : to keep some fullName variables for tempKeyString.
    if (!tempKeyString) // there's no tempKeyString, a.k.a. it's the first fullName.
    {
        // it's not important to know about GetUTF8String:fullName. It's for my own language.
        tempKeyString = [self GetUTF8String:fullName];
        [fullNameArray addObject:fullName];
    }
    else
    {
        if ([tempKeyString characterAtIndex:0] == [[self GetUTF8String:fullName] characterAtIndex:0]) // if fullName has the same tempKey with fullNameArray.
        {
            [fullNameArray addObject:fullName];
        }
        else // if fullName has different tempKey with fullNameArray.
        {
            //tempKey : key data for fullNameArray
            NSString    *tempKey    = [tempKeyString substringToIndex:1];
            // tempDict : to keep the deep copy of nameDictionary before adding new key.
            NSDictionary *tempDict   = [nameDictionary mutableDeepCopy];
            // add new key (tempKey) with new value (fullNameArray)
            // PROBLEM : ALL values (including previous values) in dictionary(nameDictionary) are overwritten to a new value(fullNameArray).
            [nameDictionary setObject:fullNameArray forKey:tempKey];

            //empties fullNameArray so that it can get the new fullName of the new tempKey.
            [fullNameArray removeAllObjects];
            //refresh tempKeyString, and add the new fullName.
            tempKeyString = [self GetUTF8String:fullName];
            [fullNameArray addObject:fullName];
            ...
        }
    }
}

I'm trying to make a NSMutableDictionary object from the contacts of my iPhone. Why I make a NSMutableDictionary typed object is that I need indexes for contacts, and it doesn't look easy to make indexes from ABAddressRef typed object directly. I also need to make searching function..

There was no problem when I just coded, but after debugging the only problem makes me crazy. After I apply the array named fullNameArray with the key named tempKey to the namedDictionary, I can find the nameDictionary has all values with them of fullNameArray. All previous data were overwritten! I tried to make a deep copied version of previous nameDictionary before applying fullNameArray and copy it to the newer nameDictionary. However, when I checked the breakpoint at the third line, I can't find the previous data at the tempDict.

I added more codes and comments. It might help more than my explanation.. any questions are pleased!

I tried to find the reason from here - StackOverflow -, and other webpages all the night, but I couldn't find any similar problems.. please help me! Thank you so much in advance!!

Upvotes: 2

Views: 3340

Answers (1)

X Slash
X Slash

Reputation: 4131

The reason why it get emptied is because 

[nameDictionary setObject:fullNameArray forKey:tempKey];

here, you set up your dictionary with the object "fullNameArray", then 

[fullNameArray removeAllObjects];

remove all the values inside this array, effectively, removing your object in the "nameDictionary", they are the same object, it's not a deep copy of fullNameArray that you store inside your dictionary. Why did you need to store anything into your array anyway? You're only storing 1 value.

[nameDictionary setObject:fullName forKey:tempKey];

will do what you need. Sorry if I mistaken your question, it's quite hard to understand

Upvotes: 2

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