Access an NSMutableArray of objects which are in another NSMutableArray (I.E. Nested Object access)

Question

I have a class (USER) which has the following properties (NSString name, NSString address, NSMutableArray tags). The tags property is an NSMutableArray of (TAG) - TAG is a class defined as (NSNumber tagId, NSString tagName).

I have tried a few different ways to access the tagName and tagId however have been unsuccessful.

Example code 1 below:

Tag *tag = [[Tag alloc] init];
for(NSInteger n = 0; n < [thisSpotTag count]; n++)
{
    NSLog(@"%@", [thisSpotTag objectAtIndex:n]);
}

Example code 2 below:

NSEnumerator *enumerator = [thisSpotTag objectEnumerator];
NSString *tname = nil;
while((tname = [enumerator nextObject]))
{
    NSLog(@"%@", tname);
}

In both examples, I get the memory address of the tag, but not the value of the tagName and tagId.

How do I access this information?

PS - I am using xCode 4.2 with ARC.

---

Update on my question below:

I'm back, and tried a few of the suggested fixes below however I still cannot get the data out of the array. Remember, I have an array of objects in which each object contains an array of objects.

I have this code for example:

NSEnumerator *enumerator = [thisUser.tags objectEnumerator];
Tag *tagObj = [[Tag alloc] init];    
while(tagObj = [enumerator nextObject])
{
    NSLog(@"enumerated tag id:%@ name:%@", tagObj.tid, tagObj.name);
}

I never make it into the while loop in the code above...

thisUser.tag is the TAG object for portion of a USER object. Perhaps typing out what the array looks like would help explain the nesting.

NSMutableArray(               "this is an NSMutableArray of USER objects"
    element 0 =>  USER Object 1
        USER.name is an NSString
        USER.address is an NSString
        USER.tag              "this is an NSMutableArray of TAG objects"
            element 0 => TAG Object 1
                TAG.tagId is an NSNumber
                TAG.tagName is an NSString
            element 1 => TAG Object 2
               ...etc...
    element 1 => USER Object 2
        ...etc...

Answer 1

You are getting object of class Tag, you need to take the object and access it's property.

Tag *tag;
NSString *tname;
while((tag = [enumerator nextObject]))
{
    tname = tag.tagName
    NSLog(@"%@", tname);
}

This code is assuming that you have declare the appropriate @property

Answer 2

Tag *tag = [[Tag alloc] init];
for(NSInteger n = 0; n < [thisSpotTag count]; n++)
{
   tag = (Tag*)[thisSpotTag objectAtIndex:n]
    NSLog(@"Tagg Name:%@",tag.tagName);

}

Answer 3

In your Tag class, the tagID and tagName should be defined as properties. So in the class header file for Tag:

@property (nonatomic, strong) NSNumber *tagID;
@property (nonatomic, strong) NSString *tagName;

and in the implementation synthesize the properties:

@synthesize tagID = _tagID;
@synthesize tageName = _tagName;

Then, whenever you have a tag object you can access the instance variables by using dot notation. For example:

Tag *exampleTag = [[Tag alloc] init];
exampleTag.tagName = @"Some name for your tag";

Now, if your objects are stored in an array you can iterate through the array and read or write from each tag by using fast enumeration. For example, assuming you have an array of Tag objects in an array called 'arrayOfTags':

for(Tag *tag in arrayOfTags) {
    tag.tagName = @"some string";
}

Answer 4

Try casting then accessing the properties:

[(Tag *)[array objectAtIndex:i] tagId];
[(Tag *)[array objectAtIndex:i] tagName];

Or, for fast enumeration (better), do

(Tag *)tag = [enumerator nextObject];
tag.tagId;
tag.tagName;

For an NSMutableArray of Users, you need to cast like this:

User *user = (User *)[array objectAtIndex:i];
Tag *tag = (Tag *)[user.tags objectAtIndex:j];

Now you can simply call properties:

tag.tagId;
tag.tagName;

Remember that whenever you are using an NSMutableArray or NSArray with custom objects, all you need to do is to tell the compiler what type the object is. Then everything will work as you expect.

Here's an example for your case, starting with NSMutableArray *usersArray of Users:

for (int i=0; i<usersArray.count; ++i) {
    User *user = (User *)[usersArray objectAtIndex:i];
    NSLog(@"Name: %@\n",user.name);
    NSLog(@"Address: %@\n",user.address);
    NSLog(@"Tags: \n");
    for (int j=0; j<[user.tags count]; ++j) {
        NSLog(@"ID: %@", (Tag *)[[user.tags objectAtIndex:j] tagID]);
        NSLog(@"Name: %@", (Tag *)[[user.tags objectAtIndex:j] tagName]);
    }
    [user release];
}