Adding NSMutableArray to NSMutableDictionary and the arrays are null? - iphone

Question

I've got a simple object "post" that has two NSMutableArrays as properties. One is for "image" objects and the other is for "video" objects. At some point in the lifecycle of "post", I ask it for a dictionary representation of itself.
NSMutableDictionary *postDict = [post getDictionary];
-(NSMutableDictionary *)getDictionary{
NSMutableArray *imgDictArry = [NSMutableArray arrayWithObjects:nil];
NSMutableArray *movDictArry = [NSMutableArray arrayWithObjects:nil];
for (int i = 0; i<self.images.count; i++) {
NSMutableDictionary *imgDict = [[self.images objectAtIndex:i] getDictionary];
[imgDictArry addObject:imgDict];
}
for (int i = 0; i<self.videos.count; i++) {
NSMutableDictionary *movDict = [[self.videos objectAtIndex:i] getDictionary];
[movDictArry addObject:movDict];
}
NSMutableDictionary *postDict = [NSMutableDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:self.friendsOnly], #"IsFriendsOnly",
self.message, #"Message",
self.shortText, #"ShortText",
self.authorId, #"AuthorId",
self.recipientId, #"RecipientId",
self.language, #"Language",
self.lat, #"Lat",
self.lng, #"Lng",
imgDictArry, #"Images",
movDictArry, #"Videos",
nil];
return postDict;
}
As you can see, the "image" and "video" objects have their own methods for describing themselves as NSMutableDictionary objects.
-(NSMutableDictionary *)getDictionary{
return [NSMutableDictionary dictionaryWithObjectsAndKeys:
self.nativeURL, #"NativeURL",
self.previewURL, #"PreviewURL",
self.smallURL, #"SmallURL",
self.thumbURL, #"ThumbURL",
self.imageId, #"ImageId",
self.width, #"Width",
self.height, #"Height",
nil];
}
I'm not getting any errors but my imgDictArry and movDictArry objects are turning out to be NULL after I've set them on the postDict object. If I log them to the console just before this moment, I can see the dictionary data. But the other classes requesting this object is getting null for those properties.

Answer 1

Perhaps one of your functions such as self.shortText (or self.lat...) is returning nil, in which case dictionaryWithObjectsAndKeys isn't what you expect it to be: it's truncated to the first function that returns nil...

Answer 2

I changed the postDict creation to this...
NSMutableDictionary *postDict = [NSMutableDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool:self.friendsOnly], #"IsFriendsOnly",
self.message, #"Message",
self.shortText, #"ShortText",
self.authorId, #"AuthorId",
self.recipientId, #"RecipientId",
self.language, #"Language",
self.lat, #"Lat",
self.lng, #"Lng",
nil];
[postDict setObject:imgDictArry forKey:#"Images"];
[postDict setObject:movDictArry forKey:#"Videos"];
and it's fixed. But I don't know why.