Iterating an NSMutableDictionary with UIImage not working - ios

Question

I am trying to add Images fetched from an external service to an NSMutableDictionary and seeing weird results. This is what I am doing:
- (void)fetchImages{
//Fetch Item Brand Images
//self.itemBrands is an NSArray of NSDictionaries
for (NSDictionary *itemBrand in self.itemBrands){
NSString *currentItemId = [itemBrand objectForKey:#"ITEM_ID"];
//Valid Item Id. This Log message is displayed
NSLog(#"Current Item Id: %#",currentItemId);
NSString *currentItemImageUrl = [[IMAGE_URL stringByAppendingString:currentItemId] stringByAppendingString:#".png"];
//Image URL is valid. This log message is displayed
NSLog(#"Current Image URL: %#",currentItemImageUrl);
NSURL *url = [NSURL URLWithString:currentItemImageUrl];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:data];
if (image == nil){
//This log message is displayed when image is not present
NSLog(#"Image not Present 1");
}else{
//This log message is displayed when image is present
NSLog(#"Image Present 1");
[self.itemBrandImages setObject:image forKey:currentItemId];
}
}
//This for loop is not being executed at all. No log messages displayed.
for(id key in self.itemBrandImages){
NSLog(#"Current Item Id2: %#",key);
if ([self.itemBrandImages objectForKey:key] == nil){
NSLog(#"Image Not Present 2");
}else{
NSLog(#"Image Present 2");
}
}
}
The 2nd for loop where I am iterating over self.itemBrandImages is not being executed at all. None of the log messages inside are being displayed.
I tried the following before posting my issue here:
1) Researched similar problems in stack overflow and incorporated suggestion from one of them. The suggestion was "Perform an alloc init of the NSMUtableDictionary" in the init method of the .m file. This didn't help either.
2) To isolate the issue, I even tried adding a simple string to the NSMUtableDictionary instead of the image but even that does not seem to retained.
I am really confused as as to what I am missing or doing wrong here. Inputs are really appreciated.
Thanks,
Mike G

Answer 1

Perhaps:
for(NSString *key in [self.itemBrandImages allKeys])

Answer 2

I did an alloc init of the NSMutableDictianary right in my fetchImages method and it worked! Not sure why the alloc init in the init method did not work.
So here are my takeaways from this issue:
1) If you have an Array or dictionary #property that you are just getting and setting and not really adding or deleting objects to, then you don't need to explicitly alloc init them.
2) If you have an Array or dictionary #property that you are adding or deleting objects to ,you need to explicitly alloc init them.
Are my above statements true? Would love to hear your inputs on this.
Thanks,
Mike
New code:
- (void)fetchImages{
//Fetch Item Brand Images
self.itemBrandImages = [[NSMutableDictionary alloc] init];
for (NSDictionary *itemBrand in self.itemBrands){
NSString *currentItemId = [itemBrand objectForKey:#"ITEM_ID"];
NSLog(#"Current Item Id in ItemList: %#",currentItemId);
NSString *currentItemImageUrl = [[#"http://anythingtogo.freeiz.com/images/"stringByAppendingString:currentItemId] stringByAppendingString:#".png"];
NSLog(#"Current Image URL in ItemList: %#",currentItemImageUrl);
NSURL *url = [NSURL URLWithString:currentItemImageUrl];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:data];
if (image == nil){
NSLog(#"Image not Present 1");
}else{
NSLog(#"Image Present 1");
[self.itemBrandImages setObject:#"Test" forKey:currentItemId];
}
}