Should I Add Something To The Header File? - objective-c

Question

I'm writing an app and getting this error. Not sure how I would go about fixing it. Thank you.
The error is an undeclared identifier 'collectionView'
And the header file is being imported.
Header:
#import <UIKit/UIKit.h>
NSMutableData *content;
#interface AMCollectionViewController : UICollectionViewController
#property (weak, nonatomic) IBOutlet UIBarButtonItem *tagButton;
- (IBAction)tagButtonTouched:(id)sender;
#end
Implementation where error is occurring
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath*)indexPath
{
if(shareEnabled){
//determine the selected items by using the indexPath
NSString *selectedPhotos = [tagImages[indexPath.section] objectAtIndex:indexPath];
//add selected image into the array
[selectedPhotos addObject:selectedPhotos];
}
}
Thanks a lot guys
I use collectionView multiple times in the same .m file
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return 50;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
static NSString *identifier =#"Cell";
AMCollectionViewCell *cell = (AMCollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
int imageNumber = indexPath.row % 10;
cell.imageView.image = [UIImage imageNamed:[NSString stringWithFormat:#"imageicon%d.jpg",imageNumber]];
cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"imageBorder.jpg"]];
return cell;
}

Answer 1

I don't know about that error, but
Your second reference to indexPath on this line can't be right:
NSString *selectedPhotos = [tagImages[indexPath.section] objectAtIndex:indexPath];
The objectAtIndex parameter needs an integer. You probably meant:
NSString *selectedPhotos = [tagImages[indexPath.section] objectAtIndex:indexPath.item];
or, to be more consistent (either use objectAtIndex or use the [] syntax, but using both is a little curious):
NSString *selectedPhotos = tagImages[indexPath.section][indexPath.item];
You haven't shown the declaration of tagImages, nor it's initialization, but I assume it is tagImages an array of an array of strings? If so, the above correction should fix it. If not, you should tell us how tabImages is populated/structured.
If selectedPhotos is a NSString, the use of the addObject method won't possibly work. The addObject method is a NSMutableArray method, not a NSString method.