Save image that is displayed in UIImage and categorize it

Question

I want to save an image that is displayed in the UIImage . However I want to categorize it in genre for example vegetables, meat, lettuce, etc.

I cannot find a way to do that.
What is the best and easiest way to do this?

Also I want to make the user select which category he wants to save using the picker controller to save. Thank you! I really need help!!

Update 2
To check if it is saved I went further to construct a collection View controller and I get errors saying at the images part at the [arrayCollectionImages addObject:image]; Can you explain me about this last piece of code. I also have an warning at arrayCollectionImages saying local declaration of arrayColectionImages hide instance variable. –

@interface CollectionViewController (){
    NSArray *arrayCollectionImages;
}


@end

@implementation CollectionViewController

- (void)viewDidLoad {
        dispatch_queue_t searchQ = dispatch_queue_create("com.awesome", 0);
        dispatch_async(searchQ, ^{
            NSArray *arrayCollectionImages = [[NSArray alloc ]init];
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDirectory = [paths objectAtIndex:0];
            NSString *location=@"Hats";
            NSString *fPath = [documentsDirectory stringByAppendingPathComponent:location];
            NSArray *directoryContent = [[NSFileManager defaultManager] directoryContentsAtPath: fPath];
            for(NSString *str in directoryContent){
                NSString *finalFilePath = [fPath stringByAppendingPathComponent:str];
                NSData *data = [NSData dataWithContentsOfFile:finalFilePath];
                if(data)
                {   dispatch_async(dispatch_get_main_queue(),^{
                    UIImage *image = [UIImage imageWithData:data];
                });
                    [arrayCollectionImages addObject:images];
                }
            }
        });

    [super viewDidLoad];
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    CollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"ReuseID" forIndexPath:indexPath];
    [[cell collectionImageView]setImage:[UIImage imageNamed:[arrayCollectionImages objectAtindex:indexPath.item]]];
    return cell;
}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
    return [arrayCollectionImages count];
}
@end

Answer 1

Step 1:
Set up a Picker Controller.
Here is the official reference.
Here is a tutorial.

Try to set it with all the genre values you want. You will learn about its delegate method:

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component

that will return the genre selected.

Step 2:
Provide a save icon or a save button on each image. On click of that icon/button you should make your picker view appear and make user select any row and the image should be copied to a private variable or a property here, so as to refer it later in the delegate method.

Step 3: When user selects a row, this delegate method is called. Here we will create a new directory , if not already exists, according to the genre selected In UIPickerView. Then you should write your image to the path.

   - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
            NSArray  *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDirectory = [paths objectAtIndex:0];
            //fetch Category Name from the array used to fill the Picker View 
            NSString *categoryName= [array objectAtIndex:row];
            NSString *fPath = [documentsDirectory stringByAppendingPathComponent:categoryName];
            NSFileManager *fileManager=[[NSFileManager alloc]init];
            [fileManager createDirectoryAtPath:fPath withIntermediateDirectories:YES attributes:NO error:NO];

            UIImage *image= captureImage;
            NSData *data= UIImagePNGRepresentation(image);
            [data writeToFile:fPath atomically:NO];
}

To retrieve images from a particular folder in your documents directory:
Create a path to that folder first. This will depend on a particular genre. Let's say Genre1.

 // An array to save all images. You have to do this in some other way if selected images are big in size.
 // For that case I suggest retrieving of images only when you are showing them on screen. 
  NSArray *allImagesArray = [[NSArray alloc ]init];
  NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
  NSString *documentsDirectory = [paths objectAtIndex:0];
  NSString *location=@"Genre1";
  NSString *fPath = [documentsDirectory stringByAppendingPathComponent:location]; 
  NSArray *directoryContent = [[NSFileManager defaultManager] directoryContentsAtPath: fPath];
  for(NSString *str in directoryContent){
   NSString *finalFilePath = [fPath stringByAppendingPathComponent:str]; 
    NSData *data = [NSData dataWithContentsOfFile:finalFilePath];
      if(data)
      {
        UIImage *image = [UIImage imageWithData:data];
        [allImagesArray addObject:image];
      }
  }