从子类向UIView添加UIImageView

Question

I created a custom class called Slot and it is a subclass of UIView. In the slot class, the following function is called:

- (NSString*)assignItem:(Item*)item {
   NSString *message;

   if (item.slotSize + currentCapacity > slotSize) {
      message = @"Sorry this item will not fit.";
   } else {
      //uiimageview stuff
      UIImage *image = [[UIImage alloc] initWithContentsOfFile:item.imageName];
      UIImageView *iv = [[UIImageView alloc] initWithImage:image];

      [self addSubview:iv]; 

      [items addObject:item];
      currentCapacity = currentCapacity + item.slotSize;

      message = @"Success";
   }

   NSLog(@"%@",message);
   return message;
}

What happens is an Item (another custom class, subclass of NSObject) is passed to the Slot a UIImageView is created from the item from a string to an image in the bundle and it is added to the subview. However, the image isn't showing. The Success message is showing so I know its getting in there. Is there another way to add a subview from the subclass or am I just doing it all wrong?

Answer 1

UIImage *image = [[UIImage alloc] initWithContentsOfFile:item.imageName];

This is not the correct way to instantiate an image that you have in the bundle. You can either use imageNamed: like this,

UIImage *image = [UIImage imageNamed:item.imageName];

Or, you can get the image with initWithContentsOfFile like this,

NSString *imagePath = [[NSBundle mainBundle] pathForResource:item.imageName ofType:@"JPG"]; // replace JPG with whatever is appropriate for your image.
UIImage *image = [UIImage imageWithContentsOfFile:imagePath];

imageNamed: will cache the images, the other way doesn't.