Question

Say I have 5 UIImageViews, named
image1
image2
image3
image4
and image5.

And I have 5 buttons, which have their tag values set to the corresponding images that overlay them, so 1 – 5.

If button 1 is pressed, I get the tag value like so

NSNumber buttonNumber = [sender tag];

I then want to perform some methods on the corresponding image (image1). But I want to use the same method for all of the buttons.

So my question is, having retrieved the tag, how can I identify the corresponding image (with the same number after its name). The solution I have so far, which is a bit long winded, is to use a switch:

  UIImageView *image;
        switch (buttonTag) {
            case 1:
                image = imageOverButton1;
                break;
            case 2:
                image = imageOverButton2;
                break;
            default:
                break;
// etc
        }

But this doesn’t seem to be very elegant. If it were a string I could of course use

stringWithFormat:@"imageOverButton%i", buttonTag

So is there an equivalent operation for objects?

I know I could also set the button’s background image to the image I want and extract the imageData from the sender but I’d rather do it the above way for various reasons. I suppose I could also add the UIImageViews to an array and extract the relevant object by using the tag.

Thanks! 😀

Michael

Answer 1

I think you answered your own question – use an array to hold your UIImageViews and use the tag as an index into that array.

EDIT, folding in my comment: The name of your objects isn’t reified – you can’t say NSObject foo; and then later be able to reference it with some lookup using @"foo" unless you explicitly make an array mapping names to objects. See another answer I gave to a similar problem.