private string field in iOS image UIButton

Question

This is a trick I use a lot in android:

I take an image with Image Picker: camera or gallery
I put the image in an ImageView
I also put the image url in the ImageView, in the tag field
so later when I need the url of an image (to send to server), I grab it from the imageView's tag.

But tag in iOS is a bit different from android: in iOS it's just a number. So is there such a way of piggybacking on an UIButton on iOS: basically any field whatsoever that is available for storing a text and which the user cannot see?

UIButton. **Not** UIImageView – Katedral Pillon Jul 29 '14 at 00:41 — Katedral Pillon, Jul 29 '14 at 00:41

score 1 · Answer 1 · answered Jul 29 '14 at 00:14

1

Natively, there's no way to do this. However, you can use a category and store the text in an associated object:

@interface UIImageView (StringTagAdditions)
@property (nonatomic, copy) NSString *stringTag;
@end

@implementation UIImageView (StringTagAdditions)
static NSString *kStringTagKey = @"StringTagKey";

- (NSString *)stringTag {
    return objc_getAssociatedObject(self, kStringTagKey);
}

- (void)setStringTag:(NSString *)stringTag {
    objc_setAssociatedObject(self, kStringTagKey, stringTag, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
@end

More info @ http://nshipster.com/associated-objects/

answered Jul 29 '14 at 00:14

rocky

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A computer science professor said that it's not good to add category to classes I (i.e. my team) didn't create – Katedral Pillon Jul 29 '14 at 00:33
You should find out exactly why your professor thinks "it's not good". – rocky Jul 29 '14 at 01:11

score 1 · Answer 2 · edited May 23 '17 at 11:57

1

This type of thing has been asked before, but you could pull this off with a UIButton category that adds getter/setter like methods that store this value for you:

Or you could subclass UIButton and add the property you need. There are lots of options, but I'm unclear on what you mean by "the user cannot see"?

edited May 23 '17 at 11:57

Community

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answered Jul 29 '14 at 00:14

Aaron

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I remember a computer science professor saying that it's not good to add category to classes I (i.e. my team) didn't create) – Katedral Pillon Jul 29 '14 at 00:32
No sweat, not sure I agree with your professor though. I also mentioned that you could subclass `UIButton`, :-) – Aaron Jul 29 '14 at 01:40

score 1 · Accepted Answer · answered Jul 29 '14 at 00:19

I'm not aware of an analogous field on a UIImageView. Your best bet may be to subclass UIImageView to add such a property. In the .h file for the new class, do something like:

@interface SubclassedUIImageView : UIImageView

@property (strong, nonatomic, copy) NSString *url;

@end

Then assign the url value to SubclassedUIImageView in imagePickerController: didFinishPickingMediaWithInfo:. Assuming you're using Interface Builder, to use the subclassed UIImageView, you drop a UIImageView control onto the parent view, go to the Identity inspector, and change the Custom Class field to the name of your subclassed UIImageView.

I find this a wee bit of an overkill. But it's probably the quickest option if indeed there is no native way. — Katedral Pillon, Jul 29 '14 at 00:34

private string field in iOS image UIButton

3 Answers3