Determine Button Background Image - Objective-C (Xcode)

Question

I have a view controller with different buttons with background images assigned. My header file looks as follows:

@interface ImageSelect : UIViewController

- (IBAction)ImageButton:(id)sender;

- (IBAction)Done:(id)sender;

@property(nonatomic, readonly, retain) UIImage *currentImage;

@end

And the section of my main file that contains the button method looks like:

- (IBAction)ImageButton:(id)sender {

    if ([@"railway-336702_1280.jpg" isEqual:self.currentImage]) {

        img = @"railway-336702_1280.jpg";
        NSLog(@"Test");
    }

}

I am wanting to save the image name to a NSString called img. Currently, the code runs but doesn't actually perform the save to img.

Answer 1

A simpler way would be: if you simply wanted to check whether the UIButton contains that image that you set, you could simply use the tag property:

Let say you set its image with an image named: railway-336702_1280.jpg

Set the tag with something simpler like "1280".

Then check this tag against an Integer. And should you change the image again, change the tag correspondingly.

if (((UIButton*)sender).tag == 1280) 
{
    // Do stuff
}

Answer 2

Once a UIImage is created it loses all connection to the file it was loaded from. You cannot determine at runtime what the background image is.

If you need to get the name at runtime, subclass UIButton and then create a property called imageName and set it using the User Defined Runtime Attributes through Interface Builder.

Example:

In ImageSelectButton.m:

@interface ImageSelectButton ()

@property(nonatomic, retain) NSString *imageName;

@end

In ImageSelect.m:

@interface ImageSelect

...

- (IBAction)ImageButton:(ImageSelectButton*)sender {
    if ([sender.imageName isEqualToString:@"railway-336702_1280.jpg"]) {
        // Do stuff
    }
}
...

In Interface Builder when selecting your UIButton set the Custom Class and runtime attribute: