CODEWITHSUNDEEP
objective-ccocoa-touchnsstring
hanumanDev
hanumanDev

Reputation: 6614

Inspecting the string created by stringWithFormat:

When setting the image for a button, I use stringWithFormat: like so:

 [buttonImage setImage:[ImgUtil image:[NSString stringWithFormat:@"myImage_%d.png", selectNum + 1 ]] ];

I want to inspect that string. I thought maybe I could get the name back from the button: 

 if (buttonImage.image == [UIImage imageNamed:@"myImage_2.png"]) {
        NSLog(@"the name of the buttonImage is %@", buttonImage.image);
 }

but that doesn't work. How can I look at that string?

Upvotes: 0

Views: 214

Answers (5)

WendiKidd
WendiKidd

Reputation: 4373

No, you can't.

buttonImage.image is a UIImage stored in memory inside the button.

[UIImage imageNamed:@"myImage_2.png"] creates an entirely different UIImage. Both UIImages could very well have been created from the same file--in this case, @"myImage_2.png"--but they are two separate UIImages in memory.

The == check in your line:

if(buttonImage.image == [UIImage imageNamed:@"myImage_2.png"])

Does not check if the UIImages were created from the same file; it checks if they are pointing to the same location in memory. Which they are not, because they are two separately created and stored UIImage instances.

--

So, no--you cannot do this. Something that might solve your problem another way, though, is to subclass UIButton and add a properly NSString* imageFilename. (If you're setting different images for each control state, you'd need more than one variable to store those image file names in). Then override the setImage:forControlState method of the UIButton subclass and store the filename there every time the image is changed. Then you can perform the following check:

if([imageFileName isEqualToString:[[NSString stringWithFormat:@"myImage_%d.png", selectNum + 1 ]])

And that would get you the answer you want!

Upvotes: 2

clearscreen
clearscreen

Reputation: 2027

If what you want is to "test what the "myImage_%d.png" ends up being" in the following line:

[buttonImage setImage:[ImgUtil image:[NSString stringWithFormat:@"myImage_%d.png", selectNum + 1 ]] ];

Then I would suggest that you reformat and simplify your code. It will give you the additional advantage of making it easier to read:

NSString* imageName = [NSString stringWithFormat:@"myImage_%d.png", selectNum + 1 ];
NSLog(@"imageName is %@", imageName);

[buttonImage setImage:[ImgUtil image:imageName]];

Upvotes: 2

anna
anna

Reputation: 662

selectNum stands for the selected image, right?If so, try to get selectNum when picking the picture.

Upvotes: 0

Cthutu
Cthutu

Reputation: 8907

You could use associated references to attach a string the key "name" at load time. You create the UIImage from a file, and attach the name using the objective-c associated references API: here.

You can also sub-class UIImage to store an extra name.

You can even add a category to provide an easy API.

Upvotes: 3

nhahtdh
nhahtdh

Reputation: 56809

You can store the UIImage as instance of the class, and compare it. You won't be using more memory than a pointer.

Upvotes: 1

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