Question

I need to get the value of a UIImage’s image as a string.

Previously I was doing:

if(images[imageNo].image == [UIImage imageNamed:@"image1.png"])
{

But now I have a lot more conditions so I would like to use a switch, doing:

switch(images[imageNo].image)
{
    case @"image1.png":
    break;
}

Is there a way to achieve this? Thanks!

Answer 1

Both of your approaches are incorrect. The first one relies on caching (which is not documented), meanwhile the second is a syntax error – the ‘case’ keywords expect a compile-time constant expression.

As far as I know, there’s no such a method in the iOS SDK that would return an image’s filename – simply because it’s not a property of the image (what would it return for a programmatically created image?). You should instead try to operate on an NSDictionary, storing the UIImage objects associated with the filenames as keys, and comparing the keys using isEqualToString:.

So you should create your images only once, and store them in a dictionary:

// assuming `images` is an already created instance variable of your class
[images setObject:[UIImage imageNamed:@"ImgOne.png"] forKey:@"ImgOne.png"];
// and so on, with every image you need

// then once you have to check against a file name, use:
UIImage *img = [images objectForKey:@"FileName.png"];
if ([someImage isEqual:img]) {
    // you can now be sure that the image set to the object was once named "FileName"
}