How to set a value for an image - image

Question

I am using a switch statement to fill imageviews with pictures at random.
Now I am trying to give the pictures a value. That way I can use that value to make comparison. Can somebody explain me how to give images a value?
I have used the following code to setup the array for the UIImages, but can't get it completely working: (.m file)
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIImage *image1 = [UIImage imageNamed:#"image-1.png"];
UIImage *image2 = [UIImage imageNamed:#"image-2.png"];
UIImage *image3 = [UIImage imageNamed:#"image-3.png"];
UIImage *image4 = [UIImage imageNamed:#"image-4.png"];
UIImage *image5 = [UIImage imageNamed:#"image-5.png"];
_imageArray = #[image1, image2, image3, image4, image5];
}
-(void)displayImageRandomlyOnView {
NSUInteger randomIndex = arc4random_uniform([_imageArray count]);
_imageToDisplay.image = [_imageArray objectAtIndex:randomIndex];
}
Have created also a button in the .h file, to call the view...but can't get the code working for the button calling the view.
If I now try to run the IS it crashes even without the button in it. Can somebody tell me what is going wrong?
The following information is in the .h file: (have left the button out)
#import <UIKit/UIKit.h>
#interface ViewController : UIViewController
#property (weak, nonatomic) IBOutlet UIImageView *imageToDisplay;
#property (strong, nonatomic) NSArray *imageArray;
That was really helpful! I have now created a button that will fill in total 10 UiImage views. 5 in the left side of the screen, UiImage view 1-5 and right side I have UiImage view 6-10. I created two separe array's to fill the right and the left side. The only thing I now want to do is to compare the UiImage view 1-5 against 6-10. If a UiImage view is filled with an image it should return value 1 and if not it should have 0. This way I can compare if the right or left side has more images filled or exactly the same. Can you point me in the right direction on how to do this? Thanks!

Answer 1

I would suggest storing the UIImages in an array, sorting them randomly, and then sequentially fill the UIImageViews with the images. This way you don't need to attach a value to the images as you know what position they are in the array from their position amongst your image views.
EDIT
You should replace the line
_imageArray = #[image1, image2, image3, image4, image5];
with
_imageArray = [[NSArray alloc] initWithObjects:image1, image2, image3, image4, image5, nil];
What you had would cause an error like this in the Xcode console:
* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]'
EDIT 26/11/13
If you have a list of images on the screen and want to check programatically if they are loaded with images, I would suggest using an array of UIImageViews instead of an array of UIImages. Then,
// Initialise the 5 UIImageViews with the UIImages that you already initialised.
UIImageView *image1 = [[UIImageView alloc] initWithImage:image1];
UIImageView *image2 = [[UIImageView alloc] initWithImage:image2];
..
..
UIImageView *image5 = [[UIImageView alloc] initWithImage:image1];
// Put all the UIImageViews in an array.
_imageArray = [[NSArray alloc] initWithObjects:image1, image2, image3, image4, image5, nil];
// Make this method to count the number of images in the given array.
- (int)numberOfImagesIn:(NSArray *)array {
int count = 0;
for (UIImageView *view in array) {
if (view.image) {
count++;
}
}
return count;
}