Question

I’ve got this code trying to run a simple set of images in a cycle. All I have in the app is one UIImageView declared in my View Controller’s .h file:

@property (strong, nonatomic) IBOutlet UIImageView *imageDisplay;

And the following in my .m file’s viewDidLoad method:

NSMutableArray *imageView = [[NSMutableArray alloc] init];
[imageView addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"EyeAnim1.png"]]];
[imageView addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"EyeAnim2.png"]]];
[imageView addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"EyeAnim3.png"]]];
[imageView addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"EyeAnim4.png"]]];
[imageView addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"EyeAnim5.png"]]];
[imageView addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"EyeAnim6.png"]]];
[imageView addObject:[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"EyeAnim7.png"]]];

imageDisplay.animationImages = imageView;
imageDisplay.animationDuration = 0.25;
imageDisplay.animationRepeatCount = 50;
[imageDisplay startAnimating];

The code seems to be crashing on the “imageDisplay.animationImages” line, as if I create the UIImageView, create its getter and setter, and build, it’s fine until I uncomment that line. If I do uncomment it, it keeps giving me the error until I delete the UIImageView and create a new one.

Not too sure what’s happening, any help appreciated!

Answer 1

animationImages array MUST contain only UIImage objects. Your array contains UIImageView objects.

Also your code is unsafe – if one of the resources will not exist app will crash (trying to add nil object to the mutable array). This will be much safer:

#define kNumberOfImages 7


NSMutableArray *imageView = [[NSMutableArray alloc] init];

for(NSUInteger i = 1; i <= kNumberOfImages; i++) {
    UIImage *anImage = [UIImage imageNamed:[NSString stringWithFormat:@"EyeAnim%d", i]];
    if(anImage) {
        [imageView addObject:anImage];
    }
}

self.imageDisplay.animationImages = imageView;
self.imageDisplay.animationDuration = 0.25;
self.imageDisplay.animationRepeatCount = 50;
[self.imageDisplay startAnimating];