Question

So, the code I use to set the image originally (it receives data from another iOS device over BlueTooth)

    UIImage *receivedImage = [UIImage imageWithData:data];
        if(receivedImage != nil)
        {
            NSLog(@"Image received is not nil.");
        }
        self.imageView.image = receivedImage;
        UIImageView *iv = [[UIImageView alloc] initWithImage:receivedImage];
        [self.view addSubview:iv];

        [self.photoAlbum addObject:receivedImage];

works like a charm with setting the image.

However, when I try to add it to the NSMutableArray property “album,” the image doesn’t change.

  -(void)stereoscopicIterationA {
    self.imageView.image = nil;
    self.imageView.image = [self.photoAlbum objectAtIndex:1];
    NSTimer *theTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(stereoscopicIterationB) userInfo:nil repeats:NO];
    NSLog(@"Image 1");

}

-(void)stereoscopicIterationB {
    self.imageView.image = nil;
    self.imageView.image = [self.photoAlbum objectAtIndex:0];
    NSTimer *theTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(stereoscopicIterationA) userInfo:nil repeats:NO];
    NSLog(@"Image 0");
}

-(void)openAlbum:(id)sender
{

    if([self.photoAlbum objectAtIndex:0] != nil && [self.photoAlbum objectAtIndex:1] == nil)
    {
    self.imageView.image = [self.photoAlbum objectAtIndex:0];


    [self dismissModalViewControllerAnimated:NO];
    }
    else if([self.photoAlbum objectAtIndex:0] !=nil && [self.photoAlbum objectAtIndex:1] !=nil ){
        //Set up NSTimer to swap self.imageView.image back and forth between 0 and 1 of photoAlbum.
        NSLog(@"Timer set up");
        NSTimer *theTimer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(stereoscopicIterationA) userInfo:nil repeats:YES];

    }

Any ideas?

More specifically, it looks like the images aren’t added/kept into the album NSMutableArray at all. The program crashes with an out of bounds error [0 .. 0].

Answer 1

It sounds, from the update to your question, as though self.photoAlbum is nil. You need to make sure you’ve allocated the array, and assigned it into self.photoAlbum.

Do this:

self.photoAlbum = [[NSMutableArray alloc] init];

before you try adding to the array.