Using a UIButton to update the image in a UIImageView - objective-c

Question

I'm really new to app development and I am building an app (that will be more complex but this is just the basis of it which I will later expand). What I have currently is view with a UIImageView and UIButton, code below. I can get the button to set an image from the resources folder, but what I want is for the button to update the UIImageView with a new image each time it is press e.g. press once = image1, pressed twice = image2...etc From what I have been reading I think I should have the images in an array with a key or something then I can just update it with ++ I know this is really vague but as I said I'm really new so any help would be greatly appreciated!
#interface NextImageViewController : UIViewController {
IBOutlet UIImageView *imageView;
}
- (IBAction) nextImagePush;
#end
#implementation NextImageViewController
- (IBAction) nextImagePush {
UIImage *img = [UIImage imageNamed:#"image1"];
[imageView setImage:img];
}

Answer 1

#interface NextImageViewController : UIViewController {
IBOutlet UIImageView *imageView;
NSInteger imageCount;
NSArray * imageArray;
}
- (IBAction) nextImagePush;
#end
#implementation NextImageViewController
- (IBAction) nextImagePush {
UIImage *img = [UIImage imageNamed:[imageArray objectAtIndex:imageCount]];
[imageView setImage:img];
imageCount++;
if (imageCount >= [imageArray count]){
imageCount = 0;
}
}
- (void) viewDidLoad {
imageArray = [[NSArray alloc]
initWithObjects:#"image1", #"image2", #"image3", nil];
imageCount = 0;
}
Try something like that. You wil have to set the initial image and change the count depending on what you set it.

Answer 2

You can simply create a NSArray or NSMutableArray and fill it with all the images you want to show. Then, using a variable visible at global scope (ie a field of your interface), you can use
[imageView setImage:[arrayOfImages objectAtIndex:(index++ % [arrayOfImages count])]];
This code will also show the first image after the last one is displayed.

Answer 3

A really rudimentary way to do this is set a integer. Define it as 0,
and the first time you click the button you add 1 to it.
This definitely isn't working code, but its just to help you get a start. I strongly suggest a book like Big Nerd Ranch's book on iOS or Beginning IPhone 4 Development.
-(IBAction)pic
if variable == 0 {
//show the first image
variable++;
}
else if variable == 1 {
//show the second image
variable++;
}