UIImageView animation: manual frame advance

I am developing an iPhone app with a UIImageView. The UIImageView is populated from an NSArray. What I would like to know, is how to, instead of using the

[imageView startAnimating];

call,开发者_开发问答 how can I use a UIButton to advance between images?

here is my viewDidLoad:

- (void)viewDidLoad
{
    imageView.animationImages = [NSArray arrayWithObjects:
                                 [UIImage imageNamed:@"1.png"],
                                 [UIImage imageNamed:@"2.png"],
                                 [UIImage imageNamed:@"3.png"],
                                 nil];
;    imageView.animationDuration = 10.00;
    imageView.animationRepeatCount = 0;
    [imageView startAnimating];
    [super viewDidLoad];
    [self.view addSubview:imageView];

}

Also, I would like to know how to, based on this code, how to when the app starts, have the ImageView on image 1.png?

Thanks all.

---

You can't. [UIImage animationImages] is meant for an animation, not a slideshow-type effect. It's meant for your own implementations of UIActivityIndicator for instance.

---

Just keep an array of your UIImages handy and change the UIImageView's image property on each button press. Something like this perhaps:

// ivars
NSUInteger imageIndex;
NSArray *images;

// initialization
images = [[NSArray arrayWithObjects:
                                 [UIImage imageNamed:@"1.png"],
                                 [UIImage imageNamed:@"2.png"],
                                 [UIImage imageNamed:@"3.png"],
                                 nil] retain];
imagesIndex = 0;
imageView.image = [images objectAtIndex:imagesIndex];

and in the button's action method:

- (void)someAction:(id)sender {
  imagesIndex = (imagesIndex + 1) % [images count];
  imageView.image = [images objectAtIndex:imagesIndex];
}