Postioning UIImageSubview at center in UIScrollview - iphone

Question

How to position the UIImageSubview at center in UIScrollview , I am Loading images dynalically in the uiscrollview so when i select any image in the Uiscrollview that Image should display at the center of screen in uiscrollview.
My Image Width is 65 and Screen width is 320 , I am facing problem setting the position of choosen image at the center of screen,
[scrollView1 setContentOffset:CGPointMake(130, 0) animated:YES];
scrollview just scroll to the 130 position. I don't want like this , I want the subview should be displayed at the center.
Please see the screenshot and tell me how to solve this problem.

Answer 1

How about
(pseudocode)
contentOffset.x = image.center.x - (screenwidth/2)
(expanded...)
UIImageView* imageView = //imageview that was selected
CGFloat screenWidth = 320;
CGPoint offset = scrollView1.contentOffset;
offset.x = imageView.center.x - screenWidth/2;
[scrollView1 setContentOffset:offset animated:YES];
I assume you already worked out how to get a pointer to the selected image...
(expanded further...)
Here is a fully-worked out version of the same, using buttons instead of images for ease of selection... try it (just copy into a new single-view project's viewContoller]), you will see that it works. If you are still having problems I expect it is the way you are identifying your image as the selected image for centering. You would need to update your question showing your code...
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect frame = self.view.bounds;
frame.size.height = frame.size.height/2;
self.scrollView = [[UIScrollView alloc] initWithFrame:frame];
[self.view addSubview:self.scrollView];
[self.scrollView setContentSize:CGSizeMake(2000,self.scrollView.bounds.size.height)];
[self.scrollView setDelegate:self];
for (int i = 1; i < 20; i++) {
UIButton* button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
NSString* title = [NSString stringWithFormat:#"button %d",i];
[button setTitle:title forState:UIControlStateNormal];
button.bounds = CGRectMake(0,0,80,60);
button.center = CGPointMake(i*100+50,self.scrollView.bounds.size.height/2);
[button addTarget:self
action:#selector(buttonPressed:)
forControlEvents:UIControlEventTouchUpInside];
[self.scrollView addSubview:button];
}
}
- (void)buttonPressed:(UIButton*)sender
{
CGFloat x = sender.center.x - self.scrollView.bounds.size.width/2.0f;
[self.scrollView setContentOffset:CGPointMake(x,0) animated:YES];
}