How Can I Move An UIImageView Around In A UIScrollView? - iphone

Question

In my application, I have a UIImageView inside a UIScrollView. I want to zoom and drag the UIImageView. I managed to do the zooming but I can't seem to find a way to drag the image inside the UIScrollView using touchesMoved. I have Googled around but it seems that the only method I have found was only possible in iOS 3.0+ but is now obsolete in iOS 4.0+. So how can I drag an image with my finger that is inside a UIScrollView?

Answer 1

You shouldn't need to do any touch detection yourself. UIScrollView can take care of everything.
Here's a example:
- (void)viewDidLoad
{
[super viewDidLoad];
scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
scrollView.delegate = self;
[self.view addSubview:scrollView];
imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"test.jpg"]];
scrollView.contentSize = imageView.bounds.size;
[scrollView addSubview:imageView];
float minScale = scrollView.frame.size.width / imageView.frame.size.width;
scrollView.minimumZoomScale = minScale;
scrollView.maximumZoomScale = 2.0;
scrollView.zoomScale = minScale;
}
Don't forget to add this delegate method to enable zooming:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
return imageView;
}