Contentoffset for Tapped imageview in scrollview - iphone

Question

I am trying to save the tapped image to a photo album, using contentOffset to detect which image object is tapped to save, but it always saves the last imageObject instead.
Here is how I try to calculate contentOffset for tapped image view in scrollView:
(void)viewDidLoad
{
UIScrollView *imageScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
imageScrollView.delegate = self;
imageScrollView.pagingEnabled = YES;
for (int i = 0; i < 61; i++) {
CGFloat xOrigin = i * 320;
UIButton *myButton = [UIButton buttonWithType:UIButtonTypeCustom];
[myButton addTarget:self action:#selector(dismissView:) forControlEvents:UIControlEventTouchUpInside];
myButton.frame = CGRectMake(xOrigin, 10, 60, 35);
[myButton.layer setMasksToBounds:YES];
[myButton.layer setCornerRadius:10.0f];
myButton.layer.borderWidth = 2;
myButton.layer.borderColor = [[UIColor whiteColor] CGColor];
[myButton setTitle:#"Done" forState:UIControlStateNormal];
myButton.backgroundColor = [UIColor clearColor];
NSString *imageName = [NSString stringWithFormat:#"image%d.png", i];
UIImage *image = [UIImage imageNamed:imageName];
_imageView = [[[UIImageView alloc] initWithImage:image]autorelease];
_imageView.frame = CGRectMake(xOrigin, 0, 320, 480);
_imageView.tag = i;
[_imageScrollView viewWithTag:i+1];
UILongPressGestureRecognizer *gestureRecognizer = [[UILongPressGestureRecognizer alloc]
initWithTarget:self
action:#selector(handleLongPress:)];
imageScrollView.userInteractionEnabled = YES;
[imageScrollView addGestureRecognizer:gestureRecognizer];
gestureRecognizer.delegate = self;
[gestureRecognizer release];
[imageScrollView addSubview:_imageView];
[imageScrollView addSubview:myButton];
}
imageScrollView.contentSize = CGSizeMake(320 * 61 , 480);
[self.view addSubview:imageScrollView];
}
- (void)handleLongPress:(UILongPressGestureRecognizer*)gestureRecognizer{
if (gestureRecognizer.state == UIGestureRecognizerStateBegan){
UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:#"Cancel" destructiveButtonTitle:nil otherButtonTitles:#"Save Photo", nil];
actionSheet.actionSheetStyle = UIActionSheetStyleBlackTranslucent;
[actionSheet showInView:self.view];
[actionSheet release];
}}
-(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
switch (buttonIndex) {
case 0:
[self performSelector:#selector(LongPress:) withObject:nil];
break;
default:
break;
}}
- (void)LongPress:(UILongPressGestureRecognizer*)gestureRecognizer{
CGPoint offset = _imageScrollView.contentOffset;
int imageView = floor((Offset.x - imageView / 320) / imageView) + 1;
UIImage* image = [(UIImageView*)[_imageScrollView viewWithTag:imageView] image];
UIImageWriteToSavedPhotosAlbum(image, self, #selector(image: didFinishSavingWithError:contextInfo:), nil);
}
I expected this code to save the tapped image, but it saves the last image view from the scrollview instead.
Please let me know if I am doing it incorrectly, and if I am still missing something. Thanks for the help.

Answer 1

The reason is in your viewDidLoad you are using
_image = [UIImage imageNamed:imageName];
I think this is a global variable in the class, and you are using this object to save the image to photo album. As it is a global variable in the last count of your loop's image will be pointing to it, so you are always getting last image saved.
You can fix it by making _image local within for loop. And as you are setting the tag, using the tag you can get the imageView/image from scrollView. You can have like this
//your imageView in longPress function has the selected imageView's tag
UIImage* selImage = [(UIImageView*)[imageScrollView viewWithTag:imageView] image];
This should work for you.

Answer 2

int imageView = floor((Offset.x - imageView / 320) / imageView) + 1;
By this line
int imageView = (int)(scrollView.contentOffset.x / scrollView.frame.size.width);