Enable paging in UIScrollView after scaling

Question

I have a UIScrollView that loads three different pages.
When I zoom in on the page and zoom in to the original size, the application stops letting me scroll pages as if paging is disabled. What can I do to re-enable paging when zooming in to its original size (Scale == 1)?

This is my code.

 - (void)viewDidLoad { [ScView setMaximumZoomScale : 2.0f]; [ScView setMinimumZoomScale : 1.0f]; ScView.contentSize = CGSizeMake(1024*3, 1.0); ScView.pagingEnabled = YES; ScView.clipsToBounds = YES; ScView.delegate = self; ScView.showsHorizontalScrollIndicator = NO; ScView.showsVerticalScrollIndicator = NO; [super viewDidLoad]; [self returnImages]; } -(void)returnImages{ for (pageNumber = 1; pageNumber <= 3; pageNumber++) { imagen = [[UIImageView alloc] initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"%d.png",pageNumber]]]; imagen.frame = CGRectMake((pageNumber-1)*1024, 0, 1024, 768); [ScView addSubview:imagen]; } } // - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{ return ScView; // return [imagen initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"%d.png",pageNumber]]]; } - (void)scrollViewWillBeginZooming:(UIScrollView *)myScrollView withView:(UIView *)view { NSLog(@"Scroll Will Begin"); ScView.scrollEnabled = YES; } - (void)scrollViewDidEndZooming:(UIScrollView *)myScrollView withView:(UIView *)view atScale:(float)scale { if(scale == 1) { ScView.scrollEnabled = YES; ScView.pagingEnabled = YES; [self returnImages]; NSLog(@"Scrolol will end"); //ScView.maximumZoomScale = 2.0f; // [super viewDidLoad]; [self returnImages]; } } 

Any ideas would be highly appreciated.

Answer 1

To get the right swap and scale, you must embed the UIScrollView for each page in your parent UIScrollView. This combination will allow you to use simultaneous swapping and internal scrolling.

Here is an example of a UIViewController with a parent scroll view and three built-in scalable pages.

 #define VIEW_FOR_ZOOM_TAG (1) @implementation SVViewController - (void)viewDidLoad { [super viewDidLoad]; UIScrollView *mainScrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds]; mainScrollView.pagingEnabled = YES; mainScrollView.showsHorizontalScrollIndicator = NO; mainScrollView.showsVerticalScrollIndicator = NO; CGRect innerScrollFrame = mainScrollView.bounds; for (NSInteger i = 0; i < 3; i++) { UIImageView *imageForZooming = [[UIImageView alloc] initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"page%d", i + 1]]]; imageForZooming.tag = VIEW_FOR_ZOOM_TAG; UIScrollView *pageScrollView = [[UIScrollView alloc] initWithFrame:innerScrollFrame]; pageScrollView.minimumZoomScale = 1.0f; pageScrollView.maximumZoomScale = 2.0f; pageScrollView.zoomScale = 1.0f; pageScrollView.contentSize = imageForZooming.bounds.size; pageScrollView.delegate = self; pageScrollView.showsHorizontalScrollIndicator = NO; pageScrollView.showsVerticalScrollIndicator = NO; [pageScrollView addSubview:imageForZooming]; [mainScrollView addSubview:pageScrollView]; if (i < 2) { innerScrollFrame.origin.x += innerScrollFrame.size.width; } } mainScrollView.contentSize = CGSizeMake(innerScrollFrame.origin.x + innerScrollFrame.size.width, mainScrollView.bounds.size.height); [self.view addSubview:mainScrollView]; } - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView { return [scrollView viewWithTag:VIEW_FOR_ZOOM_TAG]; } - (NSUInteger)supportedInterfaceOrientations { return UIInterfaceOrientationMaskPortrait; } - (BOOL)shouldAutorotate { return NO; } @end 

Answer 2

I follow the @NikNarmo solution, I will write a small quick xcode project to demonstrate the scaling and swap functions.

We hope to help everyone who wants to accomplish the same task.

Some codes from UIScrollView Tutorial: Getting started http://www.raywenderlich.com/76436/use-uiscrollview-scroll-zoom-content-swift ,

and some of A Beginners' Guide for UIScrollView http://www.appcoda.com/uiscrollview-introduction/ .

Using Xcode 7.0 and Swift 2.0

  override func viewDidLoad() { super.viewDidLoad() mainScrollView = UIScrollView(frame: self.view.bounds) mainScrollView.pagingEnabled = true mainScrollView.showsHorizontalScrollIndicator = false mainScrollView.showsVerticalScrollIndicator = false pageScrollViews = [UIScrollView?](count: photos.count, repeatedValue: nil) let innerScrollFrame = mainScrollView.bounds mainScrollView.contentSize = CGSizeMake(innerScrollFrame.origin.x + innerScrollFrame.size.width, mainScrollView.bounds.size.height) mainScrollView.backgroundColor = UIColor.redColor() mainScrollView.delegate = self self.view.addSubview(mainScrollView) configScrollView() addPageControlOnScrollView() } 

and the magic is in func scrollViewWillEndDragging when contentSize is equal to mainScrollViewContentSize or not, if it is mainScrollViewController, then swap, otherwise do nothing.

  func scrollViewWillEndDragging(scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) { let targetOffset = targetContentOffset.memory.x let zoomRatio = scrollView.contentSize.height / mainScrollViewContentSize.height if zoomRatio == 1 { // mainScrollViewController let mainScrollViewWidthPerPage = mainScrollViewContentSize.width / CGFloat(pageControl.numberOfPages) let currentPage = targetOffset / (mainScrollViewWidthPerPage * zoomRatio) pageControl.currentPage = Int(currentPage) loadVisiblePages() } else { // pageScorllViewController } } 

And here is the project code https://github.com/Charles-Hsu/ScrollViewDemo