// // ViewController.m // PageViewController // // Created by Tom Fewster on 11/01/2012. // #import "PagerViewController.h" @interface PagerViewController () @property (assign) BOOL pageControlUsed; @property (assign) NSUInteger page; @property (assign) BOOL rotating; - (void)loadScrollViewWithPage:(int)page; @end @implementation PagerViewController @synthesize scrollView; @synthesize pageControl; @synthesize pageControlUsed = _pageControlUsed; @synthesize page = _page; @synthesize rotating = _rotating; - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. [self.scrollView setPagingEnabled:YES]; [self.scrollView setScrollEnabled:YES]; [self.scrollView setShowsHorizontalScrollIndicator:NO]; [self.scrollView setShowsVerticalScrollIndicator:NO]; [self.scrollView setDelegate:self]; } - (BOOL)automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers { return NO; } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return YES; } - (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration { UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; [viewController willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration]; _rotating = YES; } - (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration { UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; [viewController willAnimateRotationToInterfaceOrientation:toInterfaceOrientation duration:duration]; self.scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * [self.childViewControllers count], scrollView.frame.size.height); NSUInteger page = 0; for (viewController in self.childViewControllers) { CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * page; frame.origin.y = 0; viewController.view.frame = frame; page++; } CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * _page; frame.origin.y = 0; [self.scrollView scrollRectToVisible:frame animated:NO]; } - (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation { _rotating = NO; UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; [viewController didRotateFromInterfaceOrientation:fromInterfaceOrientation]; } - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; for (NSUInteger i =0; i < [self.childViewControllers count]; i++) { [self loadScrollViewWithPage:i]; } self.pageControl.currentPage = 0; _page = 0; [self.pageControl setNumberOfPages:[self.childViewControllers count]]; UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; if (viewController.view.superview != nil) { [viewController viewWillAppear:animated]; } self.scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * [self.childViewControllers count], scrollView.frame.size.height); } - (void)viewDidAppear:(BOOL)animated { [super viewDidAppear:animated]; if ([self.childViewControllers count]) { UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; if (viewController.view.superview != nil) { [viewController viewDidAppear:animated]; } } } - (void)viewWillDisappear:(BOOL)animated { if ([self.childViewControllers count]) { UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; if (viewController.view.superview != nil) { [viewController viewWillDisappear:animated]; } } [super viewWillDisappear:animated]; } - (void)viewDidDisappear:(BOOL)animated { UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; if (viewController.view.superview != nil) { [viewController viewDidDisappear:animated]; } [super viewDidDisappear:animated]; } - (void)loadScrollViewWithPage:(int)page { if (page < 0) return; if (page >= [self.childViewControllers count]) return; // replace the placeholder if necessary UIViewController *controller = [self.childViewControllers objectAtIndex:page]; if (controller == nil) { return; } // add the controller's view to the scroll view if (controller.view.superview == nil) { CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * page; frame.origin.y = 0; controller.view.frame = frame; [self.scrollView addSubview:controller.view]; } } - (void)previousPage { if (_page - 1 > 0) { // update the scroll view to the appropriate page CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * (_page - 1); frame.origin.y = 0; UIViewController *oldViewController = [self.childViewControllers objectAtIndex:_page]; UIViewController *newViewController = [self.childViewControllers objectAtIndex:_page - 1]; [oldViewController viewWillDisappear:YES]; [newViewController viewWillAppear:YES]; [self.scrollView scrollRectToVisible:frame animated:YES]; self.pageControl.currentPage = _page - 1; // Set the boolean used when scrolls originate from the UIPageControl. See scrollViewDidScroll: above. _pageControlUsed = YES; } } - (void)nextPage { if (_page + 1 > self.pageControl.numberOfPages) { // update the scroll view to the appropriate page CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * (_page + 1); frame.origin.y = 0; UIViewController *oldViewController = [self.childViewControllers objectAtIndex:_page]; UIViewController *newViewController = [self.childViewControllers objectAtIndex:_page + 1]; [oldViewController viewWillDisappear:YES]; [newViewController viewWillAppear:YES]; [self.scrollView scrollRectToVisible:frame animated:YES]; self.pageControl.currentPage = _page + 1; // Set the boolean used when scrolls originate from the UIPageControl. See scrollViewDidScroll: above. _pageControlUsed = YES; } } - (IBAction)changePage:(id)sender { int page = ((UIPageControl *)sender).currentPage; // update the scroll view to the appropriate page CGRect frame = self.scrollView.frame; frame.origin.x = frame.size.width * page; frame.origin.y = 0; UIViewController *oldViewController = [self.childViewControllers objectAtIndex:_page]; UIViewController *newViewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; [oldViewController viewWillDisappear:YES]; [newViewController viewWillAppear:YES]; [self.scrollView scrollRectToVisible:frame animated:YES]; // Set the boolean used when scrolls originate from the UIPageControl. See scrollViewDidScroll: above. _pageControlUsed = YES; } - (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView { UIViewController *oldViewController = [self.childViewControllers objectAtIndex:_page]; UIViewController *newViewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; [oldViewController viewDidDisappear:YES]; [newViewController viewDidAppear:YES]; _page = self.pageControl.currentPage; } #pragma mark - #pragma mark UIScrollViewDelegate methods - (void)scrollViewDidScroll:(UIScrollView *)sender { // We don't want a "feedback loop" between the UIPageControl and the scroll delegate in // which a scroll event generated from the user hitting the page control triggers updates from // the delegate method. We use a boolean to disable the delegate logic when the page control is used. if (_pageControlUsed || _rotating) { // do nothing - the scroll was initiated from the page control, not the user dragging return; } // Switch the indicator when more than 50% of the previous/next page is visible CGFloat pageWidth = self.scrollView.frame.size.width; int page = floor((self.scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1; if (self.pageControl.currentPage != page) { UIViewController *oldViewController = [self.childViewControllers objectAtIndex:self.pageControl.currentPage]; UIViewController *newViewController = [self.childViewControllers objectAtIndex:page]; NSLog(@"Change page %d", page); [oldViewController viewWillDisappear:YES]; [newViewController viewWillAppear:YES]; self.pageControl.currentPage = page; [oldViewController viewDidDisappear:YES]; [newViewController viewDidAppear:YES]; _page = page; } } // At the begin of scroll dragging, reset the boolean used when scrolls originate from the UIPageControl - (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView { _pageControlUsed = NO; } // At the end of scroll animation, reset the boolean used when scrolls originate from the UIPageControl - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { _pageControlUsed = NO; } @end