Zooming in UIscrollview makes images subviews disappear - iphone

Question

My main motive is to create a screen just like the iPad image gallery. Images are coming from a server and can be in numbers like5 or 50 or 100. i have followed Ray Wenderlich's tutorial and gone through it step by step (http://www.raywenderlich.com/10518/how-to-use-uiscrollview-to-scroll-and-zoom-content) but still facing the issue.
I have a main scroll view (the outer) in which I want to have these images, so that I can zoom in / out each image with scrolling (and paging) feature and also when I double tap the image it should zoom to 2x and and second time double it should return to normal.
For that I have an inner scroll view which will hold an UIImageview for each image. So that each image can zoom in / out. But when I load the image I can only see the first image and other images are not displayed. when I set background color of each scroll view and the image view too I got to know that problem is with them but I can't figure out what it is:
Where is the problem in my code, I have searched a lot on internet but could not figure out, and I have tried many other samples.
Below is my code
.h file
#import <UIKit/UIKit.h>
#interface SliderViewController : UIViewController<UIScrollViewDelegate,MFMailComposeViewControllerDelegate,UIPrintInteractionControllerDelegate,UIAlertViewDelegate,UIPopoverControllerDelegate,ButtonPressedDelegate>
{
NSMutableArray *thumbsArray;
int index;
int count;
UIView *containerView;
bool isEmpty;
NSString *firstName;
NSString *lastName;
NSMutableArray *annotatedThumbsArray;
}
#property(nonatomic,retain) NSMutableArray *thumbsArray;
#property(nonatomic, assign) int index;
#property(nonatomic, assign) int count;
#property(nonatomic,retain) NSString *firstName;
#property(nonatomic,retain) NSString *lastName;
#property(nonatomic,retain) NSMutableArray *annotatedThumbsArray;
#property(nonatomic,retain) UIPopoverController *popover_controller;
#property(nonatomic,retain) IBOutlet UIScrollView *scrollView;
#property(nonatomic,retain) IBOutlet UIPageControl *pageControl;
#end
.m file:
#import "SliderViewController.h"
#import "AppDelegate.h"
#define VIEW_FOR_ZOOM_TAG (10)
#interface SliderViewController ()
{
UITapGestureRecognizer *singleFingerTap;
CGRect rect;
}
#property (nonatomic, strong) NSMutableArray *pageImages;
#property (nonatomic, strong) NSMutableArray *pageViews;
- (void)loadVisiblePages;
- (void)loadPage:(NSInteger)page;
- (void)purgePage:(NSInteger)page;
#end
implementation SliderViewController
#synthesize pageImages,pageControl,libid,libname,thumbsArray,index,count,imageNameLabel,imageNameView,footerView,navBar,firstName,lastName,annotatedThumbsArray;
#synthesize drawingViewController,popover_controller;
#synthesize pageViews = _pageViews;
#synthesize scrollView = _scrollView;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
#pragma mark - view cycle
- (void)viewDidLoad
{
[super viewDidLoad];
NSLog(#"THUMBSSSSS%#",thumbsArray);
pageImages = [[NSMutableArray alloc]init];
isEmpty = false;
self.scrollView.backgroundColor = [UIColor greenColor];
NSInteger pageCount = self.thumbsArray.count;
// Set up the page control
self.pageControl.currentPage = index;
self.pageControl.numberOfPages = pageCount;
// Set up the array to hold the views for each page
_pageViews = [[NSMutableArray alloc] init];
for (NSInteger i = 0; i < pageCount; ++i)
{
[_pageViews addObject:[NSNull null]];
}
self.navBar.topItem.title = [NSString stringWithFormat:#"%# %#",self.firstName,self.lastName];
singleFingerTap =
[[UITapGestureRecognizer alloc] initWithTarget:self
action:#selector(viewTapped:)];
[self.view addGestureRecognizer:singleFingerTap];
rect = CGRectZero;
}
- (void)centerScrollViewContents
{
CGSize boundsSize = self.scrollView.bounds.size;
CGRect contentsFrame = [self.scrollView viewWithTag:202].frame;
if (contentsFrame.size.width < boundsSize.width) {
contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
} else {
contentsFrame.origin.x = 0.0f;
}
if (contentsFrame.size.height < boundsSize.height)
{
contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
}
else
{
contentsFrame.origin.y = 0.0f;
}
[self.scrollView viewWithTag:202].frame = contentsFrame;
}
-(void)setViewContents
{
// Set up the content size of the scroll view
CGSize pagesScrollViewSize = self.scrollView.frame.size;
self.scrollView.contentSize = CGSizeMake(pagesScrollViewSize.width * self.thumbsArray.count, pagesScrollViewSize.height);
[self.scrollView setContentOffset:CGPointMake(index*pagesScrollViewSize.width, 0.0f)];
self.scrollView.delegate = self;
self.navBar.topItem.title = [NSString stringWithFormat:#"%# %#",firstName,lastName];
// Load the initial set of pages that are on screen
[self loadVisiblePages];
[self centerScrollViewContents];
}
-(void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self setViewContents];
[self performSelectorOnMainThread:#selector(showHeaderFooterViews) withObject:nil waitUntilDone:YES];
}
- (void)loadVisiblePages
{
// First, determine which page is currently visible
CGFloat pageWidth = self.scrollView.frame.size.width;
NSInteger page = (NSInteger)floor((self.scrollView.contentOffset.x * 2.0f + pageWidth) / (pageWidth * 2.0f));
// Update the page control
self.pageControl.currentPage = page;
// Work out which pages you want to load
isEmpty = false;
NSInteger firstPage = page - 1;
NSInteger lastPage = page + 1;
// Purge anything before the first page
for (NSInteger i=0; i<firstPage; i++) {
[self purgePage:i];
}
for (NSInteger i=firstPage; i<=lastPage; i++) {
[self loadPage:i];
}
for (NSInteger i=lastPage+1; i<self.thumbsArray.count; i++) {
[self purgePage:i];
}
thumbnail *tempThumb = [[thumbnail alloc]init];
tempThumb = [thumbsArray objectAtIndex:page];
NSString *image_name = [[NSString alloc]initWithFormat:#"%#",tempThumb.name];
tempThumb = nil;
[self.imageNameLabel setText:[NSString stringWithFormat:#"%#(%d/%d)",image_name,pageControl.currentPage+1,pageControl.numberOfPages]];
}
-(void)purgePage:(NSInteger)page
{
if(page < 0 || page >= self.thumbsArray.count+self.annotatedThumbsArray.count)
{
// If it's outside the range of what you have to display, then do nothing
return;
}
// Remove a page from the scroll view and reset the container array
UIView *pageView = [_pageViews objectAtIndex:page];
if ((NSNull*)pageView != [NSNull null])
{
[pageView removeFromSuperview];
[_pageViews replaceObjectAtIndex:page withObject:[NSNull null]];
}
}
- (void)loadPage:(NSInteger)page
{
#try
{
if (page < 0 || page >= self.thumbsArray.count)
{
// If it's outside the range of what we have to display, then do nothing
return;
}
// Load an individual page, first checking if you've already loaded it
UIView *pageView = [_pageViews objectAtIndex:page]; // page views holds
if ((NSNull*)pageView == [NSNull null] || isEmpty)
{
CGRect frame = self.scrollView.bounds;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0.0f;
frame = CGRectInset(frame, 10.0f, 0.0f);
thumbnail *tempThumb = [[thumbnail alloc]init];
tempThumb = [thumbsArray objectAtIndex:page];
NSString *image_name = [[NSString alloc]initWithFormat:#"%#",tempThumb.name];
tempThumb = nil;
NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
NSString *documentDir = [path objectAtIndex:0];
NSString *docsPath = [documentDir stringByAppendingPathComponent:[NSString stringWithFormat:#"downloaded/%#",libid]];
UIImage *fullImage = [[UIImage alloc]init];
NSString *imagePath;
if(page<(thumbsArray.count-annotatedThumbsArray.count))
{
imagePath = [docsPath stringByAppendingPathComponent:image_name];
}
else
{
documentDir = [documentDir stringByAppendingPathComponent:libid];
imagePath = [documentDir stringByAppendingPathComponent:image_name];
}
BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:imagePath];
if(fileExists)
{
NSLog(#"file NAMEEEE: - %#",image_name);
fullImage = [UIImage imageWithContentsOfFile:imagePath];
}
else
{
NSLog(#"FILE NOT FOUND");
fullImage = [UIImage imageNamed:#"noimage.jpg"];
isEmpty = true;
}
UIImageView *newPageView = [[UIImageView alloc] initWithImage:fullImage];
[newPageView setUserInteractionEnabled:YES];
newPageView.contentMode = UIViewContentModeScaleAspectFit;
newPageView.frame = frame;
newPageView.backgroundColor = [UIColor blueColor];
newPageView.tag = VIEW_FOR_ZOOM_TAG;
// ******* add each image view into a scroll view so that it can be zoomed and also can be swiped
UIScrollView *pageScrollView = [[UIScrollView alloc] initWithFrame:frame];
pageScrollView.tag = 202;
pageScrollView.minimumZoomScale = 1.0f;
pageScrollView.maximumZoomScale = 2.0f;
pageScrollView.zoomScale = 1.0f;
// pageScrollView.contentSize = newPageView.bounds.size;
pageScrollView.delegate = self;
pageScrollView.showsHorizontalScrollIndicator = NO;
pageScrollView.showsVerticalScrollIndicator = NO;
pageScrollView.backgroundColor = [UIColor yellowColor];
[self.scrollView addSubview:pageScrollView];
[pageScrollView addSubview:newPageView];
[self.scrollView bringSubviewToFront:pageScrollView];
NSLog(#"frame --> %f", frame.origin.x);
NSLog(#"frame --> %f", newPageView.frame.origin.x);
NSLog(#"frame --> %f", pageScrollView.frame.origin.x);
[self.pageViews replaceObjectAtIndex:page withObject:newPageView];
UITapGestureRecognizer *doubleTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(viewDoubleTapped:)];
doubleTapRecognizer.numberOfTapsRequired = 2;
doubleTapRecognizer.numberOfTouchesRequired = 1;
[newPageView addGestureRecognizer:doubleTapRecognizer];
}
}
#catch (NSException *exception)
{
NSLog(#"crash in - loadPage = %#", exception);
}
#finally {
// NSLog(#"finally-");
}
}
#pragma mark - double tapped
-(void)viewDoubleTapped:(UITapGestureRecognizer*)recognizer
{
//TODO: code for 2x zooming in / out
}
#pragma mrak - view tapped
-(void) viewTapped:(UITapGestureRecognizer*)recognizer
{
if([self.footerView isHidden])
{
[self performSelectorOnMainThread:#selector(showHeaderFooterViews) withObject:nil waitUntilDone:YES];
}
}
- (void)showHeaderFooterViews
{
[self.imageNameView setHidden:NO];
[self.footerView setHidden:NO];
[self performSelector:#selector(hideHeaderFooterViews) withObject:nil afterDelay:5.0];
}
- (void)hideHeaderFooterViews
{
NSLog(#"hide header footer called ");
[self.imageNameView setHidden:YES];
[self.footerView setHidden:YES];
}
#pragma mark - back button (cross button ) pressed
- (IBAction)backButtonPressed:(id)sender
{
#try
{
AppDelegate* myAppDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];
int l = [[[myAppDelegate window].rootViewController childViewControllers] count];// to access the previous controller
FolderViewController *parentVC = (FolderViewController *)((UITabBarController *)[[[myAppDelegate window].rootViewController childViewControllers] objectAtIndex:l-2]); // accessing FolderviewC
[parentVC loadThumbnails];
[self.view removeFromSuperview];
[self removeFromParentViewController];
}
#catch (NSException *exception) {
NSLog(#"crash in SliderVC: backButtonPressed - %#", exception);
}
#finally {
}
}
#pragma mark - scroll view delegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
// Load the pages that are now on screen
[self loadVisiblePages];
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
if(scrollView.tag == 202)
return [scrollView viewWithTag:VIEW_FOR_ZOOM_TAG];
return nil;
}
- (void)scrollViewDidZoom:(UIScrollView *)scrollView
{
NSLog(#"view zoomed");
[self centerScrollViewContents ];
}
- (void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view
{
NSLog(#"Beginning zooming");
}
- (void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(float)scale{
NSLog(#"Zooming Did End");
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)swipeRight:(id)sender
{
if (!((self.scrollView.contentOffset.x+self.scrollView.frame.size.width) >= self.scrollView.contentSize.width))
{
[self.scrollView setContentOffset:CGPointMake(self.scrollView.contentOffset.x+self.scrollView.frame.size.width, self.scrollView.contentOffset.y)];
[self loadVisiblePages];
}
}
- (IBAction)swipeLeft:(id)sender
{
if (!((self.scrollView.contentOffset.x-self.scrollView.frame.size.width) < 0))
{
[self.scrollView setContentOffset:CGPointMake(self.scrollView.contentOffset.x-self.scrollView.frame.size.width, self.scrollView.contentOffset.y)];
[self loadVisiblePages];
}
}
NOTE: I have saved my images which I am getting from server in Documents directory and accessing back them from my loadPage: method (is this the right place to access these images?)