Why is my UIpageControl is not displayed? - uiscrollview

Question

I downloaded a dome about UIScorllView and UIPageControl. Why UIPageControl is not display?
Here is the code ,I am new in Iphone .Any help will be appreciated!
ScrollView.M I put the ResultViewController into ScrollView. I want scroll the resultViewController with PageController.
- (void)loadScrollViewWithPage:(int)page
{
if (page < 0)
return;
if (page >= pageNumber)
return;
ResultViewController *controller = [viewControllers objectAtIndex:page];
if ((NSNull *)controller == [NSNull null])
{
controller = [[ResultViewController alloc] initWithPageNumber:page locations:existLocations];
[viewControllers replaceObjectAtIndex:page withObject:controller];
[controller release];
}
if (controller.view.superview == nil)
{
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
controller.view.frame = frame;
[scrollView addSubview:controller.view];
}
}
- (void)viewDidLoad
{
[super viewDidLoad];
existLocations = [FileManagerUtil readPlistFileForDictionary:#"Locations" fileName:#"CloudCheckLocations.plist"];
pageNumber = [existLocations count];
NSMutableArray *controllers = [[NSMutableArray alloc] init];
for (unsigned i = 0; i < pageNumber; i++)
{
[controllers addObject:[NSNull null]];
}
self.viewControllers = controllers;
[controllers release];
scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
[self.navigationItem setTitle:#"NetWork condition"];
scrollView.pagingEnabled = YES;
scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * pageNumber, scrollView.frame.size.height);
scrollView.showsHorizontalScrollIndicator = NO;
scrollView.showsVerticalScrollIndicator = NO;
scrollView.scrollsToTop = NO;
scrollView.delegate = self;
pageContronl.numberOfPages = pageNumber;
pageContronl.currentPage = 0;
[pageContronl addTarget:self action:#selector(changePage:) forControlEvents:UIControlEventValueChanged];
[pageContronl setBackgroundColor:[UIColor blackColor]];
[self loadScrollViewWithPage:0];
[self loadScrollViewWithPage:1];
[scrollView addSubview:pageContronl];
[self.view addSubview:scrollView];
}
- (void)scrollViewDidScroll:(UIScrollView *)sender
{
if (pageControlUsed)
{
return;
}
CGFloat pageWidth = scrollView.frame.size.width;
int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
pageContronl.currentPage = page;
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
pageControlUsed = NO;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
pageControlUsed = NO;
}
- (IBAction)changePage:(id)sender
{
int page = pageContronl.currentPage;
[self loadScrollViewWithPage:page - 1];
[self loadScrollViewWithPage:page];
[self loadScrollViewWithPage:page + 1];
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
[scrollView scrollRectToVisible:frame animated:YES];
pageControlUsed = YES;
}
ScrollView.h
#interface ScrollViewController : UIViewController<UIScrollViewDelegate>
{
NSMutableArray *viewControllers;
NSString *currectNetWork;
NSString *flag;
NSString *locationName;
IBOutlet UIScrollView *scrollView;
IBOutlet UIPageControl *pageContronl;
BOOL pageControlUsed;
int pageNumber;
NSMutableDictionary *existLocations;
}
#property (nonatomic,retain) NSString *currectNetWork;
#property (nonatomic,retain) NSString *flag;
#property (nonatomic,retain) NSString *locationName;
#property (nonatomic,retain) UIPageControl * pageContronl;
#property (nonatomic,retain) UIScrollView * scrollView;
#property (nonatomic,retain) NSMutableArray *viewControllers;
#property (nonatomic,retain) NSMutableDictionary *existLocations;
(IBAction)changePage:(id)sender;
ResultViewControl.M
This method will call by ScrollView.M
- (id)initWithPageNumber:(int)page locations :(NSMutableDictionary *) locations
{
titilArray = [[NSArray alloc] initWithObjects:#"Today", #"Past 7 Day",#"Past 30 Day",nil];
if (self = [super initWithNibName:#"ResultViewController" bundle:nil])
{
pageNumber = page;
existLocations = locations;
}
return self;
}

Answer 1

Check the background colour of pageControl and parent view. If both have same colour (default white) page control will not display.
In IOS6, you have new methods pageIndicatorTintColor and currentPageIndicatorTintColor.
Hope this will help.

Answer 2

Check your top and bottom constraints of container view/ tableView(if present). Both must not be attached with Top/Bottom Layout Guide. Attach them with container Margins.