How to change text label when scroll view goes to view 2? - ios

Question

I'm making a select level with 3 levels that get scrolled horizontally - the scroll controls three views "View 1" "view 2" and "View 3", I need to make an illusion to the user, Ive placed 3 buttons on each view and half a button on each side of the UIview with 2 labels one writes "lev" the other "el 2"...
When the user moves to View 2 I'd like the label to be set to "el 2" and as soon as the scroll has settled on level 2 i'd like the label to write "el 1" - This would make an illusion and it would be so fast that the user wouldn't notice.
heres the code:
This:
[_elone setText:[NSString stringWithFormat:#"Level 2"]];
But I don't know where to put it,
Should I make an outlet, an action a statement?
#interface PagerViewController ()
#property (assign) BOOL pageControlUsed;
#property (assign) NSUInteger page;
#property (assign) BOOL rotating;
- (void)loadScrollViewWithPage:(int)page;
#end
#implementation PagerViewController
#synthesize scrollViewTwo;
#synthesize pageControlTwo;
#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.scrollViewTwo setPagingEnabled:YES];
[self.scrollViewTwo setScrollEnabled:YES];
[self.scrollViewTwo setShowsHorizontalScrollIndicator:NO];
[self.scrollViewTwo setShowsVerticalScrollIndicator:NO];
[self.scrollViewTwo setDelegate:self];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
for (NSUInteger i =0; i < [self.childViewControllers count]; i++) {
[self loadScrollViewWithPage:i];
}
self.pageControlTwo.currentPage = 0;
_page = 0;
[self.pageControlTwo setNumberOfPages:[self.childViewControllers count]];
UIViewController *viewController = [self.childViewControllers objectAtIndex:self.pageControlTwo.currentPage];
if (viewController.view.superview != nil) {
[viewController viewWillAppear:animated];
}
self.scrollViewTwo.contentSize = CGSizeMake(scrollViewTwo.frame.size.width * [self.childViewControllers count], scrollViewTwo.frame.size.height);
}
- (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.scrollViewTwo.frame;
frame.origin.x = frame.size.width * page;
frame.origin.y = 0;
controller.view.frame = frame;
[self.scrollViewTwo addSubview:controller.view];
}
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
_pageControlUsed = NO;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
_pageControlUsed = NO;
}
- (IBAction) changePage :(id) sender {
}
How is this done?

Answer 1

// Implement the UIScrollview Delegate method
-(void)scrollViewDidScroll:(UIScrollView *)sender
{
CGFloat pageWidth = yourScrollView.frame.size.width;
int currentPage = floor((yourScrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
if (currentPage != featureVenPageControll.currentPage)
{
[_elone setText:[NSString stringWithFormat:#"Level 2"]];
}
}