I am making a simple slideshow view within my app. I'd like to link my UIPageControl to my UIScrollView. This shouldn't be too difficult, but I haven't been able to find a simple solution anywhere. Below is my code.
HelpViewController.h
#import <UIKit/UIKit.h>
@interface HelpViewController : UIViewController{
}
@end
HelpViewController.m
#import "HelpViewController.h"
@interface HelpViewController ()
@end
@implementation HelpViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect scrollViewFrame = CGRectMake(0, 62, 320, 404);
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:scrollViewFrame];
[self.view addSubview:scrollView];
CGSize scrollViewContentSize = CGSizeMake(640, 404);
[scrollView setContentSize:scrollViewContentSize];
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(200, 200, 50, 21)];
[label setText:@"Hello"];
[scrollView addSubview:label];
[scrollView setPagingEnabled:YES];
scrollView.showsHorizontalScrollIndicator = NO;
UIPageControl *pageControl = [[UIPageControl alloc] init];
pageControl.frame = CGRectMake(110,5,100,100);
pageControl.numberOfPages = 2;
pageControl.currentPage = 0;
[self.view addSubview:pageControl];
pageControl.backgroundColor = [UIColor redColor];
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
@end
Maybe this works for you
Don't forget to set the UIScrollView's delegate = self (or wherever you have the selector below).
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat pageWidth = self.scrollView.frame.size.width; // you need to have a **iVar** with getter for scrollView
float fractionalPage = self.scrollView.contentOffset.x / pageWidth;
NSInteger page = lround(fractionalPage);
self.pageControl.currentPage = page; // you need to have a **iVar** with getter for pageControl
}
For your code it then would be:
.h file
#import <UIKit/UIKit.h>
@interface HelpViewController : UIViewController{
}
@property (nonatomic, retain) UIScrollView *scrollView;
@property (nonatomic, retain) UIPageControl * pageControl;
@end
.m file
#import "HelpViewController.h"
@interface HelpViewController ()
@end
@implementation HelpViewController
@synthesize scrollView=scrollView_;
@synthesize pageControl=pageControl_;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
CGRect scrollViewFrame = CGRectMake(0, 62, 320, 404);
self.scrollView = [[[UIScrollView alloc] initWithFrame:scrollViewFrame] autorelease];
self.scrollView.delegate = self;
[self.view addSubview:self.scrollView];
CGSize scrollViewContentSize = CGSizeMake(640, 404);
[self.scrollView setContentSize:scrollViewContentSize];
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(200, 200, 50, 21)];
[label setText:@"Hello"];
[self.scrollView addSubview:label];
[self.scrollView setPagingEnabled:YES];
self.scrollView.showsHorizontalScrollIndicator = NO;
self.pageControl = [[[UIPageControl alloc] init] autorelease];
self.pageControl.frame = CGRectMake(110,5,100,100);
self.pageControl.numberOfPages = 2;
self.pageControl.currentPage = 0;
[self.view addSubview:self.pageControl];
pageControl.backgroundColor = [UIColor redColor];
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat pageWidth = self.scrollView.frame.size.width;
float fractionalPage = self.scrollView.contentOffset.x / pageWidth;
NSInteger page = lround(fractionalPage);
self.pageControl.currentPage = page;
}
@end