Page Control in iPhone

In this article I will explain how to implement a Page Control in an iPhone.

Introduction

In this article I will create a Single View application. Here I implement a Page controller. Using it we can add more than one image in a single view using a Page Control. Here we add a Page Control and image view from outlet.

To understand it we use the following.

Step 1

Open XCode by double-clicking on it.

Step 2

Create a New XCode Project by clicking on it.

Step 3

Now select Single View Application and click on "Next".

Step 4

Now provide your Product Name and Company Identifier.

Step 5

Select the location where you want to save your project and click on "Create".

Step 6 

Now here we write the code.

AppDelegate.h

#import <UIKit/UIKit.h>
@class ViewController;
@interface AppDelegate : UIResponder <UIApplicationDelegate>
@property (strong, nonatomic) UIWindow *window;
@property (strong, nonatomic) ViewController *viewController;
@end

AppDelegate.m

#import "AppDelegate.h"
#import "ViewController.h"

@implementation AppDelegate
- (void)dealloc
{
[_window release];
[_viewController release];
[super dealloc];
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
// Override point for customization after application launch.
self.viewController = [[[ViewController alloc] initWithNibName:@"ViewController" bundle:nil] autorelease];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES;
}
@end

ViewController.h

#import <UIKit/UIKit.h>
@interface ViewController : UIViewController<UIScrollViewDelegate>{
IBOutlet UIScrollView* scrollView;
IBOutlet UIPageControl* pageControl;
BOOL pageControlIsChangingPage;
}
@property (nonatomic, retain) UIView *scrollView;
@property (nonatomic, retain) UIPageControl* pageControl;
- (IBAction)changePage:(id)sender;
- (void)setupPage;
@end

ViewController.m

#import "ViewController.h"
@implementation ViewController
@synthesize scrollView;
@synthesize pageControl;
- (void)viewDidLoad
{
[self setupPage];
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (void)viewDidUnload
{
[scrollView release];
[pageControl release];
}
- (void)dealloc
{
[super dealloc];
}
- (void)setupPage
{
scrollView.delegate = self;
[self.scrollView setBackgroundColor:[UIColor blackColor]];
[scrollView setCanCancelContentTouches:NO];
scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
scrollView.clipsToBounds = YES;
scrollView.scrollEnabled = YES;
scrollView.pagingEnabled = YES;
NSUInteger nimages = 0;
CGFloat cx = 0;
for (; ; nimages++) {
NSString *imageName = [NSString stringWithFormat:@"image%d.jpg", (nimages + 1)];
UIImage *image = [UIImage imageNamed:imageName];
if (image == nil) {
break;
}
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
CGRect rect = imageView.frame;
rect.size.height = image.size.height;
rect.size.width = image.size.width;
rect.origin.x = ((scrollView.frame.size.width - image.size.width) / 2) + cx;
rect.origin.y = ((scrollView.frame.size.height - image.size.height) / 2);
imageView.frame = rect;
[scrollView addSubview:imageView];
[imageView release];
cx += scrollView.frame.size.width;
}
self.pageControl.numberOfPages = nimages;
[scrollView setContentSize:CGSizeMake(cx, [scrollView bounds].size.height)];
}
#pragma mark -
#pragma mark UIScrollViewDelegate stuff
- (void)scrollViewDidScroll:(UIScrollView *)_scrollView
{
if (pageControlIsChangingPage) {
return;
}
CGFloat pageWidth = _scrollView.frame.size.width;
int page = floor((_scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
pageControl.currentPage = page;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView
{
pageControlIsChangingPage = NO;
}
- (IBAction)changePage:(id)sender
{
CGRect frame = scrollView.frame;
frame.origin.x = frame.size.width * pageControl.currentPage;
frame.origin.y = 0;
[scrollView scrollRectToVisible:frame animated:YES];
pageControlIsChangingPage = YES;
}
@end

ViewController.Xib

Step 7

Finally we click on the run button to show the output.

Step 8

Output 1 in iPhone:

Output 2 in iPhone:

Output 3 in iPhone:

Output 4 in iPhone:

Output 5 in iPhone: