Xcode: How do I change UIPageControl value with swipe gesture?

Question

I have a quick question I was hoping you guys could help me answer. Right now I have a UIPageControl in a storyboard which changes an image depending on what dot you are on, however, as of now you have to press on the dot to change through the dots/images, how can I change through the images/dots by swiping?

Here is my code for my .h

#import <UIKit/UIKit.h>

@interface PageViewController : UIViewController
@property (strong, nonatomic) IBOutlet UIImageView *dssview;
- (IBAction)changephoto:(UIPageControl *)sender;

@end

Here is my code for my .m

#import "PageViewController.h"

@interface PageViewController ()
@end

@implementation PageViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  if (self) {
    // Custom initialization
  }
  return self;
}

- (void)viewDidLoad
{
  [super viewDidLoad];
  // Do any additional setup after loading the view.
}

- (void)didReceiveMemoryWarning
{
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
}

- (IBAction)changephoto:(UIPageControl *)sender {
  _dssview.image = [UIImage imageNamed:
                    [NSString stringWithFormat:@"%d.jpg",sender.currentPage+1]];
}
@end

Any help would be greatly appreciated. Thanks

Sleazy

Answer 1

You can add UISwipeGestureRecognizer to your view and in the selector method of UISwipeGestureRecognizer based on the direction update the UIPageControl object, either increment the current page or decrement.

You can refer the below code. Adding swipe gesture to the view controller

UISwipeGestureRecognizer *swipeLeft = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];
swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
[self.view addGestureRecognizer:swipeLeft];

UISwipeGestureRecognizer *swipeRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe:)];
swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
[self.view addGestureRecognizer:swipeRight];

Swipe gesture selector

- (void)swipe:(UISwipeGestureRecognizer *)swipeRecogniser
{
    if ([swipeRecogniser direction] == UISwipeGestureRecognizerDirectionLeft)
    {
         self.pageControl.currentPage -=1;
    }
    else if ([swipeRecogniser direction] == UISwipeGestureRecognizerDirectionRight)
    {
         self.pageControl.currentPage +=1;
    }
    _dssview.image = [UIImage imageNamed:
                [NSString stringWithFormat:@"%d.jpg",self.pageControl.currentPage]];
}

Add an outlet to the UIPageControl in the .h file

@interface PageViewController : UIViewController
@property (strong, nonatomic) IBOutlet UIImageView *dssview;
@property (strong, nonatomic) IBOutlet UIPageControl *pageControl;

 - (IBAction)changephoto:(UIPageControl *)sender;

@end

Taro

Awesome, it says that "page" is an undeclared identifier. And where is it appropriate to add this? Any help? – Sleazy

Oh sorry! forgot to mention, page is your UIPageControl object. – Taro

Awesome I got it to work, can we make the transitions to be smoother/nicer? – Sleazy

Yes we can.. add your image views in UIScrollview. . then inside viewDidScroll: delegate method do some calculation to detect page change. – Taro

how image will identify %d.jpg. and how do this image format in my phone – Concettaconcettina