Question

When I press previous button it does not take any effect. Next Button is working properly but previous button do not show previous image. I am using scroll view to load images:

- (IBAction)next{
    int arraycount = [appDelegate.articles count];
    for (int nextIndex = [pageControl currentPage]; nextIndex < arraycount; nextIndex++) {  
        if ( self.scrollView.contentOffset.x <= self.scrollView.frame.size.width ) {
            CGRect frame;
            frame.origin.x = self.scrollView.contentOffset.x +     self.scrollView.frame.size.width;
            frame.origin.y = 0;
            frame.size = self.scrollView.frame.size;
            [self.scrollView scrollRectToVisible:frame animated:YES];
            pageControlBeingUsed = YES;
        }
    }
}

-(IBAction)previousButtonAction
{
    int arraycount = [appDelegate.articles count];
    NSLog(@" arraycount : %d", arraycount);
    NSLog(@" [pageControl currentPage] : %d", [pageControl currentPage]);
    for (int nextIndex = [pageControl currentPage]; nextIndex>arraycount; nextIndex--) {
        if ( self.scrollView.contentOffset.x >= self.scrollView.frame.size.width ) {
            CGRect frame;
            frame.origin.x = self.scrollView.contentOffset.x + self.scrollView.frame.size.width;
            frame.origin.y = 0;
            frame.size = self.scrollView.frame.size;
            [self.scrollView scrollRectToVisible:frame animated:YES];
            pageControlBeingUsed = YES;
        }
    } 
}

Answer 1

Okay, I now think I would approach this differently. I would check the current offset before re-assigning it.

untested code:

- (IBAction)next{
    if ( self.scrollView.contentOffset.x <= self.scrollView.frame.size.width ) {
        CGRect frame;
        frame.origin.x = self.scrollView.contentOffset.x + self.scrollView.frame.size.width;
        frame.origin.y = 0;
        frame.size = self.scrollView.frame.size;
        [self.scrollView scrollRectToVisible:frame animated:YES];
        pageControlBeingUsed = YES;
    }
}