Wrapping up multiple images in a single horizontal slideshow is a common task while developing iOS apps. Don’t think of it as the same old slider that you can see on webpages. Slideshows can be more common and useful than you might think.

Applications

Slideshows are useful for feed content like posts, contests, carousels (not real carousels but similar ones), and way more. I’ve used slideshows in a great variety of iOS apps, and they’ve always helped me when I needed to show multiple images inside small views.

Moreover, you can apply user interactions to them easily with gesture recognizers, providing the swipe behavior to show next and previous items inside the container and even tap or long-press gestures to apply events.

UIScrollView — It’s All You Need

First of all, let’s take a look at this UIView subclass. UIScrollView incorporates the behavior of encapsulating content that simply “scrolls” horizontally or vertically. UITableViews, UICollectionViews, and UI objects like these are simply subclasses of the UIScrollView class. They all scroll in a similar manner, actually.

The good thing about using UIScrollViews is that they provide delegation methods that let you benefit from having “hooks” and customize behaviors and code applications while the UIScrollView scrolls, stops scrolling, starts scrolling, or even decelerates.

Let’s take a look at the fundamental properties of the UIScrollView object:

• contentSize: CGSize. Determine the content size of the UIScrollView. It’s used to specify how long the content inside the UIScrollView is.
• contentOffset: CGPoint. It specifies the offset of the content using a CGPoint that has x and y coordinates. It’s used to offset the content (e.g. to “move” the content inside the UIScrollView).
• contentInset: UIEdgeInsets. As any UIEdgeInset object, it’s used to set an inset space inside the UIScrollView. It’s like applying padding inside the UIScrollView.
• isScrollEnabled: Bool. Determines if the UIScrollView should scroll. Useful when you have to lock or unlock the user interaction on the UIScrollView.
• isPagingEnabled: Bool. If enabled, it makes the UIScrollView scrolling using pagination and avoiding a free and undetermined scrolling behavior. So if you swipe left for example, the UIScrollView slips to the next paged content.
• bounces: Bool. If enabled, makes the UIScrollView bounces when its content come to the end or the beginning, providing the classic bouncing effect that you can see in many UI iOS controls.

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