How to print using UIActivityViewController

Swift version: 5.1

Paul Hudson @twostraws May 28th 2019

Printing in iOS used to be done using UIPrintInteractionController, and, while that still works, it has a much better replacement in the form of UIActivityViewController. This new class is responsible for taking a wide variety of actions of which printing is just one, but users can also tweet, post to Facebook, send by email, and any other action that has been registered by another app.

If you have a UIImage you want to print, you can just pass it in. If you want to print text, you can wrap it inside an NSAttributedString with some formatting, then place that inside a UISimpleTextPrintFormatter object, then print that – iOS automatically takes care of pagination, margins and more.

Below are two example functions that print an image and some text to help get you started:

func share(image: UIImage) {
    let vc = UIActivityViewController(activityItems: [image], applicationActivities: [])
    present(vc, animated: true)
}

func share(text: String) {
    let attrs = [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 72), NSAttributedString.Key.foregroundColor: UIColor.red]
    let str = NSAttributedString(string: text, attributes: attrs)
    let print = UISimpleTextPrintFormatter(attributedText: str)

    let vc = UIActivityViewController(activityItems: [print], applicationActivities: nil)
    present(vc, animated: true)
}

Available from iOS 6.0 – see Hacking with Swift tutorial 3