With Swift 4 / iOS 10.3, you can choose one of the following ways in order to solve your problem.
1. Take a screenshot of a view controller's view
The following code shows how to take a screenshot and save it in the device photo album:
import UIKit
class ViewController: UIViewController {
/* ... */
@IBAction func screenshot(_ sender: UIBarButtonItem) {
//Create the UIImage
UIGraphicsBeginImageContextWithOptions(view.frame.size, true, 0)
guard let context = UIGraphicsGetCurrentContext() else { return }
view.layer.render(in: context)
guard let image = UIGraphicsGetImageFromCurrentImageContext() else { return }
UIGraphicsEndImageContext()
//Save it to the camera roll
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
}
}
Note that the result of this code will be a .JPG image. Also note that the navigation bar and the status bar will not appear in the final image.
Since iOS 10, as an alternative to the previous code, you can use the code below:
import UIKit
class ViewController: UIViewController {
/* ... */
@IBAction func screenshot(_ sender: UIBarButtonItem) {
//Create the UIImage
let renderer = UIGraphicsImageRenderer(size: view.frame.size)
let image = renderer.image(actions: { context in
view.layer.render(in: context.cgContext)
})
//Save it to the camera roll
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
}
}
2. Take a screenshot of an iPhone window
If you want to take a screenshot that includes the navigation bar (but not the status bar), you can use the following code:
import UIKit
class ViewController: UIViewController {
/* ... */
@IBAction func screenshot(_ sender: UIBarButtonItem) {
//Create the UIImage
guard let layer = UIApplication.shared.keyWindow?.layer else { return }
UIGraphicsBeginImageContextWithOptions(layer.frame.size, true, 0)
guard let context = UIGraphicsGetCurrentContext() else { return }
layer.render(in: context)
guard let image = UIGraphicsGetImageFromCurrentImageContext() else { return }
UIGraphicsEndImageContext()
//Save it to the camera roll
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
}
}
Since iOS 10, as an alternative to the previous code, you can use the code below:
import UIKit
class ViewController: UIViewController {
/* ... */
@IBAction func screenshot(_ sender: UIBarButtonItem) {
//Create the UIImage
guard let layer = UIApplication.shared.keyWindow?.layer else { return }
let renderer = UIGraphicsImageRenderer(size: layer.frame.size)
let image = renderer.image(actions: { context in
layer.render(in: context.cgContext)
})
//Save it to the camera roll
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil)
}
}
Reminder
Since iOS 10, in order to prevent your app from crashing when calling your screenshot(_:)
method, you need to add the key NSPhotoLibraryUsageDescription
to your project's Info.plist file:
<key>NSPhotoLibraryUsageDescription</key>
<string>Some description to explain why access is required</string>