ios 10 Snapshotting a view that has not been rendered results in an empty snapshot - camera

Question

this question ask again but i dont find for ios 10
if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.camera)
{
self.imagePicker.delegate = self
self.imagePicker.sourceType = UIImagePickerControllerSourceType.camera;
self.imagePicker.allowsEditing = false
self.imagePicker.cameraCaptureMode = .photo
//self.imagePicker.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
self.present(self.imagePicker, animated: true, completion: nil)
self.imagePicked.isUserInteractionEnabled = true
}
else
{
print("No Camera")
}
Snapshotting a view that has not been rendered results in an empty
snapshot.Ensure your view has been rendered at least once before
snapshotting or snapshot after screen updates.
when i rotate the camera and take a shot than this error occurs.

Answer 1

Self Solution Working for me like charm :-) hope its helpful for all
DispatchQueue.global(qos: .userInitiated).async
{
self.present(self.imagePicker, animated: true, completion: nil)
}

Answer 2

I got the error
This application is modifying the autolayout engine from a background thread, which can lead to engine corruption and weird crashes...
Using DispatchQueue.main.async instead works for me.

Answer 3

This behavior is not limited to UIImagePickerController. Below is an example of a UIViewController which presents another UIViewController modally. In the second UIViewController, Safari is launched to present a URL, thus triggering the same error message, "Cannot snapshot view (>) with afterScreenUpdates:NO, because the view is not in a window. Use afterScreenUpdates:YES."
I haven't yet found any way of suppressing the message, but in my app it does no harm. I think what's going on here is that some Apple code is taking a snapshot of the app's view hierarchy, but the keyboard (which is owned by a separate UIWIndow) has not been rendered before the snapshot is taken.
/* Generates the error message:
Cannot snapshot view (<UIKeyboardImpl: 0x7f82ded12ea0; frame = (0 0; 414 271); layer = <CALayer: 0x610000035e20>>) with afterScreenUpdates:NO, because the view is not in a window. Use afterScreenUpdates:YES.
... after the "Now Tap Me, For Glory!" label is clicked
*/
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let input = UITextField()
input.placeholder = "Tap here first -- to bring up keyboard"
input.frame = CGRect(x: 10, y: 50, width: 300, height: 20)
view.addSubview(input)
let button = UIButton()
button.setTitleColor(UIColor.blue, for: .normal)
button.setTitle("Then tap here", for: .normal)
button.addTarget(self,
action: #selector(buttonPushed),
for: .touchUpInside)
button.frame = CGRect(x: 10, y: 80, width: 200, height: 20)
view.addSubview(button)
}
func buttonPushed() {
let modalVC = ModalViewController()
present(modalVC, animated: true, completion: nil)
}
}
class ModalViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = UIColor.white
let label = UILabel()
label.text = "Now Tap Me, For Glory!"
label.frame = CGRect(x: 10, y: 50, width: 300, height: 20)
view.addSubview(label)
label.isUserInteractionEnabled = true
label.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(labelTapped)))
}
func labelTapped() {
UIApplication.shared.open(URL(string: "http://planetbeagle.com")!, options: [:], completionHandler: { _ in
self.dismiss(animated: true, completion: nil) })
}
}