I need to prevent screen capture by users of my app, for security reasons. The contents I display are confidential and should not be copied onto the device. I saw one answer on Stack Overflow, but for Android.
Is it possible somehow in iOS to prevent screen capture?
While capturing the screenshot into the gallery by the click of few buttons is a very useful feature for the user, there is a limited requirement to prevent it too. Any pointers?
I've just wrote simple extension of UIView that allows to hide it from screen-capturing, Airplay mirroring and so on. The solution uses ability of UITextField to hide a password from capturing.
extension UIView {
func makeSecure() {
DispatchQueue.main.async {
let field = UITextField()
field.isSecureTextEntry = true
field.isUserInteractionEnabled = false
self.addSubview(field)
field.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
field.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
self.layer.superlayer?.addSublayer(field.layer)
field.layer.sublayers?.first?.addSublayer(self.layer)
}
}
}
using:
class ViewController: UIViewController {
var secureView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
secureView.makeSecure()
}
}
I'll be grateful if someone explains how Apple does this magic inside.
_UITextLayoutCanvasView is responsible for hiding things (see gist.github.com/damian-rzeszot/bbfd92895dfe9400ba9a7cf2a0c1e670) –
Nimmons field.layer.sublayers?.last?.addSublayer(self.layer) seems to work on iOS17 –
Vespucci There's no way to prevent taking screenshots entirely. You can do what Snapchat does, which is by requiring the user to be touching the screen to view whatever information you're displaying. This is because the system screenshot event interrupts touches. It's not a perfect method and you can't prevent users from taking screenshots 100% of the time.
More details: iOS Detection of Screenshot?
It's been a while, but I just came across ScreenShieldKit, which is a patent-pending technology used by the messaging app Confide. What it does is that it let's the user take screenshots, but the content is blank on the end picture. They recently released the iOS version.
Remove sensitive information from views before moving to the background. When an application transitions to the background, the system takes a snapshot of the application’s main window, which it then presents briefly when transitioning your application back to the foreground. Before returning from your applicationDidEnterBackground: method, you should hide or obscure passwords and other sensitive personal information that might be captured as part of the snapshot.
In swift 4 add this code to your app delegate.
Declare a variable in app delegate
var imageview : UIImageView?
func applicationWillResignActive(_ application: UIApplication) {
imageview = UIImageView.init(image: UIImage.init(named: "bg_splash"))
self.window?.addSubview(imageview!)
// Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
// Use this method to pause ongoing tasks, disable timers, and invalidate graphics rendering callbacks. Games should use this method to pause the game.
}
func applicationDidBecomeActive(_ application: UIApplication) {
if (imageview != nil){
imageview?.removeFromSuperview()
imageview = nil
}
// Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
}
You can use this extension below. Please apply this method to the parent view
extension UIView {
func preventScreenshot(for view: UIView) {
let textField = UITextField()
textField.isSecureTextEntry = true
textField.isUserInteractionEnabled = false
guard let hiddenView = textField.layer.sublayers?.first?.delegate as? UIView else {
return
}
hiddenView.subviews.forEach { $0.removeFromSuperview() }
hiddenView.translatesAutoresizingMaskIntoConstraints = false
self.addSubview(hiddenView)
hiddenView.fillSuperview()
hiddenView.addSubview(view)
}
}
So for instance to be able to prevent screenshots on a scrollView
private weak var scrollView: UIScrollView! (it's an outlet)
in your viewDidLoad, just do this below
self.view.preventScreenshot(for: self.scrollView)
Note: fillSuperview is just anchoring your view to its superview so it's like below:
NSLayoutConstraint.activate([
hiddenView.leadingAnchor.constraint(equalTo: self.leadingAnchor),
hiddenView.trailingAnchor.constraint(equalTo: self.trailingAnchor),
hiddenView.bottomAnchor.constraint(equalTo: self.bottomAnchor),
hiddenView.topAnchor.constraint(equalTo: self.topAnchor)
])
fillSuperview? –
Reddin For iOS 17, Swift 4 or Swift 5, those who are getting issue or crash with the previous implementations. Here is a correct way to do it. I just implemented and tested it on iOS 17+.
Add this code in AppDelegate class:
func makeSecure(window: UIWindow) {
let field = UITextField()
let view = UIView(frame: CGRect(x: 0, y: 0, width: field.frame.self.width, height: field.frame.self.height))
let image = UIImageView(image: UIImage(named: "whiteImage"))
image.frame = CGRect(x: 0, y: 0, width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
field.isSecureTextEntry = true
window.addSubview(field)
view.addSubview(image)
window.layer.superlayer?.addSublayer(field.layer)
field.layer.sublayers?.last!.addSublayer(window.layer)
field.leftView = view
field.leftViewMode = .always
}
You can call this from AppDelegate's didFinishLaunchingWithOptions function.
if let window = window {
makeSecure(window: window)
}
This will prevent screen recording as well as ScreenShot in your app.
I've heard that you can listen for a screenshot event using UIApplicationUserDidTakeScreenshotNotification
NSOperationQueue *mainQueue = [NSOperationQueue mainQueue];
[[NSNotificationCenter defaultCenter] addObserverForName:UIApplicationUserDidTakeScreenshotNotification
object:nil
queue:mainQueue
usingBlock:^(NSNotification *note) {
// executes after screenshot
NSLog(@"Screenshot Detection : %@", note);
UIAlertView *screenshotAlert = [[UIAlertView alloc] initWithTitle:@"Screenshot Detected" message:@"Oh Oh no screenshot bruhh" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[screenshotAlert show];
}];
what if you could immediately delete the screenshot file when it was made?
You can prevent screen capture and screen recording of a specific view in your app by using this custom view. Also, you can add your own placeholder that will only show when the user tries to screen capture or screen record.
import Foundation
import UIKit
class SecureView: UIView {
// placeholder will become visible when user try to capture screenshot
// or try to record the screen
private(set) var placeholderView: UIView = {
let view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false
return view
}()
// add your content in this view
// it will be secure
private(set) var contentView: UIView = {
let hiddenView = UIView()
hiddenView.makeSecure()
hiddenView.translatesAutoresizingMaskIntoConstraints = false
return hiddenView
}()
override init(frame: CGRect) {
super.init(frame: frame)
setupView()
}
required init?(coder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
fileprivate func setupView() {
self.addSubview(placeholderView)
self.addSubview(contentView)
NSLayoutConstraint.activate([
placeholderView.leadingAnchor.constraint(equalTo: self.leadingAnchor),
placeholderView.trailingAnchor.constraint(equalTo: self.trailingAnchor),
placeholderView.topAnchor.constraint(equalTo: self.topAnchor),
placeholderView.bottomAnchor.constraint(equalTo: self.bottomAnchor),
contentView.leadingAnchor.constraint(equalTo: self.leadingAnchor),
contentView.trailingAnchor.constraint(equalTo: self.trailingAnchor),
contentView.topAnchor.constraint(equalTo: self.topAnchor),
contentView.bottomAnchor.constraint(equalTo: self.bottomAnchor),
])
}
}
extension UIView {
func makeSecure() {
DispatchQueue.main.async {
let field = UITextField()
field.isSecureTextEntry = true
self.addSubview(field)
field.centerYAnchor.constraint(equalTo: self.centerYAnchor).isActive = true
field.centerXAnchor.constraint(equalTo: self.centerXAnchor).isActive = true
self.layer.superlayer?.addSublayer(field.layer)
field.layer.sublayers?.first?.addSublayer(self.layer)
}
}
}
© 2022 - 2024 — McMap. All rights reserved.
