Google’s Android 14 developer documentation explains that apps which do not want their activity contents to appear in screenshots or on non-secure displays can set the `FLAG_SECURE` display flag. The docs state: "If you don't want the contents of an app's activity to appear in screenshots, or on non-secure displays, set the FLAG_SECURE display flag." It also notes that Android 14 introduces a privacy-preserving screenshot detection API, but to *block* screenshots, the prescribed mechanism is `activity.getWindow().setFlags(LayoutParams.FLAG_SECURE, LayoutParams.FLAG_SECURE)`. This is the same flag that the Dunkin’ Android tech stack page reports the app as using.

Under the "Security" section for the Dunkin’ Android app, this tech stack analysis states: "Implements root detection, Android Keystore, biometric auth, and **FLAG_SECURE to block screenshots and recordings**." It further lists "Screenshot/recording block (FLAG_SECURE)" among the security-related technologies used in the app, indicating that the Android client is configured to prevent screen capture.

A technical journal article discussing screenshot and screen-capture behavior on iOS notes that, unlike Android’s ability to mark a screen so it cannot be captured at all, iOS does not allow apps to block screenshots directly. The author writes: "On Android you can mark a screen so it cannot be captured at all. iOS has no direct equivalent… For screenshots, a screenshot notification fires after the user takes one, so you can respond, log it, warn, or obscure content afterward, but you cannot block the screenshot." This establishes that any iOS "screenshot shield" would be reactive (detection/obscuring) rather than a true prevention mechanism, and that the platform itself does not support fully preventing screenshots the way Android’s FLAG_SECURE does.

The video demonstrates that some Android and iOS apps can block screenshots or make them appear as a black screen, and shows how developers can "ensure all screenshots and screen recordings appear as a black screen" using an SDK function (Talsec.blockScreenCapture()). It explains that this kind of protection is implemented at the app level, not by the user, and is commonly used in finance or security-focused apps.

Luckily, the Android system provides a built-in mechanism for blocking screenshots which is available from Android Honeycomb (3.0). It literally takes one line of code to put in Activity which you’d like to prevent to be screenshotted, and it totally disables this functionality (instead of a screenshot, the user will see the nice error message). Additionally, it blocks all the screen recording options (only black screen is visible as the output) which is a really great add-on. ... For Android, the solution is super simple — just add a single line of code and *Bob’s your uncle.* For iOS — it all depends. If you need 100% protection against screenshots, just use *ScreenShieldKit* — it does its job flawlessly and implementing (and maintaining) similar solution from the scratch will still cost you more than buying a license for sure.

Apps use a specific API to detect screen captures. Android 14 introduced this screenshot feature for privacy. You cannot disable this globally in settings. Some apps might have their own toggles. Look at the specific app permissions for a toggle. ... The most effective workaround right now is to screenshot outside the app (e.g., from the recent apps view or using a slight delay), though that's not always practical.

ScreenShieldKit describes itself as a toolkit to "protect your app from screenshots" and other capture methods in iOS apps. It explains: "Privacy and security are critical for modern apps, and while iOS offers developers many robust security technologies, it doesn’t offer any methods to easily prevent screenshots of your app. That’s why we created ScreenShieldKit — the product of extensive research & development that effectively protects sensitive content in iOS apps from all screen capture methods, including screenshots." This shows the technical concept of a "screenshot shield" for iOS and confirms that iOS itself does not natively block screenshots, requiring app-side solutions.

In a 2013 promotional release, Dunkin’ Donuts encouraged users to take screenshots within the Dunkin’ App as part of a Twitter sweepstakes: "Followers of @DunkinDonuts on Twitter are asked to visit the Dunkin’ App and locate their favorite Dunkin’ Donuts restaurant in the app’s ‘Store Locator’ function. Fans who take a screenshot of this or a picture of their favorite Dunkin’ Donuts location and tweet it to @DunkinDonuts… are eligible to win a $10 mGift." This shows that at least earlier versions of the Dunkin’ app did not prevent screenshots and even used them in promotions, although it does not speak to the current app’s behavior.

An iOS developer explains that "UIKit has a neat trick: if you set a text field’s isSecureTextEntry to true, iOS automatically prevents it from being included in screenshots and system snapshots." This is described as an advanced screenshot prevention technique "inspired by banking authenticator apps," used to hide sensitive UI elements from screenshots by marking them as secure content.

A mobile security practitioner describes a method to "detect and block screenshots in iOS apps" by adding "a tiny secure UITextField" to screens that need protection. Because "secure text fields automatically block screenshots," this trick "prevents the entire screen from being captured" so that "whenever user tries to take a screenshot or tries to do screen recording they will get a blank screen instead of content on the UI." The post states that "by embedding this field invisibly across all views, the app blocks screenshots globally."

In a Reddit discussion titled "Pay with screenshot?" about using the Dunkin’ app, one user warns: "Just be cautious— they can retain the screenshot and continue using it if they wish." The thread discusses the practice of taking a screenshot of the payment barcode/QR code in the Dunkin’ app and using that image to pay, implying that at least at that time the app allowed screenshots of the payment screen without technical blocking.

A Q&A thread on iOS development states: "There's no way to prevent taking screenshots entirely" via public APIs. It notes that apps like Snapchat can reduce screenshotting by requiring a touch for viewing, because "the system screenshot event interrupts touches," but emphasises "you can't prevent users from taking screenshots 100% of the time" at the OS level on iOS. This highlights that iOS does not provide a full screenshot shield like Android's FLAG_SECURE.

In a YouTube walkthrough explaining how to keep using Dunkin’ Donuts app features during iOS beta issues, the presenter says: "I’m loading into my account my Dunkin Donuts account and **taking a screenshot of the app** ... and then keeping it on my phone so I can make a payment." He further notes, "if you ever want somebody else [to] use your Dunkin Donuts app you can do this, just open up the Dunkin Donuts app, **take a screenshot**, send it to them in a text and they can pay for your coffee." This indicates that the iOS version of the Dunkin’ app at that time did not prevent screenshots of the payment barcode.

On the Dunkin’ app listing page (Czech locale) on Google Play, the contact section lists developer/support emails and a phone number but does not mention screenshot blocking or FLAG_SECURE in the public description. The presence of "shield" text appears to relate to the standard Google Play UI (such as privacy or data safety) rather than a named "Screenshot Shield" feature, and there is no explicit note that users are prevented from taking screenshots.

The Italian-language Dunkin’ app page on Google Play provides support contact details and developer information but similarly does not advertise any "screenshot shield" or screenshot-blocking feature in the user-facing description. The listing focuses on ordering, paying, rewards, and account features, without stating that the app prevents users from capturing the screen.

This tutorial targeted at general users shows various ways to take screenshots "when an app blocks them" on smartphones. It acknowledges that "some Android phones have a built-in screen recorder" and suggests recording the screen and extracting frames, using Google Assistant / digital assistants to capture a screen even when normal screenshot shortcuts are blocked, or using a second physical device to photograph the display. The existence of these workarounds implies that certain apps do actively prevent or restrict screenshots on both Android and iOS.

Android’s `FLAG_SECURE` window flag is documented by Google as a way for apps to prevent their content from appearing in screenshots or in the system’s recent apps view. When this flag is set on a window, "the content of the window cannot be captured" by screenshots or screen recording tools. This is the standard mechanism app developers use when they want to implement a screenshot shield on Android.

A troubleshooting article for iPhone users discusses cases where "you can’t take screenshots on iPhone or iPad" and advises checking per-app settings: "Tap the app name. Enable the switch for Allow Screen Recording if you see it." It also notes that Guided Access and some device management profiles can block screenshots on certain screens, showing that screenshot blocking can be app- or policy-specific rather than a universal phone limitation.

DUNKIN' – Apps on Google Play Package name: com.dunkind.app Customer support: customerservice@ddstores.co.uk (No mention in the public description of screenshot restrictions or a screenshot shield feature; typical Play Store listing does not document use of FLAG_SECURE or other screenshot-blocking mechanisms.)

A consumer-focused tutorial video titled "How To Fix This App Doesn't Allow Screenshots!" explains that some apps show a message like "This app doesn't allow screenshots" and refuse capture. It suggests workarounds such as using Google Assistant/Bixby to take a screenshot, using third-party screen recorders that may bypass certain restrictions, or taking a photo of the screen with another device. This demonstrates that per-app screenshot blocking exists and is commonly encountered by users.

A general iOS troubleshooting guide notes that some apps have a specific setting under iOS Settings → Apps where you can toggle "Allow Screen Recording" for that app. It implies that if this is off or if a management profile restricts screen capture, screenshots of that app may fail. The article lists other causes like Guided Access mode that temporarily disable screenshots system-wide, again showing that screenshot blocking can be enforced per app or via device policies.

This iOS security feature description from a mobile security vendor explains a "Block Screenshots" privacy feature for iOS applications that "blurs the app’s screen when it is minimized and viewed in the multitasking switcher." While focused on multitasking previews rather than live screenshots, it shows that some SDKs offer iOS developers mechanisms to hide or obfuscate app content from system-level captures, similar in intent to screenshot shields.

A Reddit discussion on r/iphone asks "How do I take a screenshot on apps that block them!" and users propose workarounds like mirroring the screen to another device, using Google Assistant or Siri to trigger a screenshot, or photographing the display with a second phone. The thread assumes that certain apps (often banking or ticket apps) intentionally block screenshots, but does not specify Dunkin' by name.