Owners of smartphones Android 9 Pie often face the need to restrict access to certain applications - be it instant messengers with personal correspondence, banking apps or games that distract from work. Unlike new versions of the OS, where blocking is integrated into the system, in Android 9 this function is either hidden in the depths of the settings or requires the installation of additional tools.

In this article we will examine 5 proven methods blocking an application on Android 9 - from standard tools (for example, Screen PIN code for individual apps) to specialized utilities like AppLock or Norton App Lock. We will pay special attention to methods that work without superuser rights (root), since most users are not ready to risk the warranty for additional functions.

It is important to consider that the effectiveness of blocking depends on the device manufacturer: on “pure” Android (for example, Google Pixel) there is one algorithm, on shells Samsung One UI, Xiaomi MIUI or Huawei EMUI - another. We will indicate the nuances for popular brands.

1. Built-in application blocking (for some manufacturers)

Some branded shells based on Android 9 have their own tools for blocking applications. For example, Xiaomi and Huawei offer this function out of the box, while Samsung or Google Pixel do not. You can check availability like this:

  • 🔍 For Xiaomi (MIUI 10/11): go to Settings → Application lock (section "Privacy"). Here you can set a password or fingerprint to access selected apps.
  • 🔒 For Huawei (EMUI 9): open Settings → Security → Application blocking. The system will prompt you to create a PIN code or pattern.
  • ❌ For Samsung/Google Pixel: There is no built-in function - third-party solutions will be required (see sections below).

If your device supports built-in locking, this method is preferable: it does not require installation of additional apps and has minimal impact on performance. However it has a limitation: blocking is triggered only the first time the application is launched after rebooting or closing from the multitasking menu.

⚠️ Attention: On some firmware (for example MIUI Global), the application blocking function may not be available due to regional restrictions. In this case, changing the region in the settings or installing alternative firmware will help.
Manufacturer Presence of built-in blocking Protection type Restrictions
Xiaomi (MIUI 10/11) ✅ Yes PIN, fingerprint, pattern Does not block notifications
Huawei (EMUI 9) ✅ Yes PIN, password Works only for stock applications
Samsung (One UI 1.0) ❌ No — Requires third-party utilities
Google Pixel (Stock Android 9) ❌ No — You need to install AppLock

2. Using AppLock (the most universal method)

AppLock from DoMobile Lab is one of the most popular solutions for blocking applications on Android 9. The application is free (with advertising), supports all types of protection: PIN code, pattern key, fingerprint (if the sensor is supported by the device). The main advantage is that it works without root access.

To block the application using AppLock:

  1. Download AppLock from Google Play (check that the developer is DoMobile Labto avoid clones).
  2. When you first start, set main password (we recommend using a combination of 6+ characters).
  3. In the main menu, click + Add application and select apps to block from the list.
  4. Activate the option Deletion protection in the settings so that an attacker cannot uninstall AppLock without a password.

The application also allows you to block:

  • 📱 Incoming calls (hiding a number or blocking calls from certain contacts).
  • 🔄 Settings system (for example, so that no one can turn off Wi-Fi or mobile data).
  • 📷 Gallery and files (hiding photos/videos in a separate storage).
⚠️ Attention: Some antiviruses (for example, Avast or Kaspersky) may conflict with AppLock, regarding it as “potentially dangerous software.” This is a false positive - add AppLock to your antivirus exceptions.

Download the official version from Google Play|Create a strong password (at least 6 characters)|Enable deletion protection|Check fingerprint compatibility (if available sensor)-->

3. Locking via "Screen PIN code" (for individual applications)

Some applications (for example, WhatsApp, Telegram, 1Password) have a built-in PIN code screen lock function. This is convenient if you only need to protect 1-2 apps, but don’t want to install a separate one. AppLock I don't want to.

How to enable:

  • 💬 WhatsApp: open Settings → Account → Privacy → Fingerprint/password lock. Set the PIN and activate the option.
  • 📱 Telegram: go to Settings → Privacy and Security → Code blocking. Here you can set a 4-digit password.
  • 🔐 1Password/LastPass: The blocking is activated automatically upon first launch (a master password is set).

The disadvantage of this method is lack of versatility: each application is blocked separately, and not all apps support this function. In addition, the protection only works during cold start (after closing from multitasking).

💡

If you use Nova Launcher or another alternative launcher, check its settings - some support locking application folders via gestures or PIN code.

4. Creating a second user (for complete isolation)

If you need not just to block the application, but completely hide it from strangers, you can use the function Multi-user mode v Android 9. This method is suitable for devices where privacy is important (for example, corporate phones or family tablets).

Instructions:

  1. Open Settings → System → Advanced → Multi-user mode.
  2. Click Add user and follow the instructions (you will be required to provide a name and, if necessary, a password for the new profile).
  3. Switch to the new user (swipe down the notification panel → user icon).
  4. In the new profile do not install applications that you want to hide. They will remain available only in the main account.

Advantages of the method:

  • 🔒 Complete data isolation (applications, files, accounts do not overlap).
  • 📱 No need for third-party apps.
  • 🔄 Quick switching between profiles.

Disadvantages:

  • ⚠️ Applications in the main profile not blocked, but are simply hidden from the second user.
  • 📴 Some functions (for example, calls) may be duplicated.
⚠️ Attention: On devices Samsung with One UI 1.0 multi-user mode may be disabled by the manufacturer. In this case, use Secure Folder (see next section).

5. Secure Folder (for Samsung devices)

Smartphone owners Samsung on Android 9 can use a proprietary solution - Secure Folder. This is an isolated space where you can store applications, files and data protected by a password or biometrics.

How to set it up:

  1. Open Settings → Biometrics and security → Secure Folder.
  2. Log in through your account Samsung (required!).
  3. Set the unlock method: PIN, password or fingerprint.
  4. Click Add applications and select apps from the main menu. They will be duplicated in Secure Folder.

Secure Folder allows:

  • 🔐 Block access to applications even when the screen is unlocked.
  • 📁 Hide files (photos, videos, documents) from the main profile.
  • 🔄 Synchronize data with the cloud Samsung Cloud.

Limitations:

  • ❌ Works only on devices Samsung.
  • 📴 Requires authorization through an account Samsung (functionality without it unavailable).
  • 🔄 Applications in Secure Folder are updated separately from the main ones.

With built-in tools|AppLock|I create a second user|Secure Folder (Samsung)|I don’t block-->

6. Blocking via ADB (for advanced users)

If you are ready to use developer tools, you can block access to applications via ADB (Android Debug Bridge). This method does not require root access, but requires working with the command line.

Instructions:

  1. Activate Developer mode: go to Settings → About phone → Build number and click on it 7 times.
  2. Go back to Settings → System → For developers and enable USB debugging.
  3. Connect your phone to the PC, install ADB drivers and open the command line.
  4. Enter the command to block the application (for example, Facebook): 
    adb shell pm hide com.facebook.katana

    To unblock:

    adb shell pm unhide com.facebook.katana

List of popular packages to block:

Application Package name
WhatsApp com.whatsapp
Instagram com.instagram.android
TikTok com.zhiliaoapp.musically
Google Chrome com.android.chrome

Warnings:

  • ⚠️ After rebooting the device, the lock is reset (you will have to repeat the command).
  • 🔧 Not all system applications can be blocked (for example, com.android.settings).
  • 📱 On some firmware (MIUI, ColorOS) command pm hide may not work.
What to do if ADB does not recognize the device?

If the command adb devices does not show your phone, check:

1. Are the drivers installed (for Windows - Google USB Driver).

2. Is the mode enabled? File transfer (not only "Charging").

3. Have you enabled debugging on the phone (pop-up window when connected).

4. (try a different cable or connector on your PC).

Common errors and how to avoid them

When blocking applications on Android 9 users often encounter typical problems: Here's how to solve them:

  • 🔓 Forgot your AppLock password:

    If you have not linked an email for recovery, the only way is uninstall the application via Safe Mode:

    1. Turn off the phone.
    2. Hold the power button Volume downuntil the logo appears.
    3. Uninstall Safe Mode uninstall AppLock through settings.
  • 📵 Lock does not work after update:

    Update AppLock or reinstall it. If the problem persists, check the settings Accessibility - sometimes blockers conflict with other services.

  • 🔄 The application will unlock itself:

    In the settings AppLock disable the option Auto-unlocking in trusted networks (Wi-Fi/Bluetooth). Also check if the settings are reset after clearing the cache.

    • ⚠️ Attention: If you use Xposed Framework or other system modifications, blockers applications may work unstable. In this case, we recommend rolling back to the standard firmware or using Island (for devices that support Work Profile).
    💡

    The most reliable method of blocking on Android 9 is a combination of AppLock (for most applications) + built-in tools (for instant messengers). Multi-user mode is suitable for complete data isolation, but does not replace a PIN code.

    FAQ: Answers to frequently asked questions

    Is it possible to block system applications (for example, Settings or Phone)?

    Most blockers (including AppLock) cannot restrict access to system applications due to restrictions Android 9. The exception is Secure Folder on Samsung, but it does not block, but hides them in a separate profile.

    To completely block system apps you will need root access and applications like Titanium Backup (but this is risky and voids the warranty).

    Will the blocking work after resetting the phone to factory settings?

    No, all blocker settings (AppLock, Secure Folder etc.) are reset. If you used AppLock, you will have to install and configure it again. synchronization. Secure Folder on Samsung data can be restored through your account Samsung Cloud, if synchronization was enabled.

    Is it possible to block access to notifications from the application?

    Yes, but not all blockers support this. AppLock there is an option Blocking notifications (in the application settings). data-i="283">Blocking notifications

    • Disable notifications manually: Settings → Applications → [Application name] → Notifications → Disable.
    • Use Notification History Eraser (requires Android 11+, on Android 9 works limited).
    How to block an application from a child, but leave access for yourself?

    Best fit:

    1. Multi-user mode (create profile for a child without access to the necessary applications).
    2. AppLock with function Invisible mode (hides the locker icon) + fingerprint for quick unlocking.
    3. Google Family Link (if the child is under 13 years old) - allows you to remotely control access to applications.

      4. We do not recommend relying only on the PIN code - children quickly learn to spy on combinations.

    Is it true that application blockers steal data?

    The vast majority of popular ones blockers (for example, AppLock from DoMobile Lab or Norton App Lock) do not steal data, but:

    • Always download applications only from Google Play (not from third-party sites).
    • Check before installation permissions (the blocker should not request access to SMS, geolocation or contacts for no reason).
    • Use an antivirus (for example, Malwarebytes) to scan installed apps.

      • If in doubt, choose a blocker from a well-known developer (for example, Norton or Avast).