Making changes to an application Android is a task faced by both developers and ordinary users. Some people want to improve the functionality of their project, others want to fix bugs in third-party software, and others are simply experimenting with the interface. But regardless of the goal, the process requires an understanding of technical nuances: from working with source code to publishing updates to Google Play Console.

It is important to consider that modifying applications may violate the terms of use of some services (for example, Google Play Protect blocks modified APKs). In this article, we will look at legal and technically correct ways to make changes - from editing the manifest to reverse engineering (reverse engineering). You will also learn what tools are needed for different tasks and how to avoid mistakes that lead to application crashes or account blocking.

If you are not a developer, but want to change the behavior of the application (for example, remove ads or add a missing function), pay attention to the sections about patch managers and modified APK. For professionals, instructions on working with Android Studio, Gradle and version control systems will be useful.

1. Preparing for changes: what you need to know before you start

Before making changes, determine purpose of modification and its legality. Changing your own application (for example, to add a new feature) is one thing, but editing someone else's software (even if it's free) may violate the license agreement. Be especially careful with closed source applications.

Also check:

  • 📱 Android version: some tools (for example APKTool) require certain OS versions.
  • 🔧 Having root access: for deep changes (modification of system applications) they are required.
  • 📂 Backup: create a backup of the original APK and application data via adb backup or Titanium Backup.
  • 🛠️ Tools: prepare Java JDK, Android SDK, APKTool or JADX (depending on the task).
⚠️ Attention: Modifying system applications (for example com.android.systemui) without root access or through untested patches can lead to k bootloop (loop device loading). On some devices (for example Samsung Knox) this will void the warranty.

If you plan to post changes to Google Play, please consider the privacy policy. For example, adding new permissions (android.permission.READ_CONTACTS) will require updating the file privacy_policy_url in the developer console.

📊 Why do you want to change the application?
Add a new function
Fix a bug
Remove advertising
Experiment with design
Other

2. Method 1: Editing source code in Android Studio

This is the most reliable method for developers who have access to the project sources. It is suitable for:

  • 🆕 Adding new screens (Activity/Fragment).
  • 🔄 Changing the operating logic (for example, sorting algorithm in a list).
  • 🎨 Reworking the interface (themes, animations, fonts).

To make changes:

  1. Open the project in Android Studio (version 2023.2.1 or later).
  2. Find the required file:
    • Application logic - in the folder java/com/your_package/.
    • Interface - in res/layout/ (XML files).
    • Manifest - AndroidManifest.xml.
  • Make edits. For example, to change the button text, edit the line in res/values/strings.xml: 
    New text
  • Build the project (Build → Make Project) and check the changes on the emulator or device.
    • ⚠️ Attention: If you change targetSdkVersion to build.gradle, test the application on all supported versions of Android. For example, switching from targetSdkVersion 30 to 34 may break the work with permissions.

    To speed up the process, use hot reboot (Apply Changes), but remember: it does not work if you change the manifest or resources.

    ☑️ Preparing to build APK

    Done: 0 / 4

    3. Method 2: Modifying APK without source code

    If you do not have the source code, but need to change the behavior of the application, use decompilation i recompilation APK. This method is suitable for:

    • 🚫 Removing ads (blocking AdMob or Facebook Audience Network).
    • 🔓 Unlocking premium features (if any are checked on the client side).
    • 📱 Changes in supported screen resolutions.

    Popular tools:

    Tool Purpose Complexity
    APKTool Decompile/recompile APK, edit resources and manifest Medium
    JADX View decompiled code (Java) Low
    Smali/Baksmali Bytecode editing (for experienced) High
    Lucky Patcher Automatic APK patching (requires root) Low

    Example of working with APKTool:

    1. Decompile APK: 
      apktool d your_application.apk -o output_folder
    2. Edit files in the folder output_folder. For example, to remove ads, find in smali classes mentioned com/google/ads and replace them on nop (no operation).
    3. Rebuild the APK: 
      apktool b output_folder -o patched.apk
    4. Sign the APK (use uber-apk-signer or jarsigner).
    What happens if you do not sign the APK?

    An unsigned APK will not be installed on the device. Android requires a digital signature to verify the integrity of the file. If you have changed the original APK, its signature will become invalid and the system will block the installation with the error "Parse Error".

    Changed APKs may not pass Google Play Protect verification. To avoid automatic removal, add the application to exclusions or disable scanning (not recommended for security reasons).

    4. Method 3: Using Xposed Framework and LSPosed

    If you need to change the behavior of the application without editing the APK, use modules for Xposed or its modern analogue - LSPosed. This method works at the system level and allows you to:

    • 🔄 Intercept method calls (for example, block ad impressions).
    • 🎭 Change the appearance of interface elements.
    • 🔒 Bypass some checks licenses.

    Instructions for LSPosed:

    1. Install LSPosed (required Magisk or another root manager).
    2. Download the module for your task. Popular:
      • GravityBox — interface customization.
      • AdAway — ad blocking at the system level.
      • App Settings — changing DPI or permissions for individual applications.
  • Activate the module in LSPosed and reboot device.
  • Configure rules for the target application (for example, add ad network domains to the blacklist).
    • ⚠️ Attention: Some Xposed/LSPosed modules conflict with SafetyNet, which may cause banking applications or Google Payto stop working. Before installation, check compatibility on the forum XDA Developers.

    The advantage of this method is No need to rewrite the APKchanges are applied dynamically. However, it requires root access and can reduce system stability.

    💡

    If the application crashes after installing the module, check the logs via logcat. A common mistake is a conflict between library versions. Try rolling back the module or updating it.

    5. Method 4: Updating the application via Google Play Console

    If you are a developer and want to publish changes to users, use Google Play Console. This process includes:

    1. Preparation of release:
      • Increase versionCode and versionName in build.gradle.
      • Generate signed App Bundle (Bundletool or Android Studio).
      • Update screenshots and description if functionality has changed.
    2. Upload to console:
      • Go to section Production → Create new release.
      • Upload .aabfile.
      • Fill out the release notice (what's new in the version).
  • Verification and publication:
    • Google will check the application for compliance with policies (usually takes 1-3 days).
    • After approval, click Start rollout.

    Important nuances:

    • 📦 App Bundle (.aab) is required for new applications from August 2021. It optimizes the download size for users.
    • 🔍 Pre-test: Use internal testing or closed testingto test the update on a small group of users.
    • 📉 Gradual rollout: Set up a phased distribution (for example, 10% of users in day) to quickly roll back the update in case of bugs.
    💡

    Use tags android:versionCode and android:versionName in the manifest correctly: versionCode should always be incremented (integer), and versionName should be displayed to users (for example, "2.1.0").

    6. Method 5: Patching applications using Magisk and modules

    For advanced users with root access, this method is suitable Magisk modules. It allows you to make changes to system and user applications without editing the APK. Popular scenarios:

    • 🔓 Unlocking functions in games (for example, Magisk Module for Spotify Premium).
    • 📱 Changing system fonts or animations.
    • 🚀 Performance optimization (for example, disabling unnecessary services).

    How to create your own module:

    1. Copy the files that need to be replaced (for example, from /system/priv-app/).
    2. Create a module structure: 
      magisk_module/

      ├── customize.sh
      

      ├── module.prop
      

      ├── system/
      

      │ └── priv-app/
      

      │ └── your_application/
      

      └── README.md

    3. Edit module.prop: 
      id=your_module

      name=Module name
      

      version=1.0
      

      versionCode=1
      

      author=Your name
      

      description=Description changes

    4. Add the installation script to customize.sh (if you need to execute commands upon activation).
    5. Go to Magisk Manager, select Modules → Install from storage and reboot the device.
    ⚠️ Attention: Some Magisk modules may break SafetyNetwhich will lead to problems with Netflix, Pokémon GO or banking applications. To check the status, use SafetyNet Test from MagiskHide Props Config.

    Ready-made modules can be found at GitHub or forums like XDA. For example, the module Universal SafetyNet Fix helps bypass system integrity checks.

    7. Risks and how to avoid them. data-i="235">Making changes to applications is fraught with consequences - from crashing the app to blocking your Google account. Main risks:

    Making changes to applications is fraught with consequences - from crashing the app to blocking your Google account. Main risks:

    Risk Cause How to avoid
    Blocking Google Play Protect The modified APK is recognized as malicious Disable device scanning or add the application to exceptions
    Data loss Incompatibility of the new version with the database Make a backup via adb backup or Swift Backup
    Ban an account in the game Use of a modified client (for example, in PUBG Mobile) Do not change online games or use alternative accounts
    Bootloop Incorrect modification of system APK Test changes on custom recovery (TWRP)

    To minimize problems:

    • 🔍 Test changes on emulator or secondary device.
    • 📋 Keep a log of changes (what was modified and why).
    • 🔄 Use a version control system (Git) to roll back to the working version.
    • 🛡️ For critical applications (banks, instant messengers) avoid modifications.

    Decompiling and repackaging APK may violate licensing agreements (for example, GNU GPL requires publication of the source code of modified versions.

    8. Alternative methods: when you do not need to change the APK

    Sometimes the goal can be achieved without editing the application:

    • 🤖 Automation tools: Use Tasker or MacroDroid to automate actions in application (for example, skipping advertising by clicking on coordinates).
    • 🌐 Proxy servers: To block ads or change the server response (for example, Charles Proxy or Fiddler).
    • 📱 ADB commands: Some settings can be changed via adb shell. For example, disable animations: 
      adb shell settings put global window_animation_scale 0

      adb shell settings put global transition_animation_scale 0

    • 🔄 Alternative clients: For example, instead of modification YouTube use Vanced or ReVanced.

    These methods are less are risky since they do not affect the APK itself. For example, ReVanced offers patched versions of popular open source applications, which is safer than decompiling it yourself.

    💡

    Before using alternative clients, check their reputation on GitHub or XDA. Some "modified" APKs contain malware.

    FAQ: Frequently asked questions

    Is it possible to change a system application without root?

    No, to modify applications in /system/priv-app/ root access is required. Without them, you can only:

    • Disable the application via Settings → Applications (not on all devices).
    • Use ADB to disable packages (adb shell pm disable-user --user 0 com.android.application).

    On some firmware (for example, LineageOS), system applications can be updated via Magisk without full access to /system.

    How to check if it will break application after changes?

    Use the following tools:

    • Emulator: Android Studio Emulator or Genymotion.
    • Logs: adb logcat grep | your_package to track errors.
    • UI testing: UI Automator to test the interface.

    If the application crashes, check AndroidManifest.xml for the correct permissions and SDK versions.

    What to do if Google Play Protect deletes my modified application?

    Solution options:

    1. Add the application to exceptions Play Protect (in security settings).
    2. Disable Play Protect completely (not recommended).
    3. Rebuild the APK with a different certificate (but this may break work with Google Services).
    4. Use alternative stores (for example, APKMirror or F-Droid).

    Please note that disabling Play Protect reduces protection against malware Software.

    Is it possible to update a modified application via Google Play?

    No, if you modified the original APK, its signature will not match the signature of the update from Google Play. Options:

    • Remove the modified version and install the original, then update.
    • Manually patch each update (labor-intensive).
    • Use App Cloner to create a separate copy of the application.
    How to return the original application if it does not work after changes?

    Rollback methods:

    1. Delete the application and install the original APK (download from APKMirror).
    2. Restore the backup via adb restore or Titanium Backup.
    3. For system applications, reset via TWRP or reflash stock ROM.

    If the application was previously installed (for example, Gmail on Pixel), it can be updated via Google Playto return the original version.