FileLocker

An Android file management application that allows users to browse, scan, and organize files on their device's storage with password protection.

Overview

FileLocker is a simple Android file browser that provides:

• Password-protected access to the application
• File system navigation with folder browsing
• File type detection and categorization
• Scanning for specific file types (images, PDFs)
• Thumbnail generation for image files

Features

• Password Protection: Create and manage a password to secure the app
• File Browsing: Navigate through device storage and SD cards
• File Type Detection: Automatically identifies file types based on file headers
• Media Scanning: Quick scan for images and PDF files across storage
• Thumbnail Preview: Generate and display thumbnails for image files
• Multiple Storage Support: Detects and browses multiple storage locations

Requirements

• Android SDK 23 (Android 6.0 Marshmallow)
• Minimum SDK: 15 (Android 4.0.3 Ice Cream Sandwich)
• Target SDK: 23 (Android 6.0 Marshmallow)
• Java

Installation

1. Clone the repository:

   git clone https://github.com/mhan8796/fileLocker.git
   cd fileLocker

2. Build the project using Gradle:

   ./gradlew build

3. Install on an Android device or emulator:

   ./gradlew installDebug

Usage

1. First Launch: Create a password when prompted
2. Subsequent Launches: Enter your password to access the app
3. Menu Options:
   • All files: Browse the complete file system
   • Image: Scan and view all image files
   • PDF: Scan and view all PDF files
4. Navigation: Use the back button in the action bar to navigate up the directory tree

Project Structure

app/src/main/java/com/example/guohuan/filelocker/
├── MainActivity.java          # Login/Password entry point
├── menuActivity.java           # Main menu with file type options
├── fileSystem.java             # File browser implementation
├── scanfileActivity.java      # Activity for scanned file results
├── scanAs.java                 # Background file scanning logic
├── MyDbHelper.java             # SQLite database helper for password storage
├── fileType.java               # File type detection using file headers
├── method.java                 # Utility methods for image processing
└── loadImageFileAs.java        # Async image loading for thumbnails

Permissions

The app requires the following permissions:

• INTERNET - Network access
• ACCESS_WIFI_STATE - WiFi state information
• MOUNT_UNMOUNT_FILESYSTEMS - File system mounting
• ACCESS_NETWORK_STATE - Network state information
• READ_EXTERNAL_STORAGE - Read files from external storage
• WRITE_EXTERNAL_STORAGE - Write files to external storage
• GET_ACCOUNTS - Access user accounts
• READ_PROFILE - Read user profile
• READ_CONTACTS - Read contacts

Known Issues

See the Issues section below for a comprehensive list of problems and areas for improvement.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is provided as-is for educational purposes.

Author

Mingrui Han - mhan8796@gmail.com

Issues

Critical Security Issues

1. Plain Text Password Storage: Passwords are stored in plain text in SQLite database without encryption or hashing
2. SQL Injection Vulnerability: Raw SQL queries are used instead of prepared statements
3. Dangerous Runtime Execution: Uses Runtime.exec("mount") which could be exploited
4. Excessive Permissions: Requests unnecessary permissions (GET_ACCOUNTS, READ_CONTACTS, READ_PROFILE) unrelated to core functionality

Deprecated and Outdated Dependencies

5. Obsolete Android SDK: Uses SDK 23 (Android 6.0, released 2015) - severely outdated
6. Deprecated Support Library: Uses com.android.support:appcompat-v7:23.1.0 instead of AndroidX
7. Deprecated Gradle Plugin: Uses Gradle plugin 1.3.0 instead of modern versions
8. Deprecated jcenter Repository: jcenter has been shut down and should be replaced with Maven Central
9. Deprecated AsyncTask: Uses AsyncTask which is deprecated in API 30
10. Deprecated getDrawable(): Uses deprecated getDrawable() method instead of ContextCompat.getDrawable()

Code Quality Issues

11. No Actual File Locking: Despite the name "FileLocker", the app doesn't actually lock or encrypt files
12. Memory Leaks: Bitmap arrays stored in memory without proper cleanup
13. Poor Lifecycle Management: No proper handling of Activity lifecycle events
14. Inconsistent Error Handling: Empty catch blocks and silent failures throughout
15. Hardcoded Package Name: Uses com.example.guohuan.filelocker which should be changed for production
16. Deprecated Stack Usage: Uses Stack instead of modern Deque implementations
17. Magic Numbers: Hardcoded values like REQUIRED_SIZE = 70 without explanation
18. Code Duplication: Similar adapter logic duplicated across multiple activities
19. Missing Null Checks: Insufficient null checks before file operations
20. No Input Validation: Password field lacks complexity requirements or validation

Performance Issues

21. Inefficient Image Loading: Loads full images before scaling instead of using proper sampling
22. Blocking UI Operations: File scanning on main thread could cause ANRs
23. No Caching: Thumbnails are not cached, causing repeated loading
24. Inefficient File Scanning: Recursive scanning without optimization for large directories

Functionality Issues

25. Incomplete File Type Support: Limited file type detection (mainly images and PDFs)
26. No File Operations: Cannot open, delete, move, or share files
27. No Search Functionality: No way to search for specific files
28. Broken Navigation: Back button logic is complex and potentially buggy
29. No Settings: No way to change password or configure app settings
30. No Help/Documentation: No in-app help or user guidance

Build and Configuration Issues

31. Outdated Build Tools: Uses buildToolsVersion "23.0.2"
32. No ProGuard Rules: ProGuard is disabled in release builds
33. Missing Version Control: No .gitignore for sensitive files
34. No CI/CD: No automated testing or deployment configuration
35. No Dependency Management: No lockfile for Gradle dependencies

Testing and Quality Assurance

36. No Unit Tests: No test coverage for any components
37. No Integration Tests: No testing of user flows
38. No UI Tests: No automated UI testing
39. Manual Testing Only: Relies entirely on manual testing

Accessibility and Localization

40. No Accessibility Support: No content descriptions for screen readers
41. English Only: No localization support for other languages
42. Poor UI Contrast: No consideration for color blindness or visual impairments

Documentation

43. No README Existed: No documentation before this review
44. No Code Comments: Minimal inline documentation
45. No API Documentation: No documentation for public methods
46. No Architecture Documentation: No explanation of app architecture or design patterns

Recommendations for Improvement

Immediate Actions:

• Migrate to AndroidX and modern Android SDK (API 33+)
• Implement proper password hashing (bcrypt, PBKDF2, or Argon2)
• Replace raw SQL with Room database or prepared statements
• Remove unnecessary permissions
• Add proper encryption for actual file locking functionality

Short-term Improvements:

• Implement proper lifecycle management
• Add error handling and user feedback
• Add file operations (open, delete, share)
• Implement search functionality
• Add caching for thumbnails

Long-term Improvements:

• Complete rewrite using modern Android architecture (MVVM, Kotlin, Jetpack Compose)
• Implement comprehensive testing suite
• Add accessibility features
• Support for cloud storage integration
• Implement biometric authentication