APE-4296 | Android webview test app (#2)

#  Token.io Android WebView SDK Demo Application

  ## 📋 Overview

This PR introduces a comprehensive Android demo application showcasing
the Token.io WebView SDK
integration for secure payment processing. The application demonstrates
best practices for payment
flow handling with robust WebView implementation and multi-regional
support.

  ## ✨ Key Features

  ### 🌐 WebView Payment Integration
- **Secure WebView Implementation**: Custom `UnifiedWebViewClient` for
handling payment redirects
- **Dual Callback Support**: Handles payment callbacks from both in-app
WebView and external
  browsers
  - **Payment Flow Activities**:
    - `PaymentWebViewActivity` - Main payment interface
    - `PaymentResultActivity` - Payment outcome display
    - `WebViewActivity` - General web content handling

  ### 🇫🇷 France Market Support
- **Locale-aware Amount Formatting**: Prevents locale-specific decimal
separator issues (e.g.,
  French comma vs English decimal point)
  - **Multi-currency Support**: EUR and GBP payment processing
- **Localized Payment Experience**: Proper handling of French banking
redirects and callbacks

  ### 🛡️ Security & Configuration
- **API Key Management**: Secure BuildConfig integration with
placeholder system
- **Environment Configuration**: Beta environment setup with
configurable endpoints
- **Deep Link Security**: Proper intent filter configuration for payment
callbacks

  ## 🏗️ Technical Implementation

  ### Core Components
  - **PaymentSdk**: Main SDK interface with simplified integration API
- **PaymentRepository**: Network layer for payment operations using
Retrofit + Moshi
  - **Constants**: Environment and configuration management
  - **Data Models**: Type-safe payment request/response handling

  ### WebView Architecture
  Unified callback handling for all payment scenarios:
UnifiedWebViewClient -> PaymentWebViewActivity -> PaymentResultActivity
                    ↓
External Browser Redirect -> MainActivity (Deep Link) ->
PaymentResultActivity

  ### Payment Flow
1. **Initiation**: Create PaymentRequest with creditor details and
amount
2. **WebView Launch**: Secure payment interface with bank redirect
handling
3. **Callback Processing**: Unified handling regardless of redirect
method
4. **Result Display**: Clear payment outcome with appropriate messaging

  ## 🔧 Configuration

  ### Manifest Setup
  - Deep link configuration for `paymentdemoapp://payment-complete`
  - Activity declarations with proper launch modes
  - Intent filter on MainActivity for external callback handling

  ### Build Configuration
  - KSP for Moshi code generation
  - Firebase integration for analytics and user onboarding
  - Comprehensive dependency management

  ## 📱 User Experience

  - **Intuitive Interface**: Clean material design with form validation
  - **Error Handling**: Comprehensive error states and user feedback
  - **Loading States**: Progress indicators during payment processing
  - **Accessibility**: Proper content descriptions and navigation

  ## 🔄 Git Repository Cleanup

- **Comprehensive .gitignore**: Excludes build artifacts, IDE files, and
APK outputs
- **Security**: API keys replaced with placeholders for safe version
control
- **Clean History**: Removed accidentally committed build files and IDE
configurations

  ## 🌍 Market Readiness

  This implementation is production-ready for:
  - **UK Market**: Faster Payments integration
  - **French Market**: SEPA payment support with proper locale handling
  - **Multi-currency**: GBP and EUR support with accurate formatting
  ---

  **🔗 Related Issues**: APE-4296
**📊 Testing**: Manual testing completed for both WebView and browser
redirect scenarios
**🎯 Target**: UK and EU including France market deployment with WebView
payment integration

---------

Co-authored-by: Sam French <150862015+samfrench27@users.noreply.github.com>

Author: embashgit

.gitignore

@@ -0,0 +1,100 @@
+# Built application files
+*.apk
+*.aar
+*.ap_
+*.aab
+
+# APK output directory
+APK/
+
+# Files for the ART/Dalvik VM
+*.dex
+
+# Java class files
+*.class
+
+# Generated files
+bin/
+gen/
+out/
+#  Uncomment the following line in case you need and you don't have the release build type files in your app
+# release/
+
+# Gradle files
+.gradle/
+build/
+
+# Local configuration file (sdk path, etc)
+local.properties
+
+# Proguard folder generated by Eclipse
+proguard/
+
+# Log Files
+*.log
+
+# Android Studio Navigation editor temp files
+.navigation/
+
+# Android Studio captures folder
+captures/
+
+# IntelliJ
+*.iml
+.idea/workspace.xml
+.idea/tasks.xml
+.idea/gradle.xml
+.idea/assetWizardSettings.xml
+.idea/dictionaries
+.idea/libraries
+.idea/jarRepositories.xml
+# Android Studio 3 in .gitignore file.
+.idea/caches
+.idea/modules.xml
+# Comment next line if keeping position of elements in Navigation Editor is desired
+.idea/navEditor.xml
+.idea/misc.xml
+.idea/studiobot.xml
+
+# Keystore files
+# Uncomment the following lines if you do not want to check your keystore files in.
+#*.jks
+#*.keystore
+
+# External native build folder generated in Android Studio 2.2 and later
+.externalNativeBuild
+.cxx/
+
+# Google Services (e.g. APIs or Firebase)
+# google-services.json
+
+# Freeline
+freeline.py
+freeline/
+freeline_project_description.json
+
+# fastlane
+fastlane/report.xml
+fastlane/Preview.html
+fastlane/screenshots
+fastlane/test_output
+fastlane/readme.md
+
+# Version control
+vcs.xml
+
+# lint
+lint/intermediates/
+lint/generated/
+lint/outputs/
+lint/tmp/
+# lint/reports/
+
+# Android Profiling
+*.hprof
+
+# macOS
+.DS_Store
+
+# Sensitive information
+# gradle.properties - committed with placeholder values