Android Portfolio: My Portfolio
Skills Overview
Programming Languages: Kotlin, Java
Declarative UI: Jetpack Compose, AndroidX XML
Dependency Injection: Hilt, Dagger2, Koin
Database: Room, SQLite
Third-Party Services: Facebook, AWS, Google MLKit, Huawei, Line Bot API, Samsung, FCM, Huawei Push Kit, etc.
Asynchronous Programming: Thread, AsyncTask, Coroutine
Flow Control: RxJava, Kotlin Flow
Network & IPC: OkHttp, Retrofit, Socket, AIDL
Android Device Control: Device Owner, Knox, Accessibility
Version Control: Git
Tools: adb, aapt, jd-gui, dex2jar, apktool, jekyll
Architecture: Android, MVVM
Hello everyone, I'm an experienced Android developer proficient in Kotlin and Java.
Today, I'd like to share some of my past works and experiences.
My portfolio showcases a variety of apps.
Feel free to contact me for more information. Thank you for watching!
App Portfolio
9 / 9 ProjectsAI Chat Assistant (ChatInsight.AI)
AI chat app supporting mainstream LLM models, internal enterprise AI bots, workflows, model switching, and group chats.
Key Responsibilities & Highlights
- Built 100% in Kotlin with modern Jetpack Compose for declarative UI and fluid animations.
- Adopted Navigation-Compose to construct a clean single-activity navigation architecture.
- Integrated mainstream LLM model APIs with real-time AI thinking streaming and Markdown rendering.
- Implemented session history management, internal enterprise AI bot exploration, and dynamic model switching.
- Integrated backend RESTful APIs and AWS S3 storage with production telemetry and debugging tools.
Engineering Architecture & Technical HighlightsExpand ▾
Modern Declarative UI with Jetpack Compose
Constructed using 100% Kotlin with Jetpack Compose and Navigation-Compose in a single-activity architecture, completely decoupling UI state from business logic.
Asynchronous Streaming & Instant Rendering
Leveraged Coroutines and Kotlin Flow to consume Server-Sent Events (SSE), delivering typewriter token streaming and minimizing perceived latency.
Enterprise Bot & Knowledge Base Integration
Connected backend REST APIs with AWS S3 storage, facilitating department-specific knowledge retrieval, session persistence, and offline caching.
Performance Monitoring & Recomposition Optimization
Implemented global exception handlers and embedded vConsole diagnostics, optimizing long chat list recomposition to prevent jank and crashes.
AirDroid Kid Browser app
Dedicated safe browser application designed for children and teens, featuring real-time URL black/whitelist filtering, parental monitoring, and history tracking.
Key Responsibilities & Highlights
- Researched and evaluated Android browser core implementation strategies prior to project kickoff.
- Implemented custom requirement screens and UI widgets 100% in Kotlin.
- Engineered cross-app binding, parental authorization workflows, history tracking, and token refresh.
- Integrated backend APIs using OkHttp and Retrofit for resilient bidirectional communication.
- Led maintenance, release upgrades, and bug fixes.
Engineering Architecture & Technical HighlightsExpand ▾
Android WebView Core Architecture
Researched Android WebView rendering architecture, implementing customized WebViewClient and WebChromeClient for smooth page rendering and request interception.
Cross-App Identity & Token Refresh
Engineered secure IPC with the parent supervisor app, verifying signatures and automatically renewing tokens without disrupting child browsing.
High-Performance URL Interception
Utilized localized Trie-tree caching and regex patterns inside shouldInterceptRequest to achieve near-zero-latency policy enforcement.
Retrofit & OkHttp Network Layer
Encapsulated network interceptors, telemetry loggers, and offline queuing to ensure reliable logging under weak network conditions.
AirDroid Remote Support app
Enterprise cross-device remote assistance solution featuring 9-digit code instant connections, AR 3D marker guidance, unattended remote management, and custom input plugins.
Key Responsibilities & Highlights
- Maintained core app and led new feature module development.
- Built QR code generation, scanning, onboarding tutorials, enterprise binding, attended/unattended mode switching, and permissions from scratch.
- Integrated backend APIs and maintained low-latency bidirectional WebSocket connection.
- Authored all new features in Kotlin for clean code and heightened reliability.
- Integrated proprietary helper plugin, guided installations, and built-in keyboard (InputMethodService) mapping.
- Upgraded build system dependencies to Gradle Version Catalogs (libs.versions.toml).
Engineering Architecture & Technical HighlightsExpand ▾
Persistent Signaling & Real-time Connectivity
Maintained WebSocket heartbeat and automatic reconnection to transmit remote control signals within milliseconds.
Custom InputMethodService Plugin Architecture
Engineered plugin installation flow and utilized Android InputMethodService for cross-platform keyboard mapping and shortcut injection.
Dual Mode Switching & Security Enforcement
Dynamically adjusted permission prompts based on security policies, leveraging Accessibility Services for continuous unattended standby.
Gradle Dependency Modernization
Migrated legacy multi-module dependencies to modern Gradle Version Catalogs (libs.versions.toml) for standardized dependency management.
AirDroid Business - Enterprise MDM App
Enterprise mobile device management (MDM/EMM) client offering Device Owner deep policies, Samsung Knox API integration, single-app Kiosk lockdown, and configuration provisioning.
Key Responsibilities & Highlights
- Maintained enterprise app and supported continuous MDM feature evolution.
- Built robust enterprise-grade UI components and system management screens.
- Researched and implemented device policy management features.
- Integrated Samsung Knox SDK for hardware-level enterprise controls.
Engineering Architecture & Technical HighlightsExpand ▾
Samsung Knox SDK Integration
Integrated Knox Enterprise License (KLM/ELM) activation workflows to unlock deep hardware restrictions on Samsung enterprise devices.
Android Enterprise Privileged Architecture
Followed Android Enterprise standards, provisioning Device Owner status via NFC/DPC for rootless enterprise governance.
Background Services & Keep-Alive Watchdog
Combined Foreground Services with JobScheduler to withstand aggressive OEM battery optimizers and guarantee prompt command execution.
AirDroid Kids - Parental Control App
Child protection and supervision client featuring geofence alerts, scheduled screen time limits, app blocking, and alert notifications.
Key Responsibilities & Highlights
- Maintained client app stability across diverse Android versions and screen sizes.
- Built responsive UI views matching comprehensive design specifications.
- Refactored the primary 'My Page' profile and child settings screens.
- Resolved UI display defects and fixed historical layout rendering bugs.
Engineering Architecture & Technical HighlightsExpand ▾
Profile & Settings Screen Modernization
Refactored legacy nested layout hierarchies in My Page, eliminating frame drops and achieving smooth 60fps scrolling.
OEM Accessibility & Usage Stats Guarding
Designed customized onboarding wizards for major OEM ROMs (Xiaomi, Huawei, OPPO) to prevent accidental permission revocation.
Local Usage Event Aggregation
Locally aggregated and compressed UsageEvents before batch transmission, substantially minimizing network bandwidth and battery draw.
Sports IoT app (Vitality Coach & BLE Sensors)
Smart fitness IoT mobile application integrating BLE fitness equipment and wearable sensors, offering live vitality coaching, resistance tuning, and workout metrics.
Key Responsibilities & Highlights
- Independently implemented the Vitality Coach UI, animations, and training routines.
- Architected and maintained local Room Database for high-frequency sensor readings and workout sessions.
- Resolved device compatibility quirks during BLE advertisement scanning across varied Android vendors.
Engineering Architecture & Technical HighlightsExpand ▾
Time-series Fitness Database Architecture
Designed Room entities for workout sessions with second-by-second telemetry records, supporting fast aggregate queries.
Custom Coach Animation Views
Built custom Views and property animators for coach rhythm indicators and power gauges, achieving solid 60fps animations.
Dispatch Taxi app (Rider Platform)
Commercial taxi dispatch passenger app evolved from v8.0 to v9.0, refactored to Kotlin with map routing, fare estimation, FCM push matching, and ad integration.
Key Responsibilities & Highlights
- Maintained version 8.0 and resolved critical production defects.
- Refactored the application from Java to Kotlin, modernizing the codebase.
- Built version 9.0 UI from scratch according to updated product designs.
- Engineered login, ride booking, push notifications, smooth vehicle tracking, ad mediation, and Crashlytics.
- Employed industry-standard toolset: Retrofit, OkHttp, RxJava, Dagger2, etc.
Engineering Architecture & Technical HighlightsExpand ▾
Full Codebase Migration to Kotlin
Spearheaded the migration of legacy Java code to Kotlin, leveraging Null Safety and extension functions to eliminate NullPointerExceptions.
MVVM Architecture with Dagger2
Introduced Dagger2 dependency injection alongside Retrofit + OkHttp + RxJava to establish clean separation of concerns.
Google Maps Polyline Decoding & Route Drawing
Integrated Google Maps API to parse route JSON, implemented Polyline decoding algorithm (overview_polyline), and accurately rendered real-time route estimates.
Crash Monitoring & Ad Monetization
Integrated Firebase Crashlytics to monitor stability while incorporating Google AdMob SDK for commercial revenue generation.
Bluetooth IoT app (Industrial Inverter Controller)
Industrial-grade BLE diagnostics and control system directly connecting to inverters, parsing Modbus protocol packets, tuning frequencies, and synchronizing with MQTT clouds.
Key Responsibilities & Highlights
- Maintained core application and implemented new features for industrial clients.
- Integrated robust BLE device discovery, connection, and characteristic notification mechanisms.
- Decoded Modbus communication protocol, translating raw binary packets into readable telemetry.
- Implemented critical control capabilities: authentication, device state reading, and dynamic frequency/voltage/temperature adjustments.
- Synchronized operational data with central MQTT telemetry servers.
- Authored automated UI test suites with Appium.
Engineering Architecture & Technical HighlightsExpand ▾
Custom Modbus Binary Parsing Engine
Built custom CRC16 check and byte parsing utilities for packet chunking across BLE MTU limits, reconstructing integer and floating-point registers.
Bidirectional MQTT Cloud Communication
Implemented MQTT with QoS 1 message delivery guarantees to feed industrial telemetry into cloud dashboards.
Automated QA with Appium
Wrote automated Appium Python regression test suites validating critical parameter limits and boundary validation rules.
Terminal Management System (POS & IoT Solution)
End-to-end POS hardware startup, multi-process AIDL IPC, Management Client, third-party SDK, ticketing transactions, and AWS Lambda remote provisioning.
Key Responsibilities & Highlights
- Comprises Management App, System SDK, Startup Splash App, AWS Lambda integration, Update Service, and Ticketing System.
- Management App with Terminal Agent: Built UI, networking, storage, and AIDL inter-process communication.
- System SDK designed for third-party developers: Provided clean API contracts and integration libraries.
- Startup Splash app: Listened for boot signals, initialized POS hardware, and performed startup authentication.
- AWS Lambda + S3: Triggered automated POS configuration commands based on cloud business rules.
- Update Service and Ticketing App: Delivered customized transaction experiences leveraging POS peripheral hardware.
Engineering Architecture & Technical HighlightsExpand ▾
AIDL Multi-Process Interface Design
Designed low-latency AIDL contracts linking the UI application with background hardware daemons for secure peripheral multiplexing.
Developer-Friendly System SDK
Abstracted complex low-level POS protocols into an intuitive Android SDK complete with JavaDoc and sample reference implementations.
AWS Lambda + S3 Event-Driven Architecture
Architected cloud event-driven workflows where operational triggers in Lambda dispatch commands down to targeted POS fleets.