ch34/.planning/codebase/STACK.md

Technology Stack

Analysis Date: 2026-04-16

Languages

Primary:

• Dart >=3.4.3 - Flutter plugin Dart-side code (lib/, test/)
• Java 8 - Android native plugin implementation (android/src/main/java/)

Secondary:

• Kotlin 1.7.10 - Declared in example app Gradle plugins (example/android/settings.gradle) but not actively used in plugin code

Runtime

Environment:

• Flutter >=3.3.0
• Android SDK - compileSdk 34, minSdk 21

Package Manager:

• pub (Dart) - Lockfile: pubspec.lock present
• Gradle 7.3.0 - Android build system

Frameworks

Core:

• Flutter >=3.3.0 - Cross-platform plugin framework
• Flutter Plugin API - FlutterPlugin, MethodCallHandler, MethodChannel, EventChannel

Testing:

• flutter_test (Flutter SDK) - Unit testing framework
• JUnit 4.13.2 - Android native unit testing
• Mockito 5.0.0 - Java mocking for Android tests
• integration_test (Flutter SDK) - Integration testing

Build/Dev:

• flutter_lints ^3.0.0 - Lint rules
• Gradle 7.3.0 - Android build automation

Key Dependencies

Critical:

• plugin_platform_interface ^2.0.2 - Federated plugin platform interface pattern (Ch34Platform extends PlatformInterface)
• CH34XUARTDriver (local JAR, 140KB) - WCH official UART library, located at android/libs/CH34XUARTDriver.jar. Provides WCHUARTManager, ChipType2, IDataCallback, IModemStatus, GPIO_Status etc.

Infrastructure:

• cupertino_icons ^1.0.6 - Example app only, Material/Cupertino icon support

Android Native Dependencies (WCH SDK):

• cn.wch.uartlib.WCHUARTManager - Core manager singleton
• cn.wch.uartlib.chipImpl.type.ChipType2 - Chip type identification
• cn.wch.uartlib.callback.IDataCallback - Serial data callback interface
• cn.wch.uartlib.callback.IModemStatus - Modem status callback interface
• cn.wch.uartlib.callback.IUsbStateChange - USB state change callback
• cn.wch.uartlib.exception.* - Exception classes (ChipException, NoPermissionException, UartLibException)

Configuration

Environment:

• analysis_options.yaml - Includes package:flutter_lints/flutter.yaml
• No .env or environment variable configuration required
• Secrets stored in example local.properties (flutter.sdk path)

Build:

• pubspec.yaml - Main plugin manifest, package: ch34, version 1.0.0
• pubspec.lock - Dependency lockfile
• android/build.gradle - Android library build config (namespace: com.example.ch34)
• android/settings.gradle - Project name: ch34
• example/android/build.gradle - Example app root build
• example/android/app/build.gradle - Example app module (namespace: com.example.ch34_example)
• example/android/settings.gradle - Gradle plugins including dev.flutter.flutter-plugin-loader

Platform Requirements

Development:

• Flutter SDK >=3.3.0
• Dart SDK >=3.4.3
• Android SDK compileSdk 34
• Java 8+ (sourceCompatibility/targetCompatibility = JavaVersion.VERSION_1_8)

Production:

• Android device with USB Host support (android.hardware.usb.host feature declared in android/src/main/AndroidManifest.xml)
• Android minSdk 21 (Android 5.0 Lollipop)
• Physical CH34X series USB-to-serial hardware connected via USB OTG

Supported Chip Models

CH340, CH341, CH342, CH343, CH344, CH347, CH9101, CH9102, CH9103, CH9104, CH9143

Build System

Flutter Plugin: Standard Flutter plugin structure with Android platform implementation.

Communication Pattern:

• MethodChannel('ch34') - 33 method calls for device control
• EventChannel('ch34/data') - Serial data streaming
• EventChannel('ch34/modem') - Modem status streaming
• EventChannel('ch34/usb_state') - USB plug/unplug events

Architecture Pattern: Federated plugin with platform interface (Ch34Platform), method channel implementation (MethodChannelCh34), and manager facade (Ch34Manager).

---

Stack analysis: 2026-04-16