Initial commit

.gitignore

@@ -0,0 +1,33 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.swiftpm/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+# Libraries should not include pubspec.lock, per https://dart.dev/guides/libraries/private-files#pubspeclock.
+/pubspec.lock
+**/doc/api/
+.dart_tool/
+.flutter-plugins-dependencies
+/build/
+/coverage/

.metadata

@@ -0,0 +1,30 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "d693b4b9dbac2acd4477aea4555ca6dcbea44ba2"
+  channel: "stable"
+
+project_type: plugin
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+    - platform: android
+      create_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+      base_revision: d693b4b9dbac2acd4477aea4555ca6dcbea44ba2
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'

CHANGELOG.md

@@ -0,0 +1,3 @@
+## 0.0.1
+
+* TODO: Describe initial release.

LICENSE

@@ -0,0 +1 @@
+TODO: Add your license here.

README.md

@@ -0,0 +1,18 @@
+# flutter_usb_serial
+
+A new Flutter plugin project.
+
+## Getting Started
+
+This project is a starting point for a Flutter
+[plug-in package](https://flutter.dev/to/develop-plugins),
+a specialized package that includes platform-specific implementation code for
+Android and/or iOS.
+
+For help getting started with Flutter development, view the
+[online documentation](https://docs.flutter.dev), which offers tutorials,
+samples, guidance on mobile development, and a full API reference.
+
+The plugin project was generated without specifying the `--platforms` flag, no platforms are currently supported.
+To add platforms, run `flutter create -t plugin --platforms <platforms> .` in this directory.
+You can also find a detailed instruction on how to add platforms in the `pubspec.yaml` at https://flutter.dev/to/pubspec-plugin-platforms.

analysis_options.yaml

@@ -0,0 +1,4 @@
+include: package:flutter_lints/flutter.yaml
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

android/.gitignore

@@ -0,0 +1,9 @@
+*.iml
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures
+.cxx

android/build.gradle

@@ -0,0 +1,51 @@
+group = "com.dalimaster.flutter_usb_serial"
+version = "1.0-SNAPSHOT"
+
+buildscript {
+    ext.kotlin_version = "2.1.0"
+    repositories {
+        google()
+        mavenCentral()
+    }
+    dependencies {
+        classpath("com.android.tools.build:gradle:8.9.1")
+        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version")
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+apply plugin: "com.android.library"
+apply plugin: "kotlin-android"
+
+android {
+    namespace = "com.dalimaster.flutter_usb_serial"
+    compileSdk = 36
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_11
+    }
+
+    sourceSets {
+        main.java.srcDirs += "src/main/kotlin"
+    }
+
+    defaultConfig {
+        minSdk = 21
+    }
+}
+
+dependencies {
+    // usb-serial-for-android as a local module included via settings.gradle
+    implementation project(':usbSerialForAndroid')
+}

android/settings.gradle

@@ -0,0 +1,7 @@
+// Include the usb-serial-for-android library as a local module.
+// The path is relative to this settings.gradle file.
+include ':usbSerialForAndroid'
+project(':usbSerialForAndroid').projectDir = new File(
+    rootProject.projectDir,
+    '../../../temp/usb-serial-for-android/usbSerialForAndroid'
+)

android/src/main/AndroidManifest.xml

@@ -0,0 +1,4 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- Required to enumerate USB devices -->
+    <uses-feature android:name="android.hardware.usb.host" android:required="false" />
+</manifest>

android/src/main/kotlin/com/dalimaster/flutter_usb_serial/FlutterUsbSerialPlugin.kt

@@ -0,0 +1,322 @@
+package com.dalimaster.flutter_usb_serial
+
+import android.app.PendingIntent
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.hardware.usb.UsbDevice
+import android.hardware.usb.UsbManager
+import android.os.Build
+import com.hoho.android.usbserial.driver.UsbSerialPort
+import com.hoho.android.usbserial.driver.UsbSerialProber
+import com.hoho.android.usbserial.util.SerialInputOutputManager
+import io.flutter.embedding.engine.plugins.FlutterPlugin
+import io.flutter.embedding.engine.plugins.activity.ActivityAware
+import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding
+import io.flutter.plugin.common.EventChannel
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import io.flutter.plugin.common.MethodChannel.MethodCallHandler
+import io.flutter.plugin.common.MethodChannel.Result
+import java.io.IOException
+
+class FlutterUsbSerialPlugin :
+    FlutterPlugin,
+    MethodCallHandler,
+    EventChannel.StreamHandler,
+    ActivityAware {
+
+    companion object {
+        private const val ACTION_USB_PERMISSION =
+            "com.dalimaster.flutter_usb_serial.USB_PERMISSION"
+        private const val METHOD_CHANNEL = "flutter_usb_serial/methods"
+        private const val EVENT_CHANNEL = "flutter_usb_serial/data"
+    }
+
+    private lateinit var methodChannel: MethodChannel
+    private lateinit var eventChannel: EventChannel
+    private lateinit var context: Context
+    private lateinit var usbManager: UsbManager
+
+    @Volatile
+    private var eventSink: EventChannel.EventSink? = null
+
+    private data class PortHandle(
+        val id: Int,
+        val port: UsbSerialPort,
+        val ioManager: SerialInputOutputManager,
+    )
+
+    private var nextPortId = 1
+    private val openPorts = mutableMapOf<Int, PortHandle>()
+    private val portsLock = Any()
+
+    private data class PendingPermission(val device: UsbDevice, val result: Result)
+
+    @Volatile
+    private var pendingPermission: PendingPermission? = null
+    private val permissionLock = Any()
+
+    private val permissionReceiver = object : BroadcastReceiver() {
+        override fun onReceive(ctx: Context?, intent: Intent?) {
+            if (intent?.action != ACTION_USB_PERMISSION) return
+            val device: UsbDevice? = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                intent.getParcelableExtra(UsbManager.EXTRA_DEVICE, UsbDevice::class.java)
+            } else {
+                @Suppress("DEPRECATION")
+                intent.getParcelableExtra(UsbManager.EXTRA_DEVICE)
+            }
+            val granted = intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)
+            var pending: PendingPermission? = null
+            synchronized(permissionLock) {
+                if (device != null && pendingPermission?.device?.deviceId == device.deviceId) {
+                    pending = pendingPermission
+                    pendingPermission = null
+                }
+            }
+            pending?.result?.success(granted)
+        }
+    }
+
+    // ── FlutterPlugin ────────────────────────────────────────────────────────
+
+    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        context = binding.applicationContext
+        usbManager = context.getSystemService(Context.USB_SERVICE) as UsbManager
+
+        methodChannel = MethodChannel(binding.binaryMessenger, METHOD_CHANNEL)
+        methodChannel.setMethodCallHandler(this)
+
+        eventChannel = EventChannel(binding.binaryMessenger, EVENT_CHANNEL)
+        eventChannel.setStreamHandler(this)
+
+        val filter = IntentFilter(ACTION_USB_PERMISSION)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            context.registerReceiver(permissionReceiver, filter, Context.RECEIVER_NOT_EXPORTED)
+        } else {
+            context.registerReceiver(permissionReceiver, filter)
+        }
+    }
+
+    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        methodChannel.setMethodCallHandler(null)
+        eventChannel.setStreamHandler(null)
+        context.unregisterReceiver(permissionReceiver)
+        closeAllPorts()
+    }
+
+    // ── ActivityAware ────────────────────────────────────────────────────────
+
+    override fun onAttachedToActivity(binding: ActivityPluginBinding) {}
+    override fun onDetachedFromActivityForConfigChanges() {}
+    override fun onReattachedToActivityForConfigChanges(binding: ActivityPluginBinding) {}
+    override fun onDetachedFromActivity() {}
+
+    // ── EventChannel.StreamHandler ───────────────────────────────────────────
+
+    override fun onListen(arguments: Any?, events: EventChannel.EventSink?) {
+        eventSink = events
+    }
+
+    override fun onCancel(arguments: Any?) {
+        eventSink = null
+    }
+
+    // ── MethodCallHandler ────────────────────────────────────────────────────
+
+    override fun onMethodCall(call: MethodCall, result: Result) {
+        when (call.method) {
+            "listDevices" -> listDevices(result)
+            "requestPermission" -> requestPermission(call, result)
+            "openPort" -> openPort(call, result)
+            "write" -> write(call, result)
+            "close" -> closePort(call, result)
+            else -> result.notImplemented()
+        }
+    }
+
+    // ── Method implementations ───────────────────────────────────────────────
+
+    private fun listDevices(result: Result) {
+        val devices = usbManager.deviceList.values.mapNotNull { device ->
+            encodeDevice(device)
+        }
+        result.success(devices)
+    }
+
+    private fun requestPermission(call: MethodCall, result: Result) {
+        val deviceId = call.argument<Int>("deviceId") ?: run {
+            result.error("INVALID_ARGUMENT", "deviceId required", null)
+            return
+        }
+        val device = usbManager.deviceList.values.firstOrNull { it.deviceId == deviceId }
+        if (device == null) {
+            result.error("DEVICE_NOT_FOUND", "USB device $deviceId not found", null)
+            return
+        }
+        if (usbManager.hasPermission(device)) {
+            result.success(true)
+            return
+        }
+        synchronized(permissionLock) {
+            pendingPermission = PendingPermission(device, result)
+        }
+        val flags = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S)
+            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE
+        else
+            PendingIntent.FLAG_UPDATE_CURRENT
+        val intent = Intent(ACTION_USB_PERMISSION).apply { setPackage(context.packageName) }
+        val pi = PendingIntent.getBroadcast(context, 0, intent, flags)
+        usbManager.requestPermission(device, pi)
+    }
+
+    private fun openPort(call: MethodCall, result: Result) {
+        val deviceId = call.argument<Int>("deviceId") ?: run {
+            result.error("INVALID_ARGUMENT", "deviceId required", null)
+            return
+        }
+        val baudRate = call.argument<Int>("baudRate") ?: 9600
+        val dataBits = call.argument<Int>("dataBits") ?: 8
+        val parity = call.argument<Int>("parity") ?: UsbSerialPort.PARITY_NONE
+        val stopBits = call.argument<Int>("stopBits") ?: UsbSerialPort.STOPBITS_1
+
+        val device = usbManager.deviceList.values.firstOrNull { it.deviceId == deviceId }
+        if (device == null) {
+            result.error("DEVICE_NOT_FOUND", "USB device $deviceId not found", null)
+            return
+        }
+        if (!usbManager.hasPermission(device)) {
+            result.error("PERMISSION_DENIED", "USB permission not granted for device $deviceId", null)
+            return
+        }
+        val driver = UsbSerialProber.getDefaultProber().probeDevice(device)
+        if (driver == null || driver.ports.isEmpty()) {
+            result.error("NO_DRIVER", "No serial driver found for device $deviceId", null)
+            return
+        }
+        val connection = usbManager.openDevice(device)
+        if (connection == null) {
+            result.error("OPEN_FAILED", "Failed to open USB connection for device $deviceId", null)
+            return
+        }
+        val port = driver.ports[0]
+        try {
+            port.open(connection)
+            port.setParameters(baudRate, dataBits, stopBits, parity)
+        } catch (e: IOException) {
+            result.error("OPEN_FAILED", "Failed to configure port: ${e.message}", null)
+            return
+        }
+
+        val portId: Int
+        synchronized(portsLock) {
+            portId = nextPortId++
+        }
+
+        val ioManager = SerialInputOutputManager(
+            port,
+            object : SerialInputOutputManager.Listener {
+                override fun onNewData(data: ByteArray) {
+                    val sink = eventSink ?: return
+                    val event = mapOf("portId" to portId, "type" to "data", "data" to data)
+                    // EventSink must be called on the main thread
+                    android.os.Handler(android.os.Looper.getMainLooper()).post {
+                        sink.success(event)
+                    }
+                }
+
+                override fun onRunError(e: Exception) {
+                    // Clean up immediately so the port is no longer usable
+                    synchronized(portsLock) { openPorts.remove(portId) }
+                    try { port.close() } catch (_: IOException) {}
+                    val sink = eventSink ?: return
+                    val event = mapOf(
+                        "portId" to portId,
+                        "type" to "error",
+                        "message" to (e.message ?: "IO error"),
+                    )
+                    android.os.Handler(android.os.Looper.getMainLooper()).post {
+                        sink.success(event)
+                    }
+                }
+            }
+        )
+        ioManager.start()
+
+        synchronized(portsLock) {
+            openPorts[portId] = PortHandle(portId, port, ioManager)
+        }
+        result.success(portId)
+    }
+
+    private fun write(call: MethodCall, result: Result) {
+        val portId = call.argument<Int>("portId") ?: run {
+            result.error("INVALID_ARGUMENT", "portId required", null)
+            return
+        }
+        val data = call.argument<ByteArray>("data") ?: run {
+            result.error("INVALID_ARGUMENT", "data required", null)
+            return
+        }
+        val handle = synchronized(portsLock) { openPorts[portId] }
+        if (handle == null) {
+            result.error("PORT_NOT_FOUND", "Port $portId is not open", null)
+            return
+        }
+        try {
+            handle.port.write(data, 2000)
+            result.success(data.size)
+        } catch (e: IOException) {
+            result.error("WRITE_FAILED", e.message, null)
+        }
+    }
+
+    private fun closePort(call: MethodCall, result: Result) {
+        val portId = call.argument<Int>("portId") ?: run {
+            result.error("INVALID_ARGUMENT", "portId required", null)
+            return
+        }
+        val handle = synchronized(portsLock) { openPorts.remove(portId) }
+        if (handle != null) {
+            handle.ioManager.stop()
+            try {
+                handle.port.close()
+            } catch (_: IOException) {}
+        }
+        result.success(null)
+    }
+
+    private fun closeAllPorts() {
+        val handles = synchronized(portsLock) {
+            val all = openPorts.values.toList()
+            openPorts.clear()
+            all
+        }
+        for (handle in handles) {
+            handle.ioManager.stop()
+            try {
+                handle.port.close()
+            } catch (_: IOException) {}
+        }
+    }
+
+    // ── Helpers ──────────────────────────────────────────────────────────────
+
+    private fun encodeDevice(device: UsbDevice): Map<String, Any?> = mapOf(
+        "deviceId" to device.deviceId,
+        "vendorId" to device.vendorId,
+        "productId" to device.productId,
+        "deviceName" to device.deviceName,
+        "manufacturerName" to (
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
+                try { device.manufacturerName ?: "" } catch (_: SecurityException) { "" }
+            else ""
+        ),
+        "serialNumber" to (
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP)
+                try { device.serialNumber ?: "" } catch (_: SecurityException) { "" }
+            else ""
+        ),
+    )
+}

android/src/test/kotlin/com/dalimaster/flutter_usb_serial/FlutterUsbSerialPluginTest.kt

@@ -0,0 +1,27 @@
+package com.dalimaster.flutter_usb_serial
+
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import org.mockito.Mockito
+import kotlin.test.Test
+
+/*
+ * This demonstrates a simple unit test of the Kotlin portion of this plugin's implementation.
+ *
+ * Once you have built the plugin's example app, you can run these tests from the command
+ * line by running `./gradlew testDebugUnitTest` in the `example/android/` directory, or
+ * you can run them directly from IDEs that support JUnit such as Android Studio.
+ */
+
+internal class FlutterUsbSerialPluginTest {
+    @Test
+    fun onMethodCall_getPlatformVersion_returnsExpectedValue() {
+        val plugin = FlutterUsbSerialPlugin()
+
+        val call = MethodCall("getPlatformVersion", null)
+        val mockResult: MethodChannel.Result = Mockito.mock(MethodChannel.Result::class.java)
+        plugin.onMethodCall(call, mockResult)
+
+        Mockito.verify(mockResult).success("Android " + android.os.Build.VERSION.RELEASE)
+    }
+}

example/.gitignore

@@ -0,0 +1,45 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.swiftpm/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins-dependencies
+.pub-cache/
+.pub/
+/build/
+/coverage/
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+/android/app/debug
+/android/app/profile
+/android/app/release

example/README.md

@@ -0,0 +1,16 @@
+# flutter_usb_serial_example
+
+Demonstrates how to use the flutter_usb_serial plugin.
+
+## Getting Started
+
+This project is a starting point for a Flutter application.
+
+A few resources to get you started if this is your first Flutter project:
+
+- [Lab: Write your first Flutter app](https://docs.flutter.dev/get-started/codelab)
+- [Cookbook: Useful Flutter samples](https://docs.flutter.dev/cookbook)
+
+For help getting started with Flutter development, view the
+[online documentation](https://docs.flutter.dev/), which offers tutorials,
+samples, guidance on mobile development, and a full API reference.

example/analysis_options.yaml

@@ -0,0 +1,28 @@
+# This file configures the analyzer, which statically analyzes Dart code to
+# check for errors, warnings, and lints.
+#
+# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
+# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
+# invoked from the command line by running `flutter analyze`.
+
+# The following line activates a set of recommended lints for Flutter apps,
+# packages, and plugins designed to encourage good coding practices.
+include: package:flutter_lints/flutter.yaml
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at https://dart.dev/lints.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
+    # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

example/android/.gitignore

@@ -0,0 +1,14 @@
+gradle-wrapper.jar
+/.gradle
+/captures/
+/gradlew
+/gradlew.bat
+/local.properties
+GeneratedPluginRegistrant.java
+.cxx/
+
+# Remember to never publicly share your keystore.
+# See https://flutter.dev/to/reference-keystore
+key.properties
+**/*.keystore
+**/*.jks

example/android/app/build.gradle.kts

@@ -0,0 +1,44 @@
+plugins {
+    id("com.android.application")
+    id("kotlin-android")
+    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
+    id("dev.flutter.flutter-gradle-plugin")
+}
+
+android {
+    namespace = "com.dalimaster.flutter_usb_serial_example"
+    compileSdk = flutter.compileSdkVersion
+    ndkVersion = flutter.ndkVersion
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_11.toString()
+    }
+
+    defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId = "com.dalimaster.flutter_usb_serial_example"
+        // You can update the following values to match your application needs.
+        // For more information, see: https://flutter.dev/to/review-gradle-config.
+        minSdk = flutter.minSdkVersion
+        targetSdk = flutter.targetSdkVersion
+        versionCode = flutter.versionCode
+        versionName = flutter.versionName
+    }
+
+    buildTypes {
+        release {
+            // TODO: Add your own signing config for the release build.
+            // Signing with the debug keys for now, so `flutter run --release` works.
+            signingConfig = signingConfigs.getByName("debug")
+        }
+    }
+}
+
+flutter {
+    source = "../.."
+}

example/android/app/src/debug/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- The INTERNET permission is required for development. Specifically,
+         the Flutter tool needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

example/android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,45 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <application
+        android:label="flutter_usb_serial_example"
+        android:name="${applicationName}"
+        android:icon="@mipmap/ic_launcher">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:launchMode="singleTop"
+            android:taskAffinity=""
+            android:theme="@style/LaunchTheme"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
+            android:windowSoftInputMode="adjustResize">
+            <!-- Specifies an Android theme to apply to this Activity as soon as
+                 the Android process has started. This theme is visible to the user
+                 while the Flutter UI initializes. After that, this theme continues
+                 to determine the Window background behind the Flutter UI. -->
+            <meta-data
+              android:name="io.flutter.embedding.android.NormalTheme"
+              android:resource="@style/NormalTheme"
+              />
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+        <!-- Don't delete the meta-data below.
+             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
+    </application>
+    <!-- Required to query activities that can process text, see:
+         https://developer.android.com/training/package-visibility and
+         https://developer.android.com/reference/android/content/Intent#ACTION_PROCESS_TEXT.
+
+         In particular, this is used by the Flutter engine in io.flutter.plugin.text.ProcessTextPlugin. -->
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.PROCESS_TEXT"/>
+            <data android:mimeType="text/plain"/>
+        </intent>
+    </queries>
+</manifest>

example/android/app/src/main/kotlin/com/dalimaster/flutter_usb_serial_example/MainActivity.kt

@@ -0,0 +1,5 @@
+package com.dalimaster.flutter_usb_serial_example
+
+import io.flutter.embedding.android.FlutterActivity
+
+class MainActivity : FlutterActivity()

example/android/app/src/main/res/drawable-v21/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="?android:colorBackground" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

example/android/app/src/main/res/drawable/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@android:color/white" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

example/android/app/src/main/res/values-night/styles.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is on -->
+    <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <!-- Show a splash screen on the activity. Automatically removed when
+             the Flutter engine draws its first frame -->
+        <item name="android:windowBackground">@drawable/launch_background</item>
+    </style>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <item name="android:windowBackground">?android:colorBackground</item>
+    </style>
+</resources>

example/android/app/src/main/res/values/styles.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is off -->
+    <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar">
+        <!-- Show a splash screen on the activity. Automatically removed when
+             the Flutter engine draws its first frame -->
+        <item name="android:windowBackground">@drawable/launch_background</item>
+    </style>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Light.NoTitleBar">
+        <item name="android:windowBackground">?android:colorBackground</item>
+    </style>
+</resources>

example/android/app/src/profile/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- The INTERNET permission is required for development. Specifically,
+         the Flutter tool needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

example/android/build.gradle.kts

@@ -0,0 +1,24 @@
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+val newBuildDir: Directory =
+    rootProject.layout.buildDirectory
+        .dir("../../build")
+        .get()
+rootProject.layout.buildDirectory.value(newBuildDir)
+
+subprojects {
+    val newSubprojectBuildDir: Directory = newBuildDir.dir(project.name)
+    project.layout.buildDirectory.value(newSubprojectBuildDir)
+}
+subprojects {
+    project.evaluationDependsOn(":app")
+}
+
+tasks.register<Delete>("clean") {
+    delete(rootProject.layout.buildDirectory)
+}

example/android/gradle.properties

@@ -0,0 +1,3 @@
+org.gradle.jvmargs=-Xmx8G -XX:MaxMetaspaceSize=4G -XX:ReservedCodeCacheSize=512m -XX:+HeapDumpOnOutOfMemoryError
+android.useAndroidX=true
+android.enableJetifier=true

example/android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-all.zip

example/android/settings.gradle.kts

@@ -0,0 +1,26 @@
+pluginManagement {
+    val flutterSdkPath =
+        run {
+            val properties = java.util.Properties()
+            file("local.properties").inputStream().use { properties.load(it) }
+            val flutterSdkPath = properties.getProperty("flutter.sdk")
+            require(flutterSdkPath != null) { "flutter.sdk not set in local.properties" }
+            flutterSdkPath
+        }
+
+    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")
+
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+plugins {
+    id("dev.flutter.flutter-plugin-loader") version "1.0.0"
+    id("com.android.application") version "8.9.1" apply false
+    id("org.jetbrains.kotlin.android") version "2.1.0" apply false
+}
+
+include(":app")

example/integration_test/plugin_integration_test.dart

@@ -0,0 +1,25 @@
+// This is a basic Flutter integration test.
+//
+// Since integration tests run in a full Flutter application, they can interact
+// with the host side of a plugin implementation, unlike Dart unit tests.
+//
+// For more information about Flutter integration tests, please see
+// https://flutter.dev/to/integration-testing
+
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:integration_test/integration_test.dart';
+
+import 'package:flutter_usb_serial/flutter_usb_serial.dart';
+
+void main() {
+  IntegrationTestWidgetsFlutterBinding.ensureInitialized();
+
+  testWidgets('getPlatformVersion test', (WidgetTester tester) async {
+    final FlutterUsbSerial plugin = FlutterUsbSerial();
+    final String? version = await plugin.getPlatformVersion();
+    // The version string depends on the host platform running the test, so
+    // just assert that some non-empty string is returned.
+    expect(version?.isNotEmpty, true);
+  });
+}

example/lib/main.dart

@@ -0,0 +1,63 @@
+import 'package:flutter/material.dart';
+import 'dart:async';
+
+import 'package:flutter/services.dart';
+import 'package:flutter_usb_serial/flutter_usb_serial.dart';
+
+void main() {
+  runApp(const MyApp());
+}
+
+class MyApp extends StatefulWidget {
+  const MyApp({super.key});
+
+  @override
+  State<MyApp> createState() => _MyAppState();
+}
+
+class _MyAppState extends State<MyApp> {
+  String _platformVersion = 'Unknown';
+  final _flutterUsbSerialPlugin = FlutterUsbSerial();
+
+  @override
+  void initState() {
+    super.initState();
+    initPlatformState();
+  }
+
+  // Platform messages are asynchronous, so we initialize in an async method.
+  Future<void> initPlatformState() async {
+    String platformVersion;
+    // Platform messages may fail, so we use a try/catch PlatformException.
+    // We also handle the message potentially returning null.
+    try {
+      platformVersion =
+          await _flutterUsbSerialPlugin.getPlatformVersion() ?? 'Unknown platform version';
+    } on PlatformException {
+      platformVersion = 'Failed to get platform version.';
+    }
+
+    // If the widget was removed from the tree while the asynchronous platform
+    // message was in flight, we want to discard the reply rather than calling
+    // setState to update our non-existent appearance.
+    if (!mounted) return;
+
+    setState(() {
+      _platformVersion = platformVersion;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text('Plugin example app'),
+        ),
+        body: Center(
+          child: Text('Running on: $_platformVersion\n'),
+        ),
+      ),
+    );
+  }
+}

example/pubspec.lock

@@ -0,0 +1,283 @@
+# Generated by pub
+# See https://dart.dev/tools/pub/glossary#lockfile
+packages:
+  async:
+    dependency: transitive
+    description:
+      name: async
+      sha256: e2eb0491ba5ddb6177742d2da23904574082139b07c1e33b8503b9f46f3e1a37
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.13.1"
+  boolean_selector:
+    dependency: transitive
+    description:
+      name: boolean_selector
+      sha256: "8aab1771e1243a5063b8b0ff68042d67334e3feab9e95b9490f9a6ebf73b42ea"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.2"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      sha256: f71061c654a3380576a52b451dd5532377954cf9dbd272a78fc8479606670803
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.0"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      sha256: fddb70d9b5277016c77a80201021d40a2247104d9f4aa7bab7157b7e3f05b84b
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.2"
+  collection:
+    dependency: transitive
+    description:
+      name: collection
+      sha256: "2f5709ae4d3d59dd8f7cd309b4e023046b57d8a6c82130785d2b0e5868084e76"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.19.1"
+  cupertino_icons:
+    dependency: "direct main"
+    description:
+      name: cupertino_icons
+      sha256: "41e005c33bd814be4d3096aff55b1908d419fde52ca656c8c47719ec745873cd"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.9"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      sha256: "5368f224a74523e8d2e7399ea1638b37aecfca824a3cc4dfdf77bf1fa905ac44"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.3"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      sha256: a3b4f84adafef897088c160faf7dfffb7696046cb13ae90b508c2cbc95d3b8d4
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.1"
+  flutter:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  flutter_driver:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  flutter_lints:
+    dependency: "direct dev"
+    description:
+      name: flutter_lints
+      sha256: "5398f14efa795ffb7a33e9b6a08798b26a180edac4ad7db3f231e40f82ce11e1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.0.0"
+  flutter_test:
+    dependency: "direct dev"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  flutter_usb_serial:
+    dependency: "direct main"
+    description:
+      path: ".."
+      relative: true
+    source: path
+    version: "0.1.0"
+  fuchsia_remote_debug_protocol:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  integration_test:
+    dependency: "direct dev"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  leak_tracker:
+    dependency: transitive
+    description:
+      name: leak_tracker
+      sha256: "33e2e26bdd85a0112ec15400c8cbffea70d0f9c3407491f672a2fad47915e2de"
+      url: "https://pub.dev"
+    source: hosted
+    version: "11.0.2"
+  leak_tracker_flutter_testing:
+    dependency: transitive
+    description:
+      name: leak_tracker_flutter_testing
+      sha256: "1dbc140bb5a23c75ea9c4811222756104fbcd1a27173f0c34ca01e16bea473c1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.10"
+  leak_tracker_testing:
+    dependency: transitive
+    description:
+      name: leak_tracker_testing
+      sha256: "8d5a2d49f4a66b49744b23b018848400d23e54caf9463f4eb20df3eb8acb2eb1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.2"
+  lints:
+    dependency: transitive
+    description:
+      name: lints
+      sha256: c35bb79562d980e9a453fc715854e1ed39e24e7d0297a880ef54e17f9874a9d7
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.1.1"
+  matcher:
+    dependency: transitive
+    description:
+      name: matcher
+      sha256: dc58c723c3c24bf8d3e2d3ad3f2f9d7bd9cf43ec6feaa64181775e60190153f2
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.12.17"
+  material_color_utilities:
+    dependency: transitive
+    description:
+      name: material_color_utilities
+      sha256: f7142bb1154231d7ea5f96bc7bde4bda2a0945d2806bb11670e30b850d56bdec
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.11.1"
+  meta:
+    dependency: transitive
+    description:
+      name: meta
+      sha256: e3641ec5d63ebf0d9b41bd43201a66e3fc79a65db5f61fc181f04cd27aab950c
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.16.0"
+  path:
+    dependency: transitive
+    description:
+      name: path
+      sha256: "75cca69d1490965be98c73ceaea117e8a04dd21217b37b292c9ddbec0d955bc5"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.9.1"
+  platform:
+    dependency: transitive
+    description:
+      name: platform
+      sha256: "5d6b1b0036a5f331ebc77c850ebc8506cbc1e9416c27e59b439f917a902a4984"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.6"
+  plugin_platform_interface:
+    dependency: transitive
+    description:
+      name: plugin_platform_interface
+      sha256: "4820fbfdb9478b1ebae27888254d445073732dae3d6ea81f0b7e06d5dedc3f02"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.8"
+  process:
+    dependency: transitive
+    description:
+      name: process
+      sha256: c6248e4526673988586e8c00bb22a49210c258dc91df5227d5da9748ecf79744
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.0.5"
+  sky_engine:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  source_span:
+    dependency: transitive
+    description:
+      name: source_span
+      sha256: "56a02f1f4cd1a2d96303c0144c93bd6d909eea6bee6bf5a0e0b685edbd4c47ab"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.10.2"
+  stack_trace:
+    dependency: transitive
+    description:
+      name: stack_trace
+      sha256: "8b27215b45d22309b5cddda1aa2b19bdfec9df0e765f2de506401c071d38d1b1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.12.1"
+  stream_channel:
+    dependency: transitive
+    description:
+      name: stream_channel
+      sha256: "969e04c80b8bcdf826f8f16579c7b14d780458bd97f56d107d3950fdbeef059d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.4"
+  string_scanner:
+    dependency: transitive
+    description:
+      name: string_scanner
+      sha256: "921cd31725b72fe181906c6a94d987c78e3b98c2e205b397ea399d4054872b43"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.1"
+  sync_http:
+    dependency: transitive
+    description:
+      name: sync_http
+      sha256: "7f0cd72eca000d2e026bcd6f990b81d0ca06022ef4e32fb257b30d3d1014a961"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.3.1"
+  term_glyph:
+    dependency: transitive
+    description:
+      name: term_glyph
+      sha256: "7f554798625ea768a7518313e58f83891c7f5024f88e46e7182a4558850a4b8e"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.2.2"
+  test_api:
+    dependency: transitive
+    description:
+      name: test_api
+      sha256: "522f00f556e73044315fa4585ec3270f1808a4b186c936e612cab0b565ff1e00"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.7.6"
+  vector_math:
+    dependency: transitive
+    description:
+      name: vector_math
+      sha256: d530bd74fea330e6e364cda7a85019c434070188383e1cd8d9777ee586914c5b
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.0"
+  vm_service:
+    dependency: transitive
+    description:
+      name: vm_service
+      sha256: "046d3928e16fa4dc46e8350415661755ab759d9fc97fc21b5ab295f71e4f0499"
+      url: "https://pub.dev"
+    source: hosted
+    version: "15.1.0"
+  webdriver:
+    dependency: transitive
+    description:
+      name: webdriver
+      sha256: "2f3a14ca026957870cfd9c635b83507e0e51d8091568e90129fbf805aba7cade"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.0"
+sdks:
+  dart: ">=3.9.2 <4.0.0"
+  flutter: ">=3.18.0-18.0.pre.54"

example/pubspec.yaml

@@ -0,0 +1,85 @@
+name: flutter_usb_serial_example
+description: "Demonstrates how to use the flutter_usb_serial plugin."
+# The following line prevents the package from being accidentally published to
+# pub.dev using `flutter pub publish`. This is preferred for private packages.
+publish_to: 'none' # Remove this line if you wish to publish to pub.dev
+
+environment:
+  sdk: ^3.9.2
+
+# Dependencies specify other packages that your package needs in order to work.
+# To automatically upgrade your package dependencies to the latest versions
+# consider running `flutter pub upgrade --major-versions`. Alternatively,
+# dependencies can be manually updated by changing the version numbers below to
+# the latest version available on pub.dev. To see which dependencies have newer
+# versions available, run `flutter pub outdated`.
+dependencies:
+  flutter:
+    sdk: flutter
+
+  flutter_usb_serial:
+    # When depending on this package from a real application you should use:
+    #   flutter_usb_serial: ^x.y.z
+    # See https://dart.dev/tools/pub/dependencies#version-constraints
+    # The example app is bundled with the plugin so we use a path dependency on
+    # the parent directory to use the current plugin's version.
+    path: ../
+
+  # The following adds the Cupertino Icons font to your application.
+  # Use with the CupertinoIcons class for iOS style icons.
+  cupertino_icons: ^1.0.8
+
+dev_dependencies:
+  integration_test:
+    sdk: flutter
+  flutter_test:
+    sdk: flutter
+
+  # The "flutter_lints" package below contains a set of recommended lints to
+  # encourage good coding practices. The lint set provided by the package is
+  # activated in the `analysis_options.yaml` file located at the root of your
+  # package. See that file for information about deactivating specific lint
+  # rules and activating additional ones.
+  flutter_lints: ^5.0.0
+
+# For information on the generic Dart part of this file, see the
+# following page: https://dart.dev/tools/pub/pubspec
+
+# The following section is specific to Flutter packages.
+flutter:
+
+  # The following line ensures that the Material Icons font is
+  # included with your application, so that you can use the icons in
+  # the material Icons class.
+  uses-material-design: true
+
+  # To add assets to your application, add an assets section, like this:
+  # assets:
+  #   - images/a_dot_burr.jpeg
+  #   - images/a_dot_ham.jpeg
+
+  # An image asset can refer to one or more resolution-specific "variants", see
+  # https://flutter.dev/to/resolution-aware-images
+
+  # For details regarding adding assets from package dependencies, see
+  # https://flutter.dev/to/asset-from-package
+
+  # To add custom fonts to your application, add a fonts section here,
+  # in this "flutter" section. Each entry in this list should have a
+  # "family" key with the font family name, and a "fonts" key with a
+  # list giving the asset and other descriptors for the font. For
+  # example:
+  # fonts:
+  #   - family: Schyler
+  #     fonts:
+  #       - asset: fonts/Schyler-Regular.ttf
+  #       - asset: fonts/Schyler-Italic.ttf
+  #         style: italic
+  #   - family: Trajan Pro
+  #     fonts:
+  #       - asset: fonts/TrajanPro.ttf
+  #       - asset: fonts/TrajanPro_Bold.ttf
+  #         weight: 700
+  #
+  # For details regarding fonts from package dependencies,
+  # see https://flutter.dev/to/font-from-package

example/test/widget_test.dart

@@ -0,0 +1,27 @@
+// This is a basic Flutter widget test.
+//
+// To perform an interaction with a widget in your test, use the WidgetTester
+// utility in the flutter_test package. For example, you can send tap and scroll
+// gestures. You can also use WidgetTester to find child widgets in the widget
+// tree, read text, and verify that the values of widget properties are correct.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:flutter_usb_serial_example/main.dart';
+
+void main() {
+  testWidgets('Verify Platform version', (WidgetTester tester) async {
+    // Build our app and trigger a frame.
+    await tester.pumpWidget(const MyApp());
+
+    // Verify that platform version is retrieved.
+    expect(
+      find.byWidgetPredicate(
+        (Widget widget) => widget is Text &&
+                           widget.data!.startsWith('Running on:'),
+      ),
+      findsOneWidget,
+    );
+  });
+}

lib/flutter_usb_serial.dart

@@ -0,0 +1,13 @@
+/// Flutter plugin for USB serial communication on Android.
+///
+/// Uses `usb-serial-for-android` (https://github.com/mik3y/usb-serial-for-android)
+/// as the underlying Android library.
+library;
+
+import 'dart:async';
+
+import 'package:flutter/services.dart';
+
+part 'src/usb_serial_device.dart';
+part 'src/usb_serial_port.dart';
+part 'src/flutter_usb_serial.dart';

lib/flutter_usb_serial_method_channel.dart

@@ -0,0 +1,17 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
+
+import 'flutter_usb_serial_platform_interface.dart';
+
+/// An implementation of [FlutterUsbSerialPlatform] that uses method channels.
+class MethodChannelFlutterUsbSerial extends FlutterUsbSerialPlatform {
+  /// The method channel used to interact with the native platform.
+  @visibleForTesting
+  final methodChannel = const MethodChannel('flutter_usb_serial');
+
+  @override
+  Future<String?> getPlatformVersion() async {
+    final version = await methodChannel.invokeMethod<String>('getPlatformVersion');
+    return version;
+  }
+}

lib/flutter_usb_serial_platform_interface.dart

@@ -0,0 +1,29 @@
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+
+import 'flutter_usb_serial_method_channel.dart';
+
+abstract class FlutterUsbSerialPlatform extends PlatformInterface {
+  /// Constructs a FlutterUsbSerialPlatform.
+  FlutterUsbSerialPlatform() : super(token: _token);
+
+  static final Object _token = Object();
+
+  static FlutterUsbSerialPlatform _instance = MethodChannelFlutterUsbSerial();
+
+  /// The default instance of [FlutterUsbSerialPlatform] to use.
+  ///
+  /// Defaults to [MethodChannelFlutterUsbSerial].
+  static FlutterUsbSerialPlatform get instance => _instance;
+
+  /// Platform-specific implementations should set this with their own
+  /// platform-specific class that extends [FlutterUsbSerialPlatform] when
+  /// they register themselves.
+  static set instance(FlutterUsbSerialPlatform instance) {
+    PlatformInterface.verifyToken(instance, _token);
+    _instance = instance;
+  }
+
+  Future<String?> getPlatformVersion() {
+    throw UnimplementedError('platformVersion() has not been implemented.');
+  }
+}

lib/src/flutter_usb_serial.dart

@@ -0,0 +1,102 @@
+part of '../flutter_usb_serial.dart';
+
+/// Main entry point for the flutter_usb_serial plugin.
+///
+/// Only supported on Android.
+class FlutterUsbSerial {
+  FlutterUsbSerial._();
+
+  static const _methods = MethodChannel('flutter_usb_serial/methods');
+  static const _events = EventChannel('flutter_usb_serial/data');
+
+  static Stream<Map<Object?, Object?>>? _rawEventStream;
+
+  static Stream<Map<Object?, Object?>> get _eventStream {
+    _rawEventStream ??= _events
+        .receiveBroadcastStream()
+        .cast<Map<Object?, Object?>>();
+    return _rawEventStream!;
+  }
+
+  /// Returns the list of currently attached USB serial devices.
+  static Future<List<UsbSerialDevice>> listDevices() async {
+    final result = await _methods.invokeMethod<List<Object?>>('listDevices');
+    if (result == null) return [];
+    return result
+        .whereType<Map<Object?, Object?>>()
+        .map(UsbSerialDevice.fromMap)
+        .toList();
+  }
+
+  /// Requests Android USB permission for [device] if not already granted.
+  ///
+  /// Returns `true` if permission was granted (or was already held).
+  static Future<bool> requestPermission(UsbSerialDevice device) async {
+    final granted = await _methods.invokeMethod<bool>('requestPermission', {
+      'deviceId': device.deviceId,
+    });
+    return granted ?? false;
+  }
+
+  /// Opens the first port of [device] with the given serial parameters.
+  ///
+  /// [baudRate] defaults to 9600.
+  /// [dataBits] must be 5, 6, 7, or 8. Defaults to 8.
+  /// [parity] defaults to [UsbSerialParity.none].
+  /// [stopBits] defaults to [UsbSerialStopBits.one].
+  ///
+  /// The returned [UsbSerialPort] streams incoming data via [UsbSerialPort.inputStream].
+  /// Call [UsbSerialPort.close] when done.
+  static Future<UsbSerialPort> openPort(
+    UsbSerialDevice device, {
+    int baudRate = 9600,
+    int dataBits = 8,
+    UsbSerialParity parity = UsbSerialParity.none,
+    UsbSerialStopBits stopBits = UsbSerialStopBits.one,
+  }) async {
+    final portId = await _methods.invokeMethod<int>('openPort', {
+      'deviceId': device.deviceId,
+      'baudRate': baudRate,
+      'dataBits': dataBits,
+      'parity': parity.index,
+      'stopBits': _stopBitsIndex(stopBits),
+    });
+    if (portId == null) {
+      throw PlatformException(
+        code: 'OPEN_FAILED',
+        message: 'Failed to open USB serial port for device ${device.deviceId}',
+      );
+    }
+
+    final dataStream = _eventStream
+        .where((e) => e['portId'] == portId)
+        .transform(StreamTransformer<Map<Object?, Object?>, Uint8List>.fromHandlers(
+          handleData: (e, sink) {
+            if (e['type'] == 'data') {
+              final raw = e['data'];
+              if (raw is Uint8List) {
+                sink.add(raw);
+              } else if (raw is List) {
+                sink.add(Uint8List.fromList(raw.cast<int>()));
+              }
+            } else if (e['type'] == 'error') {
+              sink.addError(Exception(
+                  e['message'] as String? ?? 'USB IO error'));
+            }
+          },
+        ));
+
+    return UsbSerialPort._(portId, dataStream);
+  }
+
+  static int _stopBitsIndex(UsbSerialStopBits sb) {
+    switch (sb) {
+      case UsbSerialStopBits.one:
+        return 1;
+      case UsbSerialStopBits.onePointFive:
+        return 3; // UsbSerialPort.STOPBITS_1_5
+      case UsbSerialStopBits.two:
+        return 2;
+    }
+  }
+}

lib/src/usb_serial_device.dart

@@ -0,0 +1,56 @@
+part of '../flutter_usb_serial.dart';
+
+/// Represents a USB serial device found during enumeration.
+class UsbSerialDevice {
+  /// Unique device ID (Android USB device ID).
+  final int deviceId;
+
+  /// Vendor ID (VID).
+  final int vendorId;
+
+  /// Product ID (PID).
+  final int productId;
+
+  /// Human-readable device name (product string from descriptor, may be empty).
+  final String deviceName;
+
+  /// Manufacturer string (may be empty).
+  final String manufacturerName;
+
+  /// Serial number string (may be empty).
+  final String serialNumber;
+
+  const UsbSerialDevice({
+    required this.deviceId,
+    required this.vendorId,
+    required this.productId,
+    required this.deviceName,
+    required this.manufacturerName,
+    required this.serialNumber,
+  });
+
+  factory UsbSerialDevice.fromMap(Map<Object?, Object?> map) {
+    return UsbSerialDevice(
+      deviceId: (map['deviceId'] as int?) ?? 0,
+      vendorId: (map['vendorId'] as int?) ?? 0,
+      productId: (map['productId'] as int?) ?? 0,
+      deviceName: (map['deviceName'] as String?) ?? '',
+      manufacturerName: (map['manufacturerName'] as String?) ?? '',
+      serialNumber: (map['serialNumber'] as String?) ?? '',
+    );
+  }
+
+  Map<String, dynamic> toMap() => {
+    'deviceId': deviceId,
+    'vendorId': vendorId,
+    'productId': productId,
+    'deviceName': deviceName,
+    'manufacturerName': manufacturerName,
+    'serialNumber': serialNumber,
+  };
+
+  @override
+  String toString() =>
+      'UsbSerialDevice(id=$deviceId, vid=0x${vendorId.toRadixString(16).padLeft(4, '0')}, '
+      'pid=0x${productId.toRadixString(16).padLeft(4, '0')}, name="$deviceName")';
+}

lib/src/usb_serial_port.dart

@@ -0,0 +1,41 @@
+part of '../flutter_usb_serial.dart';
+
+/// Parity modes for serial communication.
+enum UsbSerialParity { none, odd, even, mark, space }
+
+/// Stop bits for serial communication.
+enum UsbSerialStopBits { one, onePointFive, two }
+
+/// An open serial port handle returned by [FlutterUsbSerial.openPort].
+///
+/// Call [close] when done to release native resources.
+class UsbSerialPort {
+  final int _portId;
+
+  UsbSerialPort._(this._portId, this._dataStream);
+
+  final Stream<Uint8List> _dataStream;
+
+  /// Stream of raw bytes received on this port.
+  Stream<Uint8List> get inputStream => _dataStream;
+
+  static const _methods = MethodChannel('flutter_usb_serial/methods');
+
+  /// Write [data] to the port.
+  ///
+  /// Returns the number of bytes actually written, or throws on error.
+  Future<int> write(Uint8List data) async {
+    final written = await _methods.invokeMethod<int>('write', {
+      'portId': _portId,
+      'data': data,
+    });
+    return written ?? 0;
+  }
+
+  /// Close the port and release native resources.
+  Future<void> close() async {
+    await _methods.invokeMethod<void>('close', {'portId': _portId});
+  }
+
+  int get portId => _portId;
+}

pubspec.yaml

@@ -0,0 +1,24 @@
+name: flutter_usb_serial
+description: "Flutter plugin for USB serial communication on Android using usb-serial-for-android."
+version: 0.1.0
+
+environment:
+  sdk: ^3.9.2
+  flutter: '>=3.3.0'
+
+dependencies:
+  flutter:
+    sdk: flutter
+  plugin_platform_interface: ^2.0.2
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  flutter_lints: ^5.0.0
+
+flutter:
+  plugin:
+    platforms:
+      android:
+        package: com.dalimaster.flutter_usb_serial
+        pluginClass: FlutterUsbSerialPlugin

test/flutter_usb_serial_method_channel_test.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_usb_serial/flutter_usb_serial_method_channel.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  MethodChannelFlutterUsbSerial platform = MethodChannelFlutterUsbSerial();
+  const MethodChannel channel = MethodChannel('flutter_usb_serial');
+
+  setUp(() {
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockMethodCallHandler(
+      channel,
+      (MethodCall methodCall) async {
+        return '42';
+      },
+    );
+  });
+
+  tearDown(() {
+    TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockMethodCallHandler(channel, null);
+  });
+
+  test('getPlatformVersion', () async {
+    expect(await platform.getPlatformVersion(), '42');
+  });
+}

test/flutter_usb_serial_test.dart

@@ -0,0 +1,29 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_usb_serial/flutter_usb_serial.dart';
+import 'package:flutter_usb_serial/flutter_usb_serial_platform_interface.dart';
+import 'package:flutter_usb_serial/flutter_usb_serial_method_channel.dart';
+import 'package:plugin_platform_interface/plugin_platform_interface.dart';
+
+class MockFlutterUsbSerialPlatform
+    with MockPlatformInterfaceMixin
+    implements FlutterUsbSerialPlatform {
+
+  @override
+  Future<String?> getPlatformVersion() => Future.value('42');
+}
+
+void main() {
+  final FlutterUsbSerialPlatform initialPlatform = FlutterUsbSerialPlatform.instance;
+
+  test('$MethodChannelFlutterUsbSerial is the default instance', () {
+    expect(initialPlatform, isInstanceOf<MethodChannelFlutterUsbSerial>());
+  });
+
+  test('getPlatformVersion', () async {
+    FlutterUsbSerial flutterUsbSerialPlugin = FlutterUsbSerial();
+    MockFlutterUsbSerialPlatform fakePlatform = MockFlutterUsbSerialPlatform();
+    FlutterUsbSerialPlatform.instance = fakePlatform;
+
+    expect(await flutterUsbSerialPlugin.getPlatformVersion(), '42');
+  });
+}