feat: add Android USB serial port support via USB Host API

- Add USB Host permissions and device filter to AndroidManifest.xml - Create UsbSerialPlugin Kotlin plugin for USB Host API (enumerate, permission, open devices) - Add serial_connect_fd command for Android to accept USB file descriptors - Create RawFdStream wrapper for async I/O on raw file descriptors - Make run_serial_with_poll generic over AsyncRead+AsyncWrite - Register UsbSerialPlugin in MainActivity
2026-05-11 20:31:46 +08:00
parent 7323021aec
commit 551022215c
13 changed files with 535 additions and 16 deletions
--- a/src-tauri/gen/android/app/src/main/AndroidManifest.xml
+++ b/src-tauri/gen/android/app/src/main/AndroidManifest.xml
@@ -2,6 +2,9 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-permission android:name="android.permission.INTERNET" />

+    <!-- USB Host support for serial devices -->
+    <uses-feature android:name="android.hardware.usb.host" android:required="true" />
+
    <!-- AndroidTV support -->
    <uses-feature android:name="android.software.leanback" android:required="false" />

@@ -22,6 +25,13 @@
                <!-- AndroidTV support -->
                <category android:name="android.intent.category.LEANBACK_LAUNCHER" />
            </intent-filter>
+            <!-- Auto-launch when USB device is attached -->
+            <intent-filter>
+                <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
+            </intent-filter>
+            <meta-data
+                android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
+                android:resource="@xml/usb_device_filter" />
        </activity>

        <provider
--- a/src-tauri/gen/android/app/src/main/java/com/lenn/tauri_serial/MainActivity.kt
+++ b/src-tauri/gen/android/app/src/main/java/com/lenn/tauri_serial/MainActivity.kt
@@ -7,5 +7,7 @@ class MainActivity : TauriActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    enableEdgeToEdge()
    super.onCreate(savedInstanceState)
+    val plugin = UsbSerialPlugin(this)
+    pluginManager.load(null, "usb-serial", plugin, "")
  }
-}
+}
--- a/src-tauri/gen/android/app/src/main/java/com/lenn/tauri_serial/UsbSerialPlugin.kt
+++ b/src-tauri/gen/android/app/src/main/java/com/lenn/tauri_serial/UsbSerialPlugin.kt
@@ -0,0 +1,217 @@
+package com.lenn.tauri_serial
+
+import android.app.Activity
+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.UsbDeviceConnection
+import android.hardware.usb.UsbManager
+import android.os.Build
+import app.tauri.annotation.Command
+import app.tauri.annotation.TauriPlugin
+import app.tauri.plugin.JSObject
+import app.tauri.plugin.Plugin
+import app.tauri.plugin.Invoke
+
+@TauriPlugin
+class UsbSerialPlugin(private val activity: Activity) : Plugin(activity) {
+    companion object {
+        private const val ACTION_USB_PERMISSION = "com.lenn.tauri_serial.USB_PERMISSION"
+    }
+
+    private var pendingConnectInvoke: Invoke? = null
+    private var pendingConnectDevice: UsbDevice? = null
+
+    private val usbPermissionReceiver = object : BroadcastReceiver() {
+        override fun onReceive(context: Context, intent: Intent) {
+            if (ACTION_USB_PERMISSION != intent.action) return
+
+            synchronized(this@UsbSerialPlugin) {
+                val device = 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)
+                val invoke = pendingConnectInvoke
+                val targetDevice = pendingConnectDevice
+
+                pendingConnectInvoke = null
+                pendingConnectDevice = null
+
+                if (invoke == null || device == null) return
+
+                if (!granted) {
+                    invoke.reject("USB permission denied")
+                    return
+                }
+
+                if (targetDevice != null && device.deviceName == targetDevice.deviceName) {
+                    openAndReturn(invoke, device)
+                } else {
+                    invoke.reject("USB device mismatch")
+                }
+            }
+        }
+    }
+
+    override fun load(webView: android.webkit.WebView) {
+        super.load(webView)
+        val filter = IntentFilter(ACTION_USB_PERMISSION)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            activity.applicationContext.registerReceiver(
+                usbPermissionReceiver, filter, Context.RECEIVER_NOT_EXPORTED
+            )
+        } else {
+            activity.applicationContext.registerReceiver(usbPermissionReceiver, filter)
+        }
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        try {
+            activity.applicationContext.unregisterReceiver(usbPermissionReceiver)
+        } catch (_: Exception) {}
+    }
+
+    @Command
+    fun usb_serial_list(invoke: Invoke) {
+        val usbManager = activity.getSystemService(Context.USB_SERVICE) as? UsbManager
+        if (usbManager == null) {
+            invoke.reject("USB service not available")
+            return
+        }
+
+        val devices = usbManager.deviceList
+        val result = JSObject()
+
+        val serialDevices = mutableListOf<JSObject>()
+        for ((_, device) in devices) {
+            if (isUsbSerialDevice(device)) {
+                val obj = JSObject()
+                obj.put("name", device.deviceName)
+                obj.put("vendorId", device.vendorId)
+                obj.put("productId", device.productId)
+                obj.put("manufacturer", device.manufacturerName ?: "")
+                obj.put("product", device.productName ?: "")
+                obj.put("serial", device.serialNumber ?: "")
+                obj.put("hasPermission", usbManager.hasPermission(device))
+                serialDevices.add(obj)
+            }
+        }
+
+        result.put("devices", serialDevices.toTypedArray())
+        invoke.resolve(result)
+    }
+
+    @Command
+    fun usb_serial_open(invoke: Invoke) {
+        val args = invoke.parseArgs(JSObject::class.java)
+        val deviceName = args.optString("name", "")
+
+        val usbManager = activity.getSystemService(Context.USB_SERVICE) as? UsbManager
+        if (usbManager == null) {
+            invoke.reject("USB service not available")
+            return
+        }
+
+        val device = usbManager.deviceList[deviceName]
+        if (device == null) {
+            invoke.reject("USB device not found: $deviceName")
+            return
+        }
+
+        if (!usbManager.hasPermission(device)) {
+            synchronized(this) {
+                pendingConnectInvoke = invoke
+                pendingConnectDevice = device
+            }
+
+            val flags = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+                PendingIntent.FLAG_MUTABLE
+            } else {
+                0
+            }
+            val permissionIntent = PendingIntent.getBroadcast(
+                activity, 0, Intent(ACTION_USB_PERMISSION), flags
+            )
+            usbManager.requestPermission(device, permissionIntent)
+            return
+        }
+
+        openAndReturn(invoke, device)
+    }
+
+    @Command
+    fun usb_serial_close(invoke: Invoke) {
+        invoke.resolve(JSObject())
+    }
+
+    private fun openAndReturn(invoke: Invoke, device: UsbDevice) {
+        val usbManager = activity.getSystemService(Context.USB_SERVICE) as? UsbManager
+        if (usbManager == null) {
+            invoke.reject("USB service not available")
+            return
+        }
+
+        val connection: UsbDeviceConnection = usbManager.openDevice(device)
+            ?: run {
+                invoke.reject("Failed to open USB device")
+                return
+            }
+
+        var claimedInterface = false
+        for (i in 0 until device.interfaceCount) {
+            val iface = device.getInterface(i)
+            if (iface.endpointCount >= 2) {
+                connection.claimInterface(iface, true)
+                claimedInterface = true
+                break
+            }
+        }
+
+        if (!claimedInterface) {
+            invoke.reject("No usable USB interface found")
+            return
+        }
+
+        val fd = connection.fileDescriptor
+        val result = JSObject()
+        result.put("fd", fd)
+        result.put("name", device.deviceName)
+        result.put("vendorId", device.vendorId)
+        result.put("productId", device.productId)
+        invoke.resolve(result)
+    }
+
+    private fun isUsbSerialDevice(device: UsbDevice): Boolean {
+        for (i in 0 until device.interfaceCount) {
+            val iface = device.getInterface(i)
+            val classId = iface.interfaceClass
+            if (classId == 0x02 || classId == 0xFF) {
+                if (iface.endpointCount >= 2) {
+                    return true
+                }
+            }
+        }
+
+        val knownVendors = setOf(
+            0x1A86, // CH340/CH341
+            0x10C4, // CP210x
+            0x0403, // FTDI
+            0x067B, // PL2303
+            0x2341, // Arduino
+            0x239A, // Adafruit
+        )
+        if (device.vendorId in knownVendors) {
+            return true
+        }
+
+        return false
+    }
+}
--- a/src-tauri/gen/android/app/src/main/res/xml/usb_device_filter.xml
+++ b/src-tauri/gen/android/app/src/main/res/xml/usb_device_filter.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <!-- CH340 / CH341 USB-Serial -->
+    <usb-device vendor-id="1a86" product-id="7523" />
+    <!-- CP2102 / CP2104 -->
+    <usb-device vendor-id="10c4" product-id="ea60" />
+    <usb-device vendor-id="10c4" product-id="ea70" />
+    <!-- FTDI FT232R / FT232H -->
+    <usb-device vendor-id="0403" product-id="6001" />
+    <usb-device vendor-id="0403" product-id="6014" />
+    <!-- PL2303 -->
+    <usb-device vendor-id="067b" product-id="2303" />
+    <usb-device vendor-id="067b" product-id="23a3" />
+    <!-- CDC ACM (generic USB serial) -->
+    <usb-device vendor-id="2341" product-id="0001" />
+    <usb-device vendor-id="2341" product-id="0043" />
+    <usb-device vendor-id="2341" product-id="0042" />
+    <!-- Allow any USB device (catch-all) -->
+    <usb-device />
+</resources>