feat(ch934x_serial): 添加多端口并发轮询流功能

- 新增多端口并发轮询流 portDataStream 方法，支持每周期轮询 8 个端口
- 修改 read 方法增加 serialPortIndex 参数，支持指定端口读取数据
- 更新 Android 原生实现，支持通过 serialPortIndex 参数指定读取端口
- 移除 IDataCallback 注册逻辑，改用轮询方式拉取数据避免缓冲区冲突
- 添加主线程切换机制，确保异常推送在主线程执行
- 更新 pubspec.yaml 添加 ch934x_serial 本地插件依赖
- 更新项目路线图，标记 Phase 42 完成，进度更新至 50%

android/src/main/java/com/xiarui/ch934x_serial/Ch934xSerialPlugin.java

@@ -10,6 +10,8 @@ import android.content.IntentFilter;
 import android.hardware.usb.UsbDevice;
 import android.hardware.usb.UsbManager;
 import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -22,7 +24,6 @@ import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 
 import cn.wch.ch934xlib.CH934XManager;
-import cn.wch.ch934xlib.callback.IDataCallback;
 import cn.wch.ch934xlib.callback.IModemStatus;
 import cn.wch.ch934xlib.callback.IUsbStateChange;
 import cn.wch.ch934xlib.chip.ChipType;
@@ -74,9 +75,6 @@ public class Ch934xSerialPlugin implements FlutterPlugin, MethodCallHandler, Act
     /** 当前会话选中的串口索引(对应文档 5.1.1 中的 serialPortIndex)。 */
     private int activeSerialNumber = -1;
 
-    /** 当前会话是否已注册了 IDataCallback,用于避免重复注册。 */
-    private boolean dataCallbackRegistered = false;
-
     /** 当前会话是否已注册了 IModemStatus,用于避免重复注册。 */
     private boolean modemCallbackRegistered = false;
 
@@ -153,7 +151,6 @@ public class Ch934xSerialPlugin implements FlutterPlugin, MethodCallHandler, Act
         }
         activeDevice = null;
         activeSerialNumber = -1;
-        dataCallbackRegistered = false;
         modemCallbackRegistered = false;
         exceptionCallbackEnabled = false;
     }
@@ -371,7 +368,9 @@ public class Ch934xSerialPlugin implements FlutterPlugin, MethodCallHandler, Act
         }
         activeDevice = device;
         activeSerialNumber = serialPortIndex;
-        ensureDataCallback();
+        // 注意：不注册 IDataCallback — SDK 在有回调注册时会通过回调
+        // 投递数据并释放内部缓冲区，导致 readData() 返回空。
+        // 通过 dataStream 轮询 readData() 拉取数据。
         ensureModemCallback();
         return true;
     }
@@ -486,7 +485,6 @@ public class Ch934xSerialPlugin implements FlutterPlugin, MethodCallHandler, Act
         }
         activeDevice = null;
         activeSerialNumber = -1;
-        dataCallbackRegistered = false;
         modemCallbackRegistered = false;
         modemStatusCache = 0;
         return true;
@@ -519,10 +517,13 @@ public class Ch934xSerialPlugin implements FlutterPlugin, MethodCallHandler, Act
         if (length == null || length <= 0) {
             return new byte[0];
         }
+        // 可选参数：指定读哪个端口的缓冲区。不传则读 activeSerialNumber（向后兼容）
+        Integer portIndex = call.argument("serialPortIndex");
+        int idx = (portIndex != null) ? portIndex : activeSerialNumber;
         try {
             // SDK 返回内部缓冲的所有数据,与文档 read 语义一致。
             byte[] data = CH934XManager.getInstance()
-                    .readData(activeDevice, activeSerialNumber);
+                    .readData(activeDevice, idx);
             if (data == null || data.length == 0) {
                 return new byte[0];
             }
@@ -682,25 +683,6 @@ public class Ch934xSerialPlugin implements FlutterPlugin, MethodCallHandler, Act
         return ports;
     }
 
-    /** 注册 IDataCallback 推送数据上抛(可选,目前仅用作 SDK 内部缓冲预热)。 */
-    private void ensureDataCallback() {
-        if (dataCallbackRegistered || activeDevice == null) {
-            return;
-        }
-        try {
-            CH934XManager.getInstance().registerDataCallback(activeDevice,
-                    new IDataCallback() {
-                        @Override
-                        public void onData(int serialNumber, byte[] buffer, int length) {
-                            // 数据通过 readData 拉取即可,这里留空。
-                        }
-                    });
-            dataCallbackRegistered = true;
-        } catch (Throwable t) {
-            // 注册失败不影响主流程,readData 仍可工作。
-        }
-    }
-
     private void ensureModemCallback() {
         if (modemCallbackRegistered || activeDevice == null) {
             return;
@@ -740,11 +722,15 @@ public class Ch934xSerialPlugin implements FlutterPlugin, MethodCallHandler, Act
         }
     }
 
-    /** 主动上抛异常给 Dart 侧。 */
+    /** 主动上抛异常给 Dart 侧。若当前非主线程则自动切换到主线程再发送。 */
     private void pushException(int type, String message, @Nullable String cause) {
         if (!exceptionCallbackEnabled || channel == null) {
             return;
         }
+        if (Looper.myLooper() != Looper.getMainLooper()) {
+            new Handler(Looper.getMainLooper()).post(() -> pushException(type, message, cause));
+            return;
+        }
         Map<String, Object> payload = new HashMap<>();
         payload.put("type", type);
         payload.put("message", message);

lib/ch934x_serial.dart

@@ -107,6 +107,29 @@ class Ch934xSerial {
     }
   }
 
+  /// 多端口并发轮询流：每周期轮询 8 个端口各一次，返回 (portIndex, data) 元组。
+  ///
+  /// 各端口数据互不干扰，消费者端需要用每个端口独立的缓冲区拆分 \r\n 行。
+  /// 不传 [ports] 时默认轮询 0..7 全部端口。
+  Stream<(int, Uint8List)> portDataStream({
+    int chunkSize = 1024,
+    Duration interval = const Duration(milliseconds: 25),
+    List<int> ports = const [0, 1, 2, 3, 4, 5, 6, 7],
+  }) async* {
+    if (chunkSize <= 0) {
+      throw ArgumentError.value(chunkSize, 'chunkSize', '必须大于 0');
+    }
+    while (true) {
+      for (final port in ports) {
+        final chunk = await _platform.read(chunkSize, serialPortIndex: port);
+        if (chunk.isNotEmpty) {
+          yield (port, chunk);
+        }
+      }
+      await Future<void>.delayed(interval);
+    }
+  }
+
   // ---------------------------------------------------------------------------
   // GPIO
   // ---------------------------------------------------------------------------

lib/ch934x_serial_method_channel.dart

@@ -124,14 +124,15 @@ class MethodChannelCh934xSerial extends Ch934xSerialPlatform {
   }
 
   @override
-  Future<Uint8List> read(int length) async {
+  Future<Uint8List> read(int length, {int? serialPortIndex}) async {
     if (length <= 0) {
       return Uint8List(0);
     }
-    final raw = await methodChannel.invokeMethod<Uint8List>(
-      'read',
-      <String, Object>{'length': length},
-    );
+    final args = <String, Object>{'length': length};
+    if (serialPortIndex != null) {
+      args['serialPortIndex'] = serialPortIndex;
+    }
+    final raw = await methodChannel.invokeMethod<Uint8List>('read', args);
     return raw ?? Uint8List(0);
   }
 

lib/ch934x_serial_platform_interface.dart

@@ -75,7 +75,8 @@ abstract class Ch934xSerialPlatform extends PlatformInterface {
   // ---------------------------------------------------------------------------
 
   /// 从串口读取数据(对应 6.1.1 `UsbSerial.read`)。
-  Future<Uint8List> read(int length);
+  /// [serialPortIndex] 可选，指定读取哪个端口的缓冲区；不传则读上次 setActivePort 设置的端口。
+  Future<Uint8List> read(int length, {int? serialPortIndex});
 
   /// 向串口写入数据(对应 6.2.1 `UsbSerial.write`)。
   Future<int> write(Uint8List data);