fix #3

CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.2.2
+
+- change `readBytesOnListen` API
+- add `readBytesOnce`, `openStatus` ...
+
 ## 0.1.2
 
 - add `readOnListen` API

README.md

@@ -37,7 +37,7 @@ port.ReadIntervalTimeout = 10;
 ### Read
 
 ```dart
-print(await ports.readBytes(2));
+port.readBytesOnListen(8, (value) => print(value));
 ```
 
 ### Write

example/lib/main.dart

@@ -29,10 +29,17 @@ class MyHomePage extends StatefulWidget {
 
 class _MyHomePageState extends State<MyHomePage> {
   var ports = <String>[];
+  late SerialPort port;
 
+  String data = '';
   void _getPorts() {
     ports = SerialPort.getAvailablePorts();
-    print(ports);
+    if (ports.isNotEmpty){
+      port = SerialPort(ports[0]);
+      port.readBytesOnListen(8, (value) {data = value.toString(); setState(() {
+
+      });});
+    }
     setState(() {
 
     });
@@ -41,6 +48,7 @@ class _MyHomePageState extends State<MyHomePage> {
     // });
   }
 
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -60,6 +68,7 @@ class _MyHomePageState extends State<MyHomePage> {
               ports.toString(),
               style: Theme.of(context).textTheme.headline4,
             ),
+            Text(data),
           ],
         ),
       ),

example/pubspec.lock

@@ -101,7 +101,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.1.1"
+    version: "0.2.2"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -169,6 +169,6 @@ packages:
       name: win32
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.1.5"
+    version: "2.2.5"
 sdks:
   dart: ">=2.13.0 <3.0.0"

lib/src/serial_port.dart

@@ -35,6 +35,9 @@ class SerialPort {
 
   static final Map<String, SerialPort> _cache = <String, SerialPort>{};
 
+  /// for read loop
+  Timer? _timer;
+
   /// reusable instance using [factory]
   factory SerialPort(
     String portName, {
@@ -205,6 +208,11 @@ class SerialPort {
     _setCommState();
   }
 
+  /// change [isOpened] value if necessary
+  set openStatus(bool status) {
+    _isOpened = status;
+  }
+
   /// [ReadIntervalTimeout]
   ///
   /// The maximum time allowed to elapse before the arrival of the next byte on the communications line,
@@ -268,8 +276,8 @@ class SerialPort {
     _setCommTimeouts();
   }
 
-  /// [readBytes] is an [async] function
-  Future<Uint8List> readBytes(int bytesSize) async {
+  /// [_read] is a fundamental read function/
+  Future<Uint8List> _read(int bytesSize) async {
     final lpBuffer = calloc<Uint16>(bytesSize);
     Uint8List uint8list;
 
@@ -284,38 +292,40 @@ class SerialPort {
     return uint8list;
   }
 
-  /// [readBytesOnListen] can listen operation when function was called.
-  /// It returns a StreamSubscription value
-  /// you can use onData to get data, use onListen and onError and soon.
-  Future<StreamSubscription> readBytesOnListen(
-      int bytesSize, Function(Uint8List value) onData,
-      {required Function() onListen}) async {
-    final lpBuffer = calloc<Uint16>(bytesSize);
-    Uint8List uint8list;
+  /// [readBytesOnce] read data only once.
+  Future<Uint8List> readBytesOnce(int bytesSize) async {
+    if (_timer != null) {
+      throw Exception("You need to remover the read listener!");
+    }
+    return _read(bytesSize);
+  }
 
-    final _closeController = StreamController<String>(
-      onListen: onListen,
-    );
-    final _closeSink = _closeController.sink;
+  /// [readBytesOnListen] can constantly listen data, you can use [onData] to get data.
+  void readBytesOnListen(int bytesSize, Function(Uint8List value) onData,
+      {void onBefore()?, Duration? duration}) async {
+    _cancelTimer();
+    if (onBefore != null) {
+      onBefore();
+    }
+    _timer = Timer.periodic(duration ?? Duration(milliseconds: 20), (timer) {
+      _read(bytesSize).then((value) {
+        if (value.isEmpty) {
+          return;
+        }
+        onData(value);
+      });
+    });
+  }
 
-    ///事件订阅对象
-    StreamSubscription _closeSubscription =
-        _closeController.stream.listen((event) {});
+  /// [removeReadListener] will remove listener in [readBytesOnlisten]
+  void removeReadListener() {
+    _cancelTimer();
+  }
 
-    try {
-      ReadFile(handler!, lpBuffer, bytesSize, _bytesRead, _over);
-    } catch (e) {
-      _closeSink.addError(e.toString());
-    } finally {
-      /// Uint16 need to be casted for real Uint8 data
-      uint8list = lpBuffer.cast<Uint8>().asTypedList(_bytesRead.value);
-      onData(uint8list);
-      free(lpBuffer);
-      _closeController.close();
-      _closeSink.close();
+  void _cancelTimer() {
+    if (_timer != null) {
+      _timer!.cancel();
     }
-
-    return _closeSubscription;
   }
 
   /// [writeBytesFromString] will convert String to ANSI Code corresponding to char

pubspec.lock

@@ -155,6 +155,6 @@ packages:
       name: win32
       url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.2.3"
+    version: "2.2.5"
 sdks:
   dart: ">=2.13.0 <3.0.0"

pubspec.yaml

@@ -1,6 +1,6 @@
 name: serial_port_win32
 description: A SerialPort library using win32 API, for connecting real device by serial port. Now only supports Windows.
-version: 0.1.2
+version: 0.2.2
 homepage: https://github.com/FengChendian/serial_port_win32
 repository: https://github.com/FengChendian/serial_port_win32
 issue_tracker: https://github.com/FengChendian/serial_port_win32/issues
@@ -12,7 +12,7 @@ dependencies:
   ffi: ^1.1.2
   flutter:
     sdk: flutter
-  win32: ^2.1.5
+  win32: ^2.2.5
 
 dev_dependencies:
   flutter_test:

test/serial_port_win32_test.dart

@@ -1,3 +1,5 @@
+import 'dart:io';
+
 import 'package:serial_port_win32/src/serial_port.dart';
 import 'package:win32/win32.dart';
 
@@ -6,10 +8,9 @@ void main() async {
   print(ports);
   if (ports.isNotEmpty) {
     var port = SerialPort(ports[0]);
-    for (var i = 0; i < 100; i++) {
-      print(await port.readBytes(2));
-    }
+    port.readBytesOnListen(8, (value) => print(value));
+    sleep(Duration(seconds: 10));
     // port.BaudRate = CBR_115200;
-    port.close();
+    // port.close();
   }
 }