init

lib/printer_method_channel.dart

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+import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
+
+import 'enums/multi_byte_encoding.dart';
+import 'enums/printer_alignment.dart';
+import 'enums/serial_flow_control.dart';
+import 'enums/serial_parity.dart';
+import 'enums/serial_stop_bits.dart';
+import 'models/printer_exception.dart';
+import 'printer_platform_interface.dart';
+
+/// An implementation of [PrinterPlatform] that uses method channels.
+class MethodChannelPrinter extends PrinterPlatform {
+  /// The method channel used to interact with the native platform.
+  @visibleForTesting
+  final methodChannel = const MethodChannel('printer');
+
+  @override
+  Future<String?> getPlatformVersion() async {
+    final version = await methodChannel.invokeMethod<String>(
+      'getPlatformVersion',
+    );
+    return version;
+  }
+
+  @override
+  Future<int> openComPort({
+    required String portName,
+    required int baudRate,
+    int dataBits = 8,
+    SerialParity parity = SerialParity.none,
+    SerialStopBits stopBits = SerialStopBits.one,
+    SerialFlowControl flowControl = SerialFlowControl.none,
+    bool autoReplyMode = true,
+  }) async {
+    try {
+      final result = await methodChannel.invokeMethod<int>('openComPort', {
+        'portName': portName,
+        'baudRate': baudRate,
+        'dataBits': dataBits,
+        'parity': parity.value,
+        'stopBits': stopBits.value,
+        'flowControl': flowControl.value,
+        'autoReplyMode': autoReplyMode ? 1 : 0,
+      });
+      return result!;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to open COM port',
+        details: e.details,
+      );
+    }
+  }
+
+  @override
+  Future<int> openUsbPort({
+    required String portName,
+    bool autoReplyMode = true,
+  }) async {
+    try {
+      final result = await methodChannel.invokeMethod<int>('openUsbPort', {
+        'portName': portName,
+        'autoReplyMode': autoReplyMode ? 1 : 0,
+      });
+      return result!;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to open USB port',
+        details: e.details,
+      );
+    }
+  }
+
+  @override
+  Future<bool> closePort(int handle) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'closePort',
+        {'handle': handle},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to close port',
+        details: e.details,
+      );
+    }
+  }
+
+  @override
+  Future<bool> isPortOpened(int handle) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'isPortOpened',
+        {'handle': handle},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to check port status',
+        details: e.details,
+      );
+    }
+  }
+
+  @override
+  Future<List<String>> enumComPorts() async {
+    try {
+      final result = await methodChannel.invokeMethod<List>('enumComPorts');
+      return (result ?? []).map((e) => e.toString()).toList();
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to enumerate COM ports',
+        details: e.details,
+      );
+    }
+  }
+
+  @override
+  Future<List<String>> enumUsbPorts() async {
+    try {
+      final result = await methodChannel.invokeMethod<List>('enumUsbPorts');
+      return (result ?? []).map((e) => e.toString()).toList();
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to enumerate USB ports',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Sets the printer to multi-byte encoding mode.
+  @override
+  Future<bool> setMultiByteMode(int handle) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'setMultiByteMode',
+        {'handle': handle},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to set multi-byte mode',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Sets the multi-byte character encoding.
+  @override
+  Future<bool> setMultiByteEncoding(int handle, MultiByteEncoding encoding) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'setMultiByteEncoding',
+        {'handle': handle, 'encoding': encoding.value},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to set multi-byte encoding',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Prints text using UTF-8 encoding.
+  @override
+  Future<bool> printText(int handle, String text) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'printText',
+        {'handle': handle, 'text': text},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to print text',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Sets text alignment.
+  @override
+  Future<bool> setAlignment(int handle, PrinterAlignment alignment) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'setAlignment',
+        {'handle': handle, 'alignment': alignment.value},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to set alignment',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Sets text scale (width and height magnification).
+  @override
+  Future<bool> setTextScale(int handle, {required int widthScale, required int heightScale}) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'setTextScale',
+        {
+          'handle': handle,
+          'widthScale': widthScale,
+          'heightScale': heightScale,
+        },
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to set text scale',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Sets text bold on or off.
+  @override
+  Future<bool> setTextBold(int handle, bool bold) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'setTextBold',
+        {'handle': handle, 'bold': bold ? 1 : 0},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to set text bold',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Sets text underline level.
+  @override
+  Future<bool> setTextUnderline(int handle, int underline) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'setTextUnderline',
+        {'handle': handle, 'underline': underline},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to set text underline',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Feeds paper by specified number of lines.
+  @override
+  Future<bool> feedLine(int handle, int numLines) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'feedLine',
+        {'handle': handle, 'numLines': numLines},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to feed line',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Feeds paper by specified number of dots.
+  @override
+  Future<bool> feedDot(int handle, int numDots) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'feedDot',
+        {'handle': handle, 'numDots': numDots},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to feed dot',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Performs a half cut of the paper.
+  @override
+  Future<bool> halfCutPaper(int handle) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'halfCutPaper',
+        {'handle': handle},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to half cut paper',
+        details: e.details,
+      );
+    }
+  }
+
+  /// Performs a full cut of the paper.
+  @override
+  Future<bool> fullCutPaper(int handle) async {
+    try {
+      final result = await methodChannel.invokeMethod<bool>(
+        'fullCutPaper',
+        {'handle': handle},
+      );
+      return result ?? false;
+    } on PlatformException catch (e) {
+      throw PrinterException(
+        code: e.code,
+        message: e.message ?? 'Failed to full cut paper',
+        details: e.details,
+      );
+    }
+  }
+}