单例模式

.idea/workspace.xml

@@ -2,25 +2,8 @@
 <project version="4">
   <component name="ChangeListManager">
     <list default="true" id="2f8e3712-04e2-429a-bcea-c8db1a54008e" name="默认变更列表" comment="">
-      <change afterPath="$PROJECT_DIR$/android/libs/Sewoo_Android_1109.jar" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/android/src/main/java/com/dj/printer/dj_printer/AsPrint.java" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/android/src/main/java/com/dj/printer/dj_printer/Blutooth.java" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/lib/src/device_model.dart" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/lib/src/status_enum.dart" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/.idea/libraries/Dart_SDK.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/libraries/Dart_SDK.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/android/build.gradle" beforeDir="false" afterPath="$PROJECT_DIR$/android/build.gradle" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/android/src/main/AndroidManifest.xml" beforeDir="false" afterPath="$PROJECT_DIR$/android/src/main/AndroidManifest.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/android/src/main/java/com/dj/printer/dj_printer/DjPrinterPlugin.java" beforeDir="false" afterPath="$PROJECT_DIR$/android/src/main/java/com/dj/printer/dj_printer/DjPrinterPlugin.java" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/dj_printer.iml" beforeDir="false" afterPath="$PROJECT_DIR$/dj_printer.iml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/android/app/build.gradle" beforeDir="false" afterPath="$PROJECT_DIR$/example/android/app/build.gradle" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/android/app/src/main/AndroidManifest.xml" beforeDir="false" afterPath="$PROJECT_DIR$/example/android/app/src/main/AndroidManifest.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/lib/main.dart" beforeDir="false" afterPath="$PROJECT_DIR$/example/lib/main.dart" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/pubspec.lock" beforeDir="false" afterPath="$PROJECT_DIR$/example/pubspec.lock" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/pubspec.yaml" beforeDir="false" afterPath="$PROJECT_DIR$/example/pubspec.yaml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/lib/dj_printer.dart" beforeDir="false" afterPath="$PROJECT_DIR$/lib/dj_printer.dart" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/pubspec.lock" beforeDir="false" afterPath="$PROJECT_DIR$/pubspec.lock" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/test/dj_printer_test.dart" beforeDir="false" afterPath="$PROJECT_DIR$/test/dj_printer_test.dart" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />

lib/dj_printer.dart

@@ -4,6 +4,11 @@ import 'package:dj_printer/src/status_enum.dart';
 import 'package:flutter/services.dart';
 
 class DjPrinter {
+  static late final DjPrinter _instance = DjPrinter._();
+
+  DjPrinter._();
+
+  factory DjPrinter() => _instance;
   static const MethodChannel _channel = MethodChannel('dj_printer');
   static const EventChannel _deviceChannel =
       EventChannel("com.discovery.devices");