feat: zpl print over bluetooth

android/src/main/java/id/kalanusa/flutter_zsdk/FlutterZsdkPlugin.java

 import id.kalanusa.flutter_zsdk.bluetoothconnectionhandler.BluetoothConnectionHolder;
 import id.kalanusa.flutter_zsdk.bluetoothdiscoveryhandler.BluetoothDiscoveryHandler;
 import id.kalanusa.flutter_zsdk.bluetoothdiscoveryhandler.BluetoothPrinter;
+import id.kalanusa.flutter_zsdk.zplprinthandler.ZplPrintHandler;
 import io.flutter.Log;
 import io.flutter.embedding.engine.dart.DartExecutor;
 import io.flutter.embedding.engine.plugins.FlutterPlugin;
   public BluetoothConnectionHolder bluetoothConnectionHolder;
 
   public BluetoothConnectionHandler bluetoothConnectionHandler;
+  public ZplPrintHandler zplPrintHandler;
 
 
   @Override
     dartExecutor = Objects.requireNonNull(flutterPluginBinding.getFlutterEngine()).getDartExecutor();
     binaryMessenger = dartExecutor.getBinaryMessenger();
 
+
+    bluetoothConnectionHolder = new BluetoothConnectionHolder(null);
   }
 
   @Override
 
   @Override
   public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
-    Log.w("From Native (Android)", "ini di FLutterZsdkPlugin");
+    Log.w("From Native (Android)", "ini di FlutterZsdkPlugin");
 
     switch(call.method) {
       case "bluetoothOpenConnection":
       case "isConnected":
       case "bluetoothCloseConnection":
         if (bluetoothConnectionHandler == null) {
-          bluetoothConnectionHandler = new BluetoothConnectionHandler(bluetoothConnectionHolder);
+          bluetoothConnectionHandler = new BluetoothConnectionHandler();
         }
 
         bluetoothConnectionHandler.handle(call, result);
         break;
 
+      case "printZplOverBluetooth":
+        if (zplPrintHandler == null) {
+          zplPrintHandler = new ZplPrintHandler();
+        }
+
+        zplPrintHandler.handle(call, result);
+        break;
     }
   }
 

android/src/main/java/id/kalanusa/flutter_zsdk/bluetoothconnectionhandler/BluetoothConnectionHandler.java

 import io.flutter.plugin.common.MethodChannel;
 
 public class BluetoothConnectionHandler {
-    BluetoothConnectionHolder bluetoothConnectionHolder;
     String macAddress;
 
-    public BluetoothConnectionHandler(BluetoothConnectionHolder bluetoothConnectionHolder) {
-        this.bluetoothConnectionHolder = bluetoothConnectionHolder;
-    }
-
     public void handle(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
 
         switch (call.method) {
             case "bluetoothOpenConnection":
-                if (bluetoothConnectionHolder == null) {
-                    bluetoothConnectionHolder = new BluetoothConnectionHolder(new BluetoothConnectionInsecure(call.argument("macAddress")));
+                if (BluetoothConnectionHolder.connection == null) {
+                    BluetoothConnectionHolder.updateConnection(new BluetoothConnectionInsecure(call.argument("macAddress")));
                 }
 
                 openConnection(result);
             public void run() {
                 try {
                     Looper.prepare();
-                    bluetoothConnectionHolder.connection.open();
+                    BluetoothConnectionHolder.connection.open();
                     Looper.myLooper().quit();
                     result.success(null);
                     Log.w("From Native (Android)", "open connection finished");
         new Thread(new Runnable() {
             @Override
             public void run() {
-                boolean isConnected = bluetoothConnectionHolder.connection.isConnected();
+                boolean isConnected = BluetoothConnectionHolder.connection.isConnected();
 
                 result.success(isConnected);
 
             @Override
             public void run() {
                 try {
-                    bluetoothConnectionHolder.connection.close();
+                    BluetoothConnectionHolder.connection.close();
                     result.success(null);
                 } catch (ConnectionException e) {
                     Log.w("From Native (Android)", "something went wrong when closing connection");

android/src/main/java/id/kalanusa/flutter_zsdk/bluetoothconnectionhandler/BluetoothConnectionHolder.java

 import com.zebra.sdk.comm.Connection;
 
 public class BluetoothConnectionHolder {
-    public Connection connection;
+    static public Connection connection;
 
     public BluetoothConnectionHolder(@NonNull Connection connection) {
         this.connection = connection;
     }
 
-    public void updateConnection(@NonNull Connection connection) {
-        this.connection = connection;
+    static public void updateConnection(@NonNull Connection connection) {
+        BluetoothConnectionHolder.connection = connection;
     }
 }

android/src/main/java/id/kalanusa/flutter_zsdk/zplprinthandler/ZplPrintHandler.java

+package id.kalanusa.flutter_zsdk.zplprinthandler;
+
+import androidx.annotation.NonNull;
+
+import com.zebra.sdk.comm.ConnectionException;
+
+import id.kalanusa.flutter_zsdk.bluetoothconnectionhandler.BluetoothConnectionHandler;
+import id.kalanusa.flutter_zsdk.bluetoothconnectionhandler.BluetoothConnectionHolder;
+import io.flutter.Log;
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
+
+public class ZplPrintHandler {
+
+    public void handle(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
+        printZplOverBluetooth(result);
+    }
+
+
+    public void printZplOverBluetooth(@NonNull MethodChannel.Result result) {
+        new Thread(new Runnable() {
+            @Override
+            public void run() {
+//                Log.w("From Native (Android)", "isConnected from zplPrinterHandler " + BluetoothConnectionHolder.connection.isConnected() );
+                try {
+                    String zplData = "^XA^PW624^LL800^FO20,20^A0N,25,25^FDThis is a ZPL test.^FS^FO20,60^BQ , 60,10 , , , A ^FD 1234ABC.^FS^XZ";
+                    BluetoothConnectionHolder.connection.write(zplData.getBytes());
+                } catch (ConnectionException e) {
+                    Log.w("From Native (Android)", "something went wrong when sending data to printer");
+                    result.error("WRITE_ERROR", "Something went wrong when sending data to printer", e.getMessage());
+                }
+            }
+        }).start();
+    }
+}

example/lib/main.dart

     setState(() {});
   }
 
+  Future<void> printZplOverBluetooth() async {
+    print('invoked printZplOverBluetooth from dart');
+    try {
+      await _flutterZsdkPlugin.printZplOverBluetooth();
+      print('printZplOverBluetooth successfully from dart');
+      
+    } on FlutterZsdkException catch (e) {
+      inspect(e);
+      showSnackBar(e.message);
+
+    } catch (e) {
+      inspect(e);
+      showSnackBar('Unexpected error when send data to printers');
+    }
+
+    setState(() {});
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
             ),
             SizedBox(height: 20),
 
+            ElevatedButton(
+              child: Text('Print zpl over bluetooth'),
+              onPressed: _connectedPrinter == null ? null : printZplOverBluetooth,
+            ),
+            SizedBox(height: 20),
+
             ElevatedButton(
               child: Text('Check connection status'),
               onPressed: () async {

lib/flutter_zsdk.dart

   Future<void> closeConnection() {
     return FlutterZsdkPlatform.instance.closeConnection();
   }
+
+  Future<void> printZplOverBluetooth() {
+    return FlutterZsdkPlatform.instance.printZplOverBluetooth();
+  }
 }

lib/src/flutter_zsdk_method_channel.dart

       throw FlutterZsdkException("Failed to close connection to printer: $e");
     }
   }
+
+  @override
+  Future<void> printZplOverBluetooth() async {
+    try {
+      await methodChannel.invokeMethod('printZplOverBluetooth');
+    } catch (e) {
+      throw FlutterZsdkException("Failed to print ZPL over Bluetooth: $e");
+    }
+  }
 }

lib/src/flutter_zsdk_platform_interface.dart

   Future<void> closeConnection() {
     throw UnimplementedError('closeConnection() has not been implemented.');
   }
+
+  Future<void> printZplOverBluetooth() {
+    throw UnimplementedError('printZplOverBluetooth() has not been implemented.');
+  }
 }