EXAMPLE PROJECT

[mopilo]

While i ran the example project it worked, but as soon as I connect to my thermal printer the app crashes with this log.
Also I'm using the latest version of flutter. 1.54

D/BluetoothAdapter(21892): isEnabled
D/BluetoothAdapter(21892): cancelDiscovery
D/BluetoothAdapter(21892): 241026643: getState(). Returning 12
W/BluetoothAdapter(21892): getBluetoothService() called with no BluetoothManagerCallback
D/FlutterBluePlugin(21892): android.bluetooth.device.action.ACL_CONNECTED
E/FlutterBluePlugin(21892): Methods marked with @UiThread must be executed on the main thread. Current thread: AsyncTask #2
E/FlutterBluePlugin(21892): java.lang.RuntimeException: Methods marked with @UiThread must be executed on the main thread. Current thread: AsyncTask #2
E/FlutterBluePlugin(21892): 	at io.flutter.embedding.engine.FlutterJNI.ensureRunningOnMainThread(FlutterJNI.java:605)
E/FlutterBluePlugin(21892): 	at io.flutter.embedding.engine.FlutterJNI.invokePlatformMessageResponseCallback(FlutterJNI.java:556)
E/FlutterBluePlugin(21892): 	at io.flutter.embedding.engine.dart.DartMessenger$Reply.reply(DartMessenger.java:129)
E/FlutterBluePlugin(21892): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1.success(MethodChannel.java:215)
E/FlutterBluePlugin(21892): 	at io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin.lambda$connect$0(FlutterBluetoothSerialPlugin.java:251)
E/FlutterBluePlugin(21892): 	at io.github.edufolly.flutterbluetoothserial.-$$Lambda$FlutterBluetoothSerialPlugin$52C5RUgoP_r70sgAnP8ZXC1Ysz0.run(lambda)
E/FlutterBluePlugin(21892): 	at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
E/FlutterBluePlugin(21892): 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
E/FlutterBluePlugin(21892): 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
E/FlutterBluePlugin(21892): 	at java.lang.Thread.run(Thread.java:761)
E/FlutterBluePlugin(21892): Reply already submitted
E/FlutterBluePlugin(21892): java.lang.IllegalStateException: Reply already submitted
E/FlutterBluePlugin(21892): 	at io.flutter.embedding.engine.dart.DartMessenger$Reply.reply(DartMessenger.java:124)
E/FlutterBluePlugin(21892): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1.error(MethodChannel.java:220)
E/FlutterBluePlugin(21892): 	at io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin.lambda$connect$0(FlutterBluetoothSerialPlugin.java:254)
E/FlutterBluePlugin(21892): 	at io.github.edufolly.flutterbluetoothserial.-$$Lambda$FlutterBluetoothSerialPlugin$52C5RUgoP_r70sgAnP8ZXC1Ysz0.run(lambda)
E/FlutterBluePlugin(21892): 	at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
E/FlutterBluePlugin(21892): 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
E/FlutterBluePlugin(21892): 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
E/FlutterBluePlugin(21892): 	at java.lang.Thread.run(Thread.java:761)
E/AndroidRuntime(21892): FATAL EXCEPTION: AsyncTask #2
E/AndroidRuntime(21892): Process: io.github.edufolly.flutterbluetoothserialexample, PID: 21892
E/AndroidRuntime(21892): java.lang.IllegalStateException: Reply already submitted
E/AndroidRuntime(21892): 	at io.flutter.embedding.engine.dart.DartMessenger$Reply.reply(DartMessenger.java:124)
E/AndroidRuntime(21892): 	at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1.error(MethodChannel.java:220)
E/AndroidRuntime(21892): 	at io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin.lambda$connect$0(FlutterBluetoothSerialPlugin.java:258)
E/AndroidRuntime(21892): 	at io.github.edufolly.flutterbluetoothserial.-$$Lambda$FlutterBluetoothSerialPlugin$52C5RUgoP_r70sgAnP8ZXC1Ysz0.run(lambda)
E/AndroidRuntime(21892): 	at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
E/AndroidRuntime(21892): 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
E/AndroidRuntime(21892): 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
E/AndroidRuntime(21892): 	at java.lang.Thread.run(Thread.java:761)
I/SurfaceView(21892): updateWindow -- onWindowVisibilityChanged, visibility = 8, this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
I/SurfaceView(21892): 10015476 Changes: creating=false format=false size=false visible=true left=false top=false mUpdateWindowNeeded=false mReportDrawNeeded=false redrawNeeded=false forceSizeChanged=false mVisible=true mRequestedVisible=false, this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
I/SurfaceView(21892): 10015476 Cur surface: Surface(name=null)/@0x9378c8c, this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
I/SurfaceView(21892): 10015476 New surface: Surface(name=null)/@0x9c1afd5, vis=false, frame=Rect(0, 0 - 720, 1280), this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
I/SurfaceView(21892): 10015476 visibleChanged -- surfaceDestroyed, this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
I/SurfaceView(21892): surfaceDestroyed callback +, this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
D/Surface (21892): Surface::disconnect(this=0x9cb8ee00,api=1)
D/GraphicBuffer(21892): unregister, handle(0xa2e87460) (w:720 h:1280 s:720 f:0x1 u:0x000f02)
D/GraphicBuffer(21892): unregister, handle(0xa2e8c010) (w:720 h:1280 s:720 f:0x1 u:0x000f02)
D/GraphicBuffer(21892): unregister, handle(0xa2e8c550) (w:720 h:1280 s:720 f:0x1 u:0x000f02)
I/SurfaceView(21892): surfaceDestroyed callback -, this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
V/SurfaceView(21892): Layout: x=0 y=0 w=720 h=1280, frame=Rect(0, 0 - 720, 1280), this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
D/SurfaceView(21892): 10015476 windowPositionLostRT RT, frameNr = 0
D/Surface (21892): Surface::disconnect(this=0x9cb8e700,api=1)
D/GraphicBuffer(21892): unregister, handle(0xa2e87540) (w:720 h:1280 s:720 f:0x1 u:0x000f02)
D/GraphicBuffer(21892): unregister, handle(0xa2e87700) (w:720 h:1280 s:720 f:0x1 u:0x000f02)
D/GraphicBuffer(21892): unregister, handle(0xa2e8bec0) (w:720 h:1280 s:720 f:0x1 u:0x000f02)
I/SurfaceView(21892): updateWindow -- onDetachedFromWindow, this = io.flutter.view.FlutterView{98d2f4 VFE...... .F...... 0,0-720,1280}
D/WindowClient(21892): Remove from mViews: DecorView@988545c[MainActivity], this = android.view.WindowManagerGlobal@4dd7b19
E/ActivityThread(21892): Activity io.github.edufolly.flutterbluetoothserialexample.MainActivity has leaked IntentReceiver io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin$1$1@8265c89 that was originally registered here. Are you missing a call to unregisterReceiver()?
E/ActivityThread(21892): android.app.IntentReceiverLeaked: Activity io.github.edufolly.flutterbluetoothserialexample.MainActivity has leaked IntentReceiver io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin$1$1@8265c89 that was originally registered here. Are you missing a call to unregisterReceiver()?
E/ActivityThread(21892): 	at android.app.LoadedApk$ReceiverDispatcher.<init>(LoadedApk.java:1201)
E/ActivityThread(21892): 	at android.app.LoadedApk.getReceiverDispatcher(LoadedApk.java:951)
E/ActivityThread(21892): 	at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:1314)
E/ActivityThread(21892): 	at android.app.ContextImpl.registerReceiver(ContextImpl.java:1294)
E/ActivityThread(21892): 	at android.app.ContextImpl.registerReceiver(ContextImpl.java:1288)
E/ActivityThread(21892): 	at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:586)
E/ActivityThread(21892): 	at io.github.edufolly.flutterbluetoothserial.FlutterBluetoothSerialPlugin$1.onListen(FlutterBluetoothSerialPlugin.java:408)
E/ActivityThread(21892): 	at io.flutter.plugin.common.EventChannel$IncomingStreamRequestHandler.onListen(EventChannel.java:191)
E/ActivityThread(21892): 	at io.flutter.plugin.common.EventChannel$IncomingStreamRequestHandler.onMessage(EventChannel.java:170)
E/ActivityThread(21892): 	at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:88)
E/ActivityThread(21892): 	at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:234)
E/ActivityThread(21892): 	at android.os.MessageQueue.nativePollOnce(Native Method)
E/ActivityThread(21892): 	at android.os.MessageQueue.next(MessageQueue.java:328)
E/ActivityThread(21892): 	at android.os.Looper.loop(Looper.java:148)
E/ActivityThread(21892): 	at android.app.ActivityThread.main(ActivityThread.java:6251)
E/ActivityThread(21892): 	at java.lang.reflect.Method.invoke(Native Method)
E/ActivityThread(21892): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1063)
E/ActivityThread(21892): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:924)
I/art     (21892): Enter while loop.
D/OpenGLRenderer(21892): ~CanvasContext() 0xa2ec5000

[AgainPsychoX]

This is the same issue as #36, and it is solved by #35 and the #35 PR is coming very soon so I am closing the issue for now.