Connect success then disconnect immediately

[mtaweel]

The bluethooth thermal printer device is found successfully, but when I click on connect it connects for a 1 sec and then disconnects immediately, here are the logs:

/flutter (25274): ******************* cur device status: 12
D/BluetoothPrintPlugin(25274): start scan 
D/BluetoothAdapter(25274): isLeEnabled(): ON
D/BluetoothLeScanner(25274): onScannerRegistered() - status=0 scannerId=8 mScannerId=0
V/PhoneWindow(25274): DecorView setVisiblity: visibility = 0, Parent = android.view.ViewRootImpl@3bc37fa, this = DecorView@58e31ab[MainActivity]
D/BluetoothAdapter(25274): isLeEnabled(): ON
D/BluetoothPrintPlugin(25274): start scan 
/BluetoothAdapter(25274): isLeEnabled(): ON
D/BluetoothLeScanner(25274): onScannerRegistered() - status=0 scannerId=8 mScannerId=0
V/PhoneWindow(25274): DecorView setVisiblity: visibility = 0, Parent = android.view.ViewRootImpl@3bc37fa, this = DecorView@58e31ab[MainActivity]
D/BluetoothAdapter(25274): isLeEnabled(): ON
D/BluetoothPrintPlugin(25274): start scan 
D/BluetoothAdapter(25274): isLeEnabled(): ON
D/BluetoothLeScanner(25274): onScannerRegistered() - status=0 scannerId=8 mScannerId=0
V/PhoneWindow(25274): DecorView setVisiblity: visibility = 0, Parent = android.view.ViewRootImpl@3bc37fa, this = DecorView@58e31ab[MainActivity]
D/BluetoothAdapter(25274): isLeEnabled(): ON
/BluetoothAdapter(25274): getBluetoothService() called with no BluetoothManagerCallback
D/BluetoothPrintPlugin(25274): stateStreamHandler, current action: android.bluetooth.device.action.ACL_CONNECTED
I/flutter (25274): ******************* cur device status: 1
W/System.err(25274): java.io.IOException: read failed, socket might closed or timeout, read ret: -1
W/System.err(25274): 	at android.bluetooth.BluetoothSocket.readAll(BluetoothSocket.java:758)
W/System.err(25274): 	at android.bluetooth.BluetoothSocket.waitSocketSignal(BluetoothSocket.java:711)
W/System.err(25274): 	at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:409)
W/System.err(25274): 	at com.gprinter.io.BluetoothPort.openPort(BluetoothPort.java:58)
W/System.err(25274): 	at com.example.bluetooth_print.DeviceConnFactoryManager.openPort(DeviceConnFactoryManager.java:150)
W/System.err(25274): 	at com.example.bluetooth_print.BluetoothPrintPlugin$3.run(BluetoothPrintPlugin.java:346)
W/System.err(25274): 	at com.example.bluetooth_print.ThreadPool$1.run(ThreadPool.java:78)
W/System.err(25274): 	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
W/System.err(25274): 	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
W/System.err(25274): 	at java.lang.Thread.run(Thread.java:923)
D/BluetoothPrintPlugin(25274): stateStreamHandler, current action: android.bluetooth.device.action.ACL_DISCONNECTED
I/flutter (25274): ******************* cur device status: 0

[danilocatalanoapsystem]

I have the same problem too

[danilocatalanoapsystem]

I managed to solve the problem. I had changed an image. In my opinion the printer memory or bluetooth is unable to receive or store data internally.

[mtaweel]

@danilocatalanoapsystem What image? Can you please elaborate more, i'm running the example app. When I search for the printer, I found it, but when I click on connect, it connects for 1 sec and then disconnects throwing the above Exception. I don't print anything yet. It just disconnects directly after connect

[jboffog]

same problem here:

D/BluetoothPrintPlugin(25057): start scan
D/BluetoothAdapter(25057): isLeEnabled(): ON
D/BluetoothLeScanner(25057): onScannerRegistered() - status=0 scannerId=10 mScannerId=0
D/BluetoothSocket(25057): mRstricteState = false
D/BluetoothAdapter(25057): isLeEnabled(): ON
D/BluetoothSocket(25057): startRecord connect mPfd = {ParcelFileDescriptor: java.io.FileDescriptor@3de5e6e}fd = 132
E/DeviceConnFactoryManager(25057): ******************* wait read
D/BluetoothSocket(25057): close() this: android.bluetooth.BluetoothSocket@c4bb3a5, channel: 6, mSocketIS: android.net.LocalSocketImpl$SocketInputStream@395f37a, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream@164072b, mSocket: android.net.LocalSocket@8085788 impl:android.net.LocalSocketImpl@168e521 fd:java.io.FileDescriptor@3de5e6e, mSocketState: CONNECTED
D/BluetoothSocket(25057): removeChangeCallback
D/BluetoothSocket(25057): startRecord close mPfd = {ParcelFileDescriptor: java.io.FileDescriptor@3de5e6e}fd = 132
W/System.err(25057): java.io.IOException: bt socket closed, read return: -1
W/System.err(25057): 	at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:620)
W/System.err(25057): 	at android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:91)
W/System.err(25057): 	at java.io.InputStream.read(InputStream.java:205)
W/System.err(25057): 	at com.gprinter.io.BluetoothPort.readData(BluetoothPort.java:130)
D/BluetoothSocket(25057): close() this: android.bluetooth.BluetoothSocket@c4bb3a5, channel: 6, mSocketIS: android.net.LocalSocketImpl$SocketInputStream@395f37a, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream@164072b, mSocket: null, mSocketState: CLOSED
W/System.err(25057): 	at com.example.bluetooth_print.DeviceConnFactoryManager.readDataImmediately(DeviceConnFactoryManager.java:308)
D/BluetoothSocket(25057): close() this: android.bluetooth.BluetoothSocket@c4bb3a5, channel: 6, mSocketIS: android.net.LocalSocketImpl$SocketInputStream@395f37a, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream@164072b, mSocket: null, mSocketState: CLOSED
W/System.err(25057): 	at com.example.bluetooth_print.DeviceConnFactoryManager$PrinterReader.run(DeviceConnFactoryManager.java:387)
E/BluetoothPort(25057): connection device is lost
E/DeviceConnFactoryManager(25057): ******************* read 0

[biloo-dev]

Is there any update on this issue?
I have the same problem with the pin code??
Please let us know if it has been resolved. Thanks!

[ebecenek]

I am trying to solve the same problem. I can list and select the printer but when I tap connect, it's connecting but immediatly after connection breaks. I'm using a Zebra printer with an Android 12 tablet.

I would appriciate any help.

D/BluetoothPrintPlugin( 4207): stateStreamHandler, current action: android.bluetooth.device.action.ACL_CONNECTED I/flutter ( 4207): ******************* cur device status: 1 E/DeviceConnFactoryManager( 4207): ******************* wait read D/BluetoothSocket( 4207): close() this: android.bluetooth.BluetoothSocket@43cb4e9, channel: 1, mSocketIS: android.net.LocalSocketImpl$SocketInputStream@22e356e, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream@308740fmSocket: android.net.LocalSocket@902c9c impl:android.net.LocalSocketImpl@7a2b6a5 fd:java.io.FileDescriptor@c8c3a7a, mSocketState: CONNECTED W/System.err( 4207): java.io.IOException: bt socket closed, read return: -1 D/BluetoothSocket( 4207): close() this: android.bluetooth.BluetoothSocket@43cb4e9, channel: 1, mSocketIS: android.net.LocalSocketImpl$SocketInputStream@22e356e, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream@308740fmSocket: null, mSocketState: CLOSED W/System.err( 4207): at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:751) D/BluetoothSocket( 4207): close() this: android.bluetooth.BluetoothSocket@43cb4e9, channel: 1, mSocketIS: android.net.LocalSocketImpl$SocketInputStream@22e356e, mSocketOS: android.net.LocalSocketImpl$SocketOutputStream@308740fmSocket: null, mSocketState: CLOSED W/System.err( 4207): at android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:91) W/System.err( 4207): at java.io.InputStream.read(InputStream.java:101) W/System.err( 4207): at com.gprinter.io.BluetoothPort.readData(BluetoothPort.java:130) W/System.err( 4207): at com.example.bluetooth_print.DeviceConnFactoryManager.readDataImmediately(DeviceConnFactoryManager.java:308) W/System.err( 4207): at com.example.bluetooth_print.DeviceConnFactoryManager$PrinterReader.run(DeviceConnFactoryManager.java:387) E/BluetoothPort( 4207): connection device is lost

[AmanBhangre]

I am facing the same issue. Any updates would help.

[krunalagrawal]

I am also facing this issue in old Android version. Printer connected for 1 sec and then disconnected.

[AmanBhangre]

I am also facing this issue in old Android version. Printer connected for 1 sec and then disconnected.

For me, the device was supporting V2 Bluetooth for android but the package is only supporting V4. I switched to this package named flutter_blue_plus package and it worked for me

[DedeSnrwn13]

I am also facing this issue in old Android version. Printer connected for 1 sec and then disconnected.

Yes, same here

[nattysplace]

Same thing happeing on my code as well. I dont know if there is a difference on the device being connected like a BLE printer

[ebecenek]

For those who still looking for a solution, I've found it not in this package but in ZEBRA jar. (ZSDK_ANDROID_API.jar)
I downloaded Zebra SDK Demo project (ZSDK_DemosAndroid) and took out the JAR file to use in my own project.
I removed bluetooth_print completely and used methods from JAR file to wrote my own code in java side of flutter project.
It worked just fine.