Android bluetooth IOException：读取失败，套接字可能关闭或超时，读取ret:-1

Question

我在Android蓝牙API中连接客户端套接字时遇到问题。我已经读过这些帖子了：这篇，这篇，这篇，还有这篇。根据这些帖子，我编写了如下代码，但仍然不起作用：

class MainActivity : AppCompatActivity()
{
    private val bluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
    private var connectThread: ConnectThread? = null

    override fun onCreate(savedInstanceState: Bundle?)
    {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        if (bluetoothAdapter != null)
        {
            if (!bluetoothAdapter.isEnabled)
                bluetoothAdapter.enable()

            val devices = bluetoothAdapter.bondedDevices.toTypedArray()


            if (devices.isNotEmpty())
            {
                connectThread = ConnectThread(devices[0])
                connectThread!!.run()
            }
        }
        else
            Log.i("BluetoothTest", "No bluetooth supported")
    }

    override fun onDestroy()
    {
        super.onDestroy()

        connectThread!!.cancel()
    }

    private inner class ConnectThread(device: BluetoothDevice) : Thread()
    {
        //private val socket = device.createRfcommSocketToServiceRecord(UUID.fromString ("00001101-0000-1000-8000-00805F9B34FB"))
        private val socket = device.javaClass.getMethod("createRfcommSocket", (Int::class
            .javaPrimitiveType)).invoke(device, 2) as BluetoothSocket

        override fun run()
        {
            bluetoothAdapter.cancelDiscovery()
            socket.connect()
        }

        fun cancel()
        {
            socket.close()
        }

    }
}

下面是包含套接字上返回的错误的日志。connect（）：

--------- beginning of crash
05-15 15:59:19.553 24176-24176/com.bluetoothtest E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.bluetoothtest, PID: 24176
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.bluetoothtest/com.bluetoothtest.MainActivity}: java.io.IOException: read failed, socket might closed or timeout, read ret: -1
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
    at android.app.ActivityThread.-wrap11(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
    at android.os.Handler.dispatchMessage(Handler.java:106)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6494)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
 Caused by: java.io.IOException: read failed, socket might closed or timeout, read ret: -1
    at android.bluetooth.BluetoothSocket.readAll(BluetoothSocket.java:685)
    at android.bluetooth.BluetoothSocket.readInt(BluetoothSocket.java:697)
    at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:374)
    at com.bluetoothtest.MainActivity.onCreate(MainActivity.kt:36)
    at android.app.Activity.performCreate(Activity.java:6999)
    at android.app.Activity.performCreate(Activity.java:6990)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2731)

问题似乎出现在Android4.3之后，因为我在Android7.1和8.1上使用的套接字的端口值。有人知道如何在Android上使用蓝牙吗？

Answer 1

最后，根本原因是无法读取套接字的inputStream。这是因为在服务器端没有具有相同UUID的开放套接字。

看见https://android.googlesource.com/platform/frameworks/base//android-8.0.0_r30/core/java/android/bluetooth/BluetoothSocket。Java语言

因此，为了解决这个问题，我们需要一个另一侧具有相同UUID的侦听套接字，对我来说，它是python中的一个树莓：

from bluetooth import *

server_sock=BluetoothSocket( RFCOMM )
server_sock.bind(("",PORT_ANY))
server_sock.listen(1)

port = server_sock.getsockname()[1]

uuid = "YOUR UUID"

advertise_service( server_sock, "SampleServer", service_id = uuid, service_classes = [ uuid, SERIAL_PORT_CLASS ], profiles = [ SERIAL_PORT_PROFILE ])

print("Waiting for connection on RFCOMM channel %d" % port)

client_sock, client_info = server_sock.accept()
print("Accepted connection from ", client_info)

try:
    while True:
        data = client_sock.recv(1024)
        if len(data) == 0: break
        print("received [%s]" % data)
except IOError:
    pass

print("disconnected")

client_sock.close()
server_sock.close()
print("all done")

从…起https://github.com/karulis/pybluez/blob/master/examples/simple/rfcomm-server.py