java.io.ioException : read failed, 套接字可能关闭或超时 Java Android Studio

Question

我正在 android studio 中使用蓝牙套接字连接到蓝牙设备，当我尝试连接套接字时出现异常:Java.IOException 读取失败，套接字可能关闭或超时 这是我的代码:

    boolean connected=true;
    try {
        socket = device.createRfcommSocketToServiceRecord(PORT_UUID);
        socket.connect();
    } catch (IOException e) {
        e.printStackTrace();
        connected=false;
    }
    if(connected)
    {
        try {
            outputStream=socket.getOutputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }
        try {
            inputStream=socket.getInputStream();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

Answer 1

这对我有用。看看下面的类(class) (https://github.com/aosp-mirror/platform_frameworks_base/blob/android-4.3_r2/core/java/android/bluetooth/BluetoothDevice.java#L1037)。在这种情况下，重新启动 SPP 设备(拔掉/插入)会有所帮助。

下面是通过套接字配对设备的完整类。尽管您可以创建不同的类，因为它有点嵌套。

    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.lang.reflect.Method;
    import java.util.List;
    import java.util.UUID;

    import android.bluetooth.BluetoothAdapter;
    import android.bluetooth.BluetoothDevice;
    import android.bluetooth.BluetoothSocket;
    import android.util.Log;

public class BluetoothConnector {

    private BluetoothSocketWrapper bluetoothSocket;
    private BluetoothDevice device;
    private boolean secure;
    private BluetoothAdapter adapter;
    private List<UUID> uuidCandidates;
    private int candidate;


    /**
     * @param device         the device
     * @param secure         if connection should be done via a secure socket
     * @param adapter        the Android BT adapter
     * @param uuidCandidates a list of UUIDs. if null or empty, the Serial PP id is used
     */
    public BluetoothConnector(BluetoothDevice device, boolean secure, BluetoothAdapter adapter,
                              List<UUID> uuidCandidates) {
        this.device = device;
        this.secure = secure;
        this.adapter = adapter;
        this.uuidCandidates = uuidCandidates;

        if (this.uuidCandidates == null || this.uuidCandidates.isEmpty()) {
            this.uuidCandidates = new ArrayList<UUID>();
            this.uuidCandidates.add(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
        }
    }

    public BluetoothSocketWrapper connect() throws IOException {
        boolean success = false;
        while (selectSocket()) {
            adapter.cancelDiscovery();

            try {
                bluetoothSocket.connect();
                success = true;
                break;
            } catch (IOException e) {
                //try the fallback
                try {
                    bluetoothSocket = new FallbackBluetoothSocket(bluetoothSocket.getUnderlyingSocket());
                    Thread.sleep(500);
                    bluetoothSocket.connect();
                    success = true;
                    break;
                } catch (FallbackException e1) {
                    Log.w("BT", "Could not initialize FallbackBluetoothSocket classes.", e);
                } catch (InterruptedException e1) {
                    Log.w("BT", e1.getMessage(), e1);
                } catch (IOException e1) {
                    Log.w("BT", "Fallback failed. Cancelling.", e1);
                }
            }
        }

        if (!success) {
            throw new IOException("Could not connect to device: " + device.getAddress());
        }

        return bluetoothSocket;
    }

    private boolean selectSocket() throws IOException {
        if (candidate >= uuidCandidates.size()) {
            return false;
        }

        BluetoothSocket tmp;
        UUID uuid = uuidCandidates.get(candidate++);

        Log.i("BT", "Attempting to connect to Protocol: " + uuid);
        if (secure) {
            tmp = device.createRfcommSocketToServiceRecord(uuid);
        } else {
            tmp = device.createInsecureRfcommSocketToServiceRecord(uuid);
        }
        bluetoothSocket = new NativeBluetoothSocket(tmp);

        return true;
    }

    public static interface BluetoothSocketWrapper {

        InputStream getInputStream() throws IOException;

        OutputStream getOutputStream() throws IOException;

        String getRemoteDeviceName();

        void connect() throws IOException;

        String getRemoteDeviceAddress();

        void close() throws IOException;

        BluetoothSocket getUnderlyingSocket();

    }


    public static class NativeBluetoothSocket implements BluetoothSocketWrapper {

        private BluetoothSocket socket;

        public NativeBluetoothSocket(BluetoothSocket tmp) {
            this.socket = tmp;
        }

        @Override
        public InputStream getInputStream() throws IOException {
            return socket.getInputStream();
        }

        @Override
        public OutputStream getOutputStream() throws IOException {
            return socket.getOutputStream();
        }

        @Override
        public String getRemoteDeviceName() {
            return socket.getRemoteDevice().getName();
        }

        @Override
        public void connect() throws IOException {
            socket.connect();
        }

        @Override
        public String getRemoteDeviceAddress() {
            return socket.getRemoteDevice().getAddress();
        }

        @Override
        public void close() throws IOException {
            socket.close();
        }

        @Override
        public BluetoothSocket getUnderlyingSocket() {
            return socket;
        }

    }

    public class FallbackBluetoothSocket extends NativeBluetoothSocket {

        private BluetoothSocket fallbackSocket;

        public FallbackBluetoothSocket(BluetoothSocket tmp) throws FallbackException {
            super(tmp);
            try {
                Class<?> clazz = tmp.getRemoteDevice().getClass();
                Class<?>[] paramTypes = new Class<?>[]{Integer.TYPE};
                Method m = clazz.getMethod("createRfcommSocket", paramTypes);
                Object[] params = new Object[]{Integer.valueOf(1)};
                fallbackSocket = (BluetoothSocket) m.invoke(tmp.getRemoteDevice(), params);
            } catch (Exception e) {
                throw new FallbackException(e);
            }
        }

        @Override
        public InputStream getInputStream() throws IOException {
            return fallbackSocket.getInputStream();
        }

        @Override
        public OutputStream getOutputStream() throws IOException {
            return fallbackSocket.getOutputStream();
        }


        @Override
        public void connect() throws IOException {
            fallbackSocket.connect();
        }


        @Override
        public void close() throws IOException {
            fallbackSocket.close();
        }

    }

    public static class FallbackException extends Exception {

        /**
         *
         */
        private static final long serialVersionUID = 1L;

        public FallbackException(Exception e) {
            super(e);
        }

    }
}