Java Android通过蓝牙连接到设备

Question

我尝试连接到蓝牙使用的设备。当我尝试连接时，我得到：

java.io.IOException: read failed, socket might be closed or timeout, read ret: -1

我这样做：

BluetoothSocket mmSocket;

 public ConnectThread(BluetoothDevice device) {
            mmDevice = device;
            BluetoothSocket tmp = null;
            // Get a BluetoothSocket for a connection with the
            // given BluetoothDevice
            try {
                tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
            } catch (IOException e) {
            }
            mmSocket = tmp;
        }

当我这样做时：

mmSocket.connect();

我有例外

这是我的连接线程：

private class ConnectThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final BluetoothDevice mmDevice;

    public ConnectThread(BluetoothDevice device) {
        mmDevice = device;
        BluetoothSocket tmp = null;
        // Get a BluetoothSocket for a connection with the
        // given BluetoothDevice
        try {
            tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
        } catch (IOException e) {
        }
        mmSocket = tmp;
    }

    public void run() {
        setName("ConnectThread");
        // Always cancel discovery because it will slow down a connection
        mAdapter.cancelDiscovery();
        // Make a connection to the BluetoothSocket
        try {
            // This is a blocking call and will only return on a
            // successful connection or an exception
            mmSocket.connect();
        } catch (IOException e) {
            e.printStackTrace();
            connectionFailed();
            // Close the socket
            try {
                mmSocket.close();
            } catch (IOException e2) {
                e2.printStackTrace();
            }
            // Start the service over to restart listening mode
            BluetoothChatService.this.start();
            return;
        }
        // Reset the ConnectThread because we're done
        synchronized (BluetoothChatService.this) {
            mConnectThread = null;
        }
        // Start the connected thread
        connected(mmSocket, mmDevice);
    }

    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}