获取java.io.IOException:读取失败，套接字可能关闭或超时，通过蓝牙打印机打印时读取ret:-1

问题描述

代码仅在第一次正常工作，如果我尝试再次连接它，则会引发此异常:

Code is working fine for first time only, if i am trying to connect it again it is throwing this exception:

这是我用于连接蓝牙打印机的功能:

This is my function for connecting to the bluetooth printer:

public boolean openBT(Context context) throws IOException {
    try {
        // Standard SerialPortService ID
        UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
        mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);
        mBluetoothAdapter.cancelDiscovery();

        mmSocket.connect();

        mmOutputStream = new DataOutputStream(mmSocket.getOutputStream());
        mmInputStream = new DataInputStream(mmSocket.getInputStream());


    } catch (NullPointerException e) {
        e.printStackTrace();
        return false;
    } catch (Exception e) {
         e.printStackTrace();
        return false;

    }

    return true;

}

推荐答案

使用后应关闭套接字:

public boolean openBT(Context context) throws IOException {
try {
    // Standard SerialPortService ID
    UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
    mmSocket = mmDevice.createRfcommSocketToServiceRecord(uuid);
    mBluetoothAdapter.cancelDiscovery();

    mmSocket.connect();

    mmOutputStream = new DataOutputStream(mmSocket.getOutputStream());
    mmInputStream = new DataInputStream(mmSocket.getInputStream());

    mmSocket.close(); //Socket closed
} catch (NullPointerException e) {
    e.printStackTrace();
    return false;
} catch (Exception e) {
     e.printStackTrace();
    return false;

}

return true;}

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