Android-蓝牙打印机未完成打印，但抛出IOException:套接字已关闭

Question

我有一个将数据（文本和图像）打印到热敏打印机的应用程序。

我的问题是，每当我打印冗长的数据时，打印输出就会被剪切，并且在我打印的try-catch语句中会抛出一个IOException: Socket Closed。

这是我打印数据的部分：

protected void simpleComm(Integer port){
    //InputStream tmpIn = null;
    byte[] buffer = new byte[3]; //{65,65,53,53,49,52,65,66,67,68};
    buffer[0] = (byte) 0x08;
    buffer[1] = (byte) 0x99;
    buffer[2] = (byte) 0x04;
    OutputStream tmpOut;// = null;    
    bluetoothAdapter.cancelDiscovery();
    Log.d(this.toString(), "Port = " + port);
    try {

        UUID uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
        Method m = blueToothDevice.getClass().getMethod("createRfcommSocket", new Class[] { int.class });
        socket = (BluetoothSocket) m.invoke(blueToothDevice, port);
        //socket = mmDevice.createRfcommSocketToServiceRecord(uuid);
        // assert (socket != null) : "Socket is Null";
        socket.connect();
        try {
            Log.d(this.toString(),"************ CONNECTION SUCCEES! *************");
            try{
                //tmpIn=socket.getInputStream();
                tmpOut = socket.getOutputStream();
                //mmInStream = tmpIn;
                mmOutStream = tmpOut;
            }
            catch(Exception ex){
                Log.e(this.toString(), "Exception " + ex.getMessage());
            }
            //TODO print sequence starts here
            image = "logo";
            print_image(Environment.getExternalStorageDirectory().toString() + "/LOGO.png");
            byte[] arrayOfByte1 = { 27, 33, 0 };
            byte[] format = { 27, 33, 0 };
            mmOutStream.write((newline).getBytes("US-ASCII"));

            //bold
            format[2] = ((byte)(0x0 | arrayOfByte1[2]));  
            //width
            format[2] = ((byte)(0x12 | arrayOfByte1[2]));
            //height
            format[2] = ((byte)(0x8 | arrayOfByte1[2]));
            mmOutStream.write(format);

            for(int i = 0 ; i < orderListForPrinting.size(); i++ ){
                mmOutStream.write(((List.get(i)).getBytes("US-ASCII")));
            }

            //bold
            format[2] = ((byte)(0x8 | arrayOfByte1[2]));  
            //width
            format[2] = ((byte)(0x8 | arrayOfByte1[2]));
            //height
            format[2] = ((byte)(0x8 | arrayOfByte1[2]));
            mmOutStream.write(format);
            mmOutStream.write((newline).getBytes("US-ASCII"));

            printSignature();
            //bold
            format[2] = ((byte)(0x8 | arrayOfByte1[2]));  
            //width
            format[2] = ((byte)(0x8 | arrayOfByte1[2]));
            //height
            format[2] = ((byte)(0x8 | arrayOfByte1[2]));
            mmOutStream.write(format);
            mmOutStream.write(( name + "                  " + newline + newline).getBytes("US-ASCII"));                
        }
        finally{
            orderList = new ArrayList<TotalOrderClass>();
            orderListForPrinting = new ArrayList<String>();
            socket.close();
            mmOutStream.flush();
        }
    } 
    catch (IOException ex){
        Log.e(this.toString(), "IOException: " + ex.getMessage());
    } 
    catch (NoSuchMethodException ex){
        Log.e(this.toString(), "NoSuchMethodException: " + ex.getMessage());
    } 
    catch (IllegalAccessException ex){
        Log.e(this.toString(), "IllegalAccessException: " + ex.getMessage());
    } 
    catch (InvocationTargetException ex){
        Log.e(this.toString(),"InvocationTargetException: " + ex.getMessage());
    }
}

这是我的打印签名功能，它类似于我用来打印徽标的功能。

private void printSignature() {
    //TODO print signature here
    convertBitmap(signature);
    try{
        mmOutStream.write(PrinterCommands.SET_LINE_SPACING_24);
        int offset = 0;
        while (offset < signature.getHeight()) {
            mmOutStream.write(PrinterCommands.SELECT_BIT_IMAGE_MODE_SIGNATURE);
            for (int x = 0; x < signature.getWidth(); ++x) {
                for (int k = 0; k < 3; ++k) {
                    byte slice = 0;
                    for (int b = 0; b < 8; ++b) {
                        int y = (((offset / 8) + k) * 8) + b;
                        int i = (y * signature.getWidth()) + x;
                        boolean v = false;
                        if (i < dots.length()) {
                            v = dots.get(i);
                        }
                        slice |= (byte) ((v ? 1 : 0) << (7 - b));
                    }
                    mmOutStream.write(slice);
                }
            }
            offset += 24;
            mmOutStream.write(PrinterCommands.FEED_LINE);
        }
        mmOutStream.write(PrinterCommands.SET_LINE_SPACING_30);
    }
    catch (IOException e) {
        Toast.makeText(getApplicationContext(), "Catch on to print signature stuff", Toast.LENGTH_LONG).show();
        e.printStackTrace();
    }
}

ConvertBitmap函数：

public String convertBitmap(Bitmap inputBitmap) {
    int mWidth = inputBitmap.getWidth();
    int mHeight = inputBitmap.getHeight();
    convertArgbToGrayscale(inputBitmap, mWidth, mHeight);
    String mStatus = "ok";
    return mStatus;
}

convertArgbToGrayScale函数：

private void convertArgbToGrayscale(Bitmap bmpOriginal, int width,
        int height) {
    int pixel;
    int k = 0;
    int B = 0, G = 0, R = 0;
    dots = new BitSet();
    try {
        for (int x = 0; x < height; x++) {
            for (int y = 0; y < width; y++) {
                // get one pixel color
                pixel = bmpOriginal.getPixel(y, x);
                // retrieve color of all channels
                R = Color.red(pixel);
                G = Color.green(pixel);
                B = Color.blue(pixel);
                // take conversion up to one single value by calculating
                // pixel intensity.
                R = G = B = (int) (0.299 * R + 0.587 * G + 0.114 * B);
                // set bit into bitset, by calculating the pixel's luma
                if (R < 55) {                       
                    dots.set(k);//this is the bitset that i'm printing
                }
                k++;
            }

        }

    } catch (Exception e) {
        Toast.makeText(getApplicationContext(), "Catch on to Grayscale stuff", Toast.LENGTH_LONG).show();
    }
}

我现在的问题是，在调用printSignature（）函数后，打印机停止打印，套接字关闭，这就是为什么我得到IOException:socket closed错误的原因。

我已经运行了好几次这个函数，我不知道为什么套接字会关闭，因为我只在try-catch的finally子句关闭套接字。

有什么想法吗？

Answer 1

如果将Thread.sleep(2000)放在socket.close()之前会发生什么？

我在蓝牙SPP上工作，我也遇到了同样的问题（套接字在数据传输结束前关闭）。我认为socket.close()的广播比数据的传输快，那么当关闭请求发送时，BT打印机不会分析所有数据

Answer 2

我所做的是，在每个.Write()之后放入一个Thread.sleep(x)，其中x是输出字符串中的字符数，这在代码中可能有所不同，但程序在关闭之前必须等待的时间与打印的字符数（或行数）成比例。