没有打印服务预览的打印答案

【问题标题】：Printing without print service preview没有打印服务预览的打印
【发布时间】：2018-06-04 20:54:59
【问题描述】：

我想在我的应用程序中按下按钮并将 pdf 文档发送到打印机直接打印（不显示来自打印框架 Android 4.4 的系统 android 预览）。我该怎么做？我试图通过 Socket 连接到打印机。没问题，没有例外，但我的打印机没有响应，也没有打印任何内容。

也许我需要在手机上为混凝土打印机设置驱动程序？但是怎么做，我在哪里可以得到这样的驱动程序？

已编辑

【问题讨论】：

标签： java android printing android-print-framework

【解决方案1】：

我编写了一个类来帮助将 PDF 文件直接打印到网络打印机，并提供其 IP。它应该可以在大多数打印机上工作，只要它们支持 PJL 命令。

public class PrintService {

    private static PrintListener printListener;

    public enum PaperSize {
        A4,
        A5
    }

    public static void printPDFFile(final String printerIP, final int printerPort,
                                    final File file, final String filename, final PaperSize paperSize, final int copies) {
        Thread t = new Thread(new Runnable() {
            @Override
            public void run() {
                Socket socket = null;
                DataOutputStream out = null;
                FileInputStream inputStream = null;
                try {
                    socket = new Socket(printerIP, printerPort);
                    out = new DataOutputStream(socket.getOutputStream());
                    DataInputStream input = new DataInputStream(socket.getInputStream());
                    inputStream = new FileInputStream(file);
                    byte[] buffer = new byte[3000];

                    final char ESC = 0x1b;
                    final String UEL = ESC + "%-12345X";
                    final String ESC_SEQ = ESC + "%-12345\r\n";

                    out.writeBytes(UEL);
                    out.writeBytes("@PJL \r\n");
                    out.writeBytes("@PJL JOB NAME = '" + filename + "' \r\n");
                    out.writeBytes("@PJL SET PAPER=" + paperSize.name());
                    out.writeBytes("@PJL SET COPIES=" + copies);
                    out.writeBytes("@PJL ENTER LANGUAGE = PDF\r\n");
                    while (inputStream.read(buffer) != -1)
                        out.write(buffer);
                    out.writeBytes(ESC_SEQ);
                    out.writeBytes("@PJL \r\n");
                    out.writeBytes("@PJL RESET \r\n");
                    out.writeBytes("@PJL EOJ NAME = '" + filename + "'");
                    out.writeBytes(UEL);

                    out.flush();
                } catch (IOException e) {
                    e.printStackTrace();
                    if (printListener != null)
                        printListener.networkError();
                } finally {
                    try {
                        if (inputStream != null)
                            inputStream.close();
                        if (out != null)
                            out.close();
                        if (socket != null)
                            socket.close();
                        if (printListener != null)
                            printListener.printCompleted();
                    } catch (IOException e) {
                        e.printStackTrace();
                        if (printListener != null)
                            printListener.networkError();
                    }
                }
            }
        });
        t.start();
    }

    public static void setPrintListener(PrintListener list) {
        printListener = list;
    }

    public interface PrintListener {
        void printCompleted();

        void networkError();
    }
}

【讨论】：

假设它接受 PJL 并且知道如何在打印机中本地打印 PDF。我从事打印机固件工作已有十多年了，但在当时，第二个固件将是一个巨大的假设。
谢谢，这似乎是一个很好的解决方案。但我发现错误：java.net.SocketException: sendto failed: ECONNRESET (Connection reset by peer) 我更新了我的问题，添加了错误图片
您要发送到哪个端口？如果我没记错的话，PJL 通常在 9100 上工作。
@Cristian 我试过 631 端口。我以为所有打印机都连接到 631 端口。好的，我试试9100。
谢谢@Cristian，您的解决方案有效，但使用其他打印机。我的第一台打印机不支持 PDF 和 PostScript

【解决方案2】：

@Cristian 用 AsyncTask 实现回答。通过此实现，您可以针对 PrintServiceListener 回调执行 UI 操作。

public class CustomPrinterService extends AsyncTask<Void, Void, Boolean> {

public enum PaperSize {
    A4,
    A5
}

private static final String TAG = "CustomPrinterService";

private PrintServiceListener mPrintServiceListener;

private String mPrinterIP;
private String mFilename;

private int mPrinterPort;
private int mNumberOfCopies;

private File mFile;
private PaperSize mPaperSize;

public CustomPrinterService(final String printerIP, final int printerPort, final File file,
                            final String filename, final PaperSize paperSize, final int copies) {
    mPrinterIP = printerIP;
    mPrinterPort = printerPort;
    mFile = file;
    mFilename = filename;
    mPaperSize = paperSize;
    mNumberOfCopies = copies;
}

@Override
protected Boolean doInBackground(Void... voids) {
    Boolean result = null;
    Socket socket = null;
    DataOutputStream out = null;
    FileInputStream inputStream = null;
    try {
        socket = new Socket(mPrinterIP, mPrinterPort);
        out = new DataOutputStream(socket.getOutputStream());
        DataInputStream input = new DataInputStream(socket.getInputStream());
        inputStream = new FileInputStream(mFile);
        byte[] buffer = new byte[3000];

        final char ESC = 0x1b;
        final String UEL = ESC + "%-12345X";
        final String ESC_SEQ = ESC + "%-12345\r\n";

        out.writeBytes(UEL);
        out.writeBytes("@PJL \r\n");
        out.writeBytes("@PJL JOB NAME = '" + mFilename + "' \r\n");
        out.writeBytes("@PJL SET PAPER=" + mPaperSize.name());
        out.writeBytes("@PJL SET COPIES=" + mNumberOfCopies);
        out.writeBytes("@PJL ENTER LANGUAGE = PDF\r\n");
        while (inputStream.read(buffer) != -1)
            out.write(buffer);
        out.writeBytes(ESC_SEQ);
        out.writeBytes("@PJL \r\n");
        out.writeBytes("@PJL RESET \r\n");
        out.writeBytes("@PJL EOJ NAME = '" + mFilename + "'");
        out.writeBytes(UEL);

        out.flush();
    } catch (Exception exception) {
        Log.d(TAG, exception.toString());
        result = false;
    } finally {
        try {
            if (inputStream != null) {
                inputStream.close();
            }
            if (out != null) {
                out.close();
            }
            if (socket != null) {
                socket.close();
            }
            if (result == null) {
                result = true;
            }
        } catch (Exception exception) {
            Log.d(TAG, exception.toString());
            result = false;
        }
    }
    return result;
}

@Override
protected void onPostExecute(Boolean result) {
    super.onPostExecute(result);
    if (result) {
        if (mPrintServiceListener != null) {
            mPrintServiceListener.onPrintCompleted();
        }
    } else {
        if (mPrintServiceListener != null) {
            mPrintServiceListener.onNetworkError();
        }
    }
}

public void setPrintServiceListener(PrintServiceListener listener) {
    mPrintServiceListener = listener;
}

public interface PrintServiceListener {

    void onPrintCompleted();

    void onNetworkError();
}

}

【讨论】：

【解决方案3】：

除了 Gokula 的回答：

也可以在设备上不保存文件的情况下执行此操作。就我而言，我使用字节数组或 base 64 来打印图像。
kotlin 中的代码 =)

打印机控制器调用

override fun write(content: String, address: String?) {
    address?.let {
        val policy: StrictMode.ThreadPolicy = StrictMode.ThreadPolicy.Builder().permitAll().build()
        StrictMode.setThreadPolicy(policy)
        Base64.decode("Base64 image content goes here", Base64.DEFAULT).printByDeviceIp(address)
    }
}

打印机扩展

fun ByteArray.printByDeviceIp(address: String) {
    try {
        val socket = Socket(address, PRINTER_DEFAULT_PORT)
        val output = DataOutputStream(socket.getOutputStream())
        val buffer = ByteArray(PRINTER_BUFFER_SIZE)
        val inputStream = ByteArrayInputStream(this)

        output.writeBytes(UEL)
        output.writeBytes(PRINT_META_JOB_START)
        output.writeBytes(PRINT_META_JOB_NAME)
        output.writeBytes(PRINT_META_JOB_PAPER_TYPE)
        output.writeBytes(PRINT_META_JOB_COPIES)
        output.writeBytes(PRINT_META_JOB_LANGUAGE)

        while (inputStream.read(buffer) != -1)
            output.write(buffer)

        output.writeBytes(ESC_SEQ)
        output.writeBytes(UEL)

        output.flush()

        inputStream.close()
        output.close()
        socket.close()
    } catch (e: Exception) {
        when(e) {
        is SocketException -> Log.e(this.javaClass.name, "Network failure: ${e.message}")
        is SocketTimeoutException -> Log.e(this.javaClass.name, "Timeout: ${e.message}")
        is IOException -> Log.e(this.javaClass.name, "Buffer failure: ${e.message}")
        else -> Log.e(this.javaClass.name, "General failure: ${e.message}")
    }
}

打印机作业常量

private const val PRINT_META_JOB_LABEL = "@PJL"
private const val PRINT_META_BREAK = "\r\n"

private const val ESCAPE_KEY = 0x1b.toChar()
const val UEL = "$ESCAPE_KEY%-12345X"
const val ESC_SEQ = "$ESCAPE_KEY%-12345 $PRINT_META_BREAK"

const val PRINT_META_JOB_START = "$PRINT_META_JOB_LABEL $PRINT_META_BREAK"
const val PRINT_META_JOB_NAME = "$PRINT_META_JOB_LABEL JOB NAME = 'INBOUND_FINISH' $PRINT_META_BREAK"
const val PRINT_META_JOB_PAPER_TYPE = "$PRINT_META_JOB_LABEL SET PAPER = A4"
const val PRINT_META_JOB_COPIES = "$PRINT_META_JOB_LABEL SET COPIES = 1"
const val PRINT_META_JOB_LANGUAGE = "$PRINT_META_JOB_LABEL ENTER LANGUAGE = PDF $PRINT_META_BREAK"

const val PRINTER_DEFAULT_PORT: Int = 9100
const val PRINTER_BUFFER_SIZE: Int = 3000

【讨论】：