Question

我目前正在创建一个Android应用程序，需要能够从移动打印机打印票据/收据。我目前所在的组织决定购买目前运行7.0的安卓平板电脑以及Zebra移动打印机（ZQ510）。我们确定使用BluetoothConnectionInsecure是连接和打印这些打印机的最佳方法，因为该应用程序将用于连接到自己的打印机的多个平板电脑上。

虽然我们能够成功连接并打印以前版本的应用程序，该应用程序旨在与运行5.0及更高版本的Android设备一起使用，但似乎我们的应用程序的当前版本无法与打印机建立连接。

我已经通过堆栈查找了类似的错误，但无法找到任何错误。如果有一个类似于我的，我会很感激链接。

Zebra printer connection failed “read failed, socket might closed or timeout, read ret: -1”

以下是错误的堆栈跟踪： 01-18 14:24:08.332 9048-9165/marist.edu.mets_issue_ticket W/System.err: com.zebra.sdk.comm.ConnectionException: Could not connect to device: read failed, socket might closed or timeout, read ret: -1 01-18 14:24:08.333 9048-9165/marist.edu.mets_issue_ticket W/System.err: at com.zebra.sdk.comm.ConnectionA.open(Unknown Source) 01-18 14:24:08.333 9048-9165/marist.edu.mets_issue_ticket W/System.err: at com.zebra.sdk.comm.BluetoothConnection.open(Unknown Source) 01-18 14:24:08.333 9048-9165/marist.edu.mets_issue_ticket W/System.err: at marist.edu.mets_issue_ticket_helpers.BluetoothUnsecurePrint$1.run(BluetoothUnsecurePrint.java:308) 01-18 14:24:08.333 9048-9165/marist.edu.mets_issue_ticket W/System.err: at java.lang.Thread.run(Thread.java:761) 01-18 14:24:08.333 9048-9165/marist.edu.mets_issue_ticket W/System.err: Caused by: com.zebra.sdk.comm.ConnectionException: read failed, socket might closed or timeout, read ret: -1 01-18 14:24:08.333 9048-9165/marist.edu.mets_issue_ticket W/System.err: at com.zebra.sdk.comm.internal.BluetoothInsecureZebraConnectorImpl.tryPublicApiWay(Unknown Source) 01-18 14:24:08.333 9048-9165/marist.edu.mets_issue_ticket W/System.err: at com.zebra.sdk.comm.internal.BluetoothInsecureZebraConnectorImpl.open(Unknown Source)

我目前用于与打印机建立连接的方法如下：

创建搜索可发现设备的意图，然后将该意图传递给我的蓝牙类：

Intent discoverableIntent =
                new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
        discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);

        BluetoothUnsecurePrint bluetoothUnsecurePrint = new BluetoothUnsecurePrint(resultMap,violationResults,getActivity(), theTicketNumber, discoverableIntent);
        bluetoothUnsecurePrint.print();

收集找到的设备列表，并获取已与平板电脑配对的设备的MAC地址：

    public void print(){
    //ask user to allow device to be discoverable by paired printer, display dialog box
 discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
    userActivity.startActivity(discoverableIntent);
    bluetoothAdapter = BluetoothAdapter.getDefaultAdapter().getAddress();

    BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    if (mBluetoothAdapter == null) {
        // Device does not support Bluetooth
    }

    Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();

    if (pairedDevices.size() > 0) {
        // There are paired devices. Get the name and address of each paired device.
        for (BluetoothDevice device : pairedDevices) {
            String deviceHardwareAddress = device.getAddress(); // MAC address
            sendZplOverBluetooth(deviceHardwareAddress);

            Log.d(TAG,device.getAddress()+ device.getName()+device.getBondState());

            Intent ticketFinishedIntent = new Intent(userActivity, OffendingVehicleSearch.class);
            userActivity.startActivity(ticketFinishedIntent);
        }
    }
}

使用蓝牙mac地址建立与打印机的连接，然后打印已写入的数据。

private void sendZplOverBluetooth(final String theBtMacAddress) {

    new Thread(new Runnable() {
        public void run() {
            try {
                // Instantiate insecure connection for given Bluetooth&reg; MAC Address.
                Connection thePrinterConn = new BluetoothConnectionInsecure(theBtMacAddress);

                // Initialize
                Looper.prepare();
                Log.d(TAG,thePrinterConn.getSimpleConnectionName());

                // Open the connection - physical connection is established here.
                thePrinterConn.open();
                Log.d(TAG, String.valueOf(thePrinterConn.bytesAvailable()));
                // Send the data to printer as a byte array.
                thePrinterConn.write(generateZPL().getBytes());

                // Make sure the data got to the printer before closing the connection
                Thread.sleep(500);

                // Close the insecure connection to release resources.
                thePrinterConn.close();

                Looper.myLooper().quit();
            } catch (Exception e) {
                // Handle communications error here.
                e.printStackTrace();
            }
        }
    }).start();
}

我确实遇到过一些其他与半相关的论坛帖子，这些帖子涉及清单文件所需的可能新权限，但看起来这些权限不会对连接错误产生影响。

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-permission android:name="android.permission.CAMERA" />

<uses-feature android:name="android.hardware.camera2.full" />

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

如果需要任何其他信息，请与我们联系。

无法打开与Zebra打印机的连接

0 个答案: