嘿，我是 android 开发新手，并且在 android 中获得了一些初学者知识，现在我正在做一个通过 USB 与热敏打印机连接的应用程序，实际上我正在打印一个文本文件，其中包含一些堆栈溢出中的引用，但我需要打印条形码输入。我正在尝试打印一维条码，但我没有成功。任何人都可以为我的问题提供一些建议或解决方案。
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
mDeviceList = mUsbManager.getDeviceList();
mDeviceIterator = mDeviceList.values().iterator();
Button print = (Button) findViewById(R.id.print);
final Button printBarcode = findViewById(R.id.barcode);
Toast.makeText(this, "Device List Size: " + String.valueOf(mDeviceList.size()), Toast.LENGTH_SHORT).show();
TextView textView = (TextView) findViewById(R.id.usbDevice);
String usbDevice = "";
//This is just testing what devices are connected
while (mDeviceIterator.hasNext()) {
UsbDevice usbDevice1 = mDeviceIterator.next();
usbDevice += "\n" +
"DeviceID: " + usbDevice1.getDeviceId() + "\n" +
"DeviceName: " + usbDevice1.getDeviceName() + "\n" +
"DeviceClass: " + usbDevice1.getDeviceClass() + " - " + translateDeviceClass(usbDevice1.getDeviceClass()) + "\n" +
"DeviceSubClass: " + usbDevice1.getDeviceSubclass() + "\n" +
"VendorID: " + usbDevice1.getVendorId() + "\n" +
"ProductID: " + usbDevice1.getProductId() + "\n";
int interfaceCount = usbDevice1.getInterfaceCount();
Toast.makeText(this, "INTERFACE COUNT: " + String.valueOf(interfaceCount), Toast.LENGTH_SHORT).show();
mDevice = usbDevice1;
if (mDevice == null) {
Toast.makeText(this, "mDevice is null", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "mDevice is not null", Toast.LENGTH_SHORT).show();
}
textView.setText(usbDevice);
}
if (mDevice == null) {
Toast.makeText(this, "mDevice is null", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "mDevice is not null", Toast.LENGTH_SHORT).show();
}
mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
registerReceiver(mUsbReceiver, filter);
mUsbManager.requestPermission(mDevice, mPermissionIntent);
print.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
print(mConnection, mInterface);
}
});
printBarcode.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
printBarcode(mConnection,mInterface);
}
});
}
private String translateDeviceClass(int deviceClass) {
switch (deviceClass) {
case UsbConstants.USB_CLASS_APP_SPEC:
return "Application specific USB class";
case UsbConstants.USB_CLASS_AUDIO:
return "USB class for audio devices";
case UsbConstants.USB_CLASS_CDC_DATA:
return "USB class for CDC devices (communications device class)";
case UsbConstants.USB_CLASS_COMM:
return "USB class for communication devices";
case UsbConstants.USB_CLASS_CONTENT_SEC:
return "USB class for content security devices";
case UsbConstants.USB_CLASS_CSCID:
return "USB class for content smart card devices";
case UsbConstants.USB_CLASS_HID:
return "USB class for human interface devices (for example, mice and keyboards)";
case UsbConstants.USB_CLASS_HUB:
return "USB class for USB hubs";
case UsbConstants.USB_CLASS_MASS_STORAGE:
return "USB class for mass storage devices";
case UsbConstants.USB_CLASS_MISC:
return "USB class for wireless miscellaneous devices";
case UsbConstants.USB_CLASS_PER_INTERFACE:
return "USB class indicating that the class is determined on a per-interface basis";
case UsbConstants.USB_CLASS_PHYSICA:
return "USB class for physical devices";
case UsbConstants.USB_CLASS_PRINTER:
return "USB class for printers";
case UsbConstants.USB_CLASS_STILL_IMAGE:
return "USB class for still image devices (digital cameras)";
case UsbConstants.USB_CLASS_VENDOR_SPEC:
return "Vendor specific USB class";
case UsbConstants.USB_CLASS_VIDEO:
return "USB class for video devices";
case UsbConstants.USB_CLASS_WIRELESS_CONTROLLER:
return "USB class for wireless controller devices";
default:
return "Unknown USB class!";
}
}
Broadcast receiver to obtain permission from user for connection
final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (ACTION_USB_PERMISSION.equals(action)) {
synchronized (this) {
UsbDevice device = (UsbDevice)
intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED,
false)) {
if (device != null) {
//call method to set up device communication
mInterface = device.getInterface(0);
mEndPoint = mInterface.getEndpoint(0);
mConnection = mUsbManager.openDevice(device);
//setup();
}
} else {
//Log.d("SUB", "permission denied for device " + device);
Toast.makeText(context, "PERMISSION DENIED FOR THIS DEVICE", Toast.LENGTH_SHORT).show();
}
}
}
}
};
打印文本文件
private void print(UsbDeviceConnection connection, UsbInterface intrface) {
String test = "Together Forever";
byte[] testBytes = test.getBytes(Charset.forName("UTF-8"));
if (intrface == null) {
Toast.makeText(this, "INTERFACE IS NULL", Toast.LENGTH_SHORT).show();
}
if (connection == null) {
Toast.makeText(this, "CONNECTION IS NULL", Toast.LENGTH_SHORT).show();
}
if (forceCLaim == null) {
Toast.makeText(this, "FORCE CLAIM IS NULL", Toast.LENGTH_SHORT).show();
}
connection.claimInterface(intrface, forceCLaim);
connection.bulkTransfer(mEndPoint, testBytes, testBytes.length, 0);
打印条码
private void printBarcode(UsbDeviceConnection connection, UsbInterface intrface){
String content = "115";
//1D barcode format (hex): 1d 6b 02 0d + barcode data
byte[] formats = {(byte) 0x1d, (byte) 0x6b, (byte) 0x02, (byte) 0x0d};
byte[] contents = content.getBytes();
byte[] bytes = new byte[formats.length + contents.length];
System.arraycopy(formats, 0, bytes, 0, formats.length);
System.arraycopy(contents, 0, bytes, formats.length, contents.length);
connection.claimInterface(intrface, forceCLaim);
connection.bulkTransfer(mEndPoint, bytes, bytes.length, 0);
在谷歌搜索很多解决方案，但我没有得到任何合适的解决方案。