最近公司的餐厅点餐app又提了新需求,增加对usb打印机的支持。
USB开发,涉及到主从模式
主机模式
Android设备充当主主设备，并为总线供电。
例如数字相机，键盘，鼠标和游戏控制器。USB设备与Android应用进行数据交互。附件模式(从属)
外部硬件充当USB主设备，并为总线供电。例如手机和电脑连接
主从模式图
做usb通信，首先要先弄清楚哪边是HOST那边是SLAVE。
比如你的android手机做host，要获得slave，用UsbDevice表示slave
要是你的android手机做slave，要获得host，用UsbAccessory表示host
我们的项目是主模式开发,也就是说USB打印机连接到我们的点餐设备上,点餐设备充当USB主设备,并为总线供电。
首先你可以在manifest.xml清单文件中,声明usb权限是否为必须。
如果不声明，默认为false。
如果required=true,则在安装app的同时,如果android设备不支持usb功能,则app是无法安装的。
同时，做声明的好处是，如果你的app受众人群在国外，那么googleplay会帮你过滤掉没有usb功能的设备，也就是说没有usb功能的设备时搜索不到或者无法下载你的app的!
声明插入或拔出usb设备时,打开指定的activity.
声明要过滤的usb设备的相关信息
vender-id为生产厂家号 product-id为产品号
其中vendor-id和product-id为插入USB设备的生产厂家号和产品号，在 插入（attached）上面列出的设备之一时，就会弹出选择打开应用程序的对话框。
usb开发的相关api在android.hardware.usb包下
image.png
| 类 | 说明 |
|---|---|
| UsbManager | 获得 USB 管理器，与连接的 USB 设备通信。 |
| UsbDevice | host模式下,USB 设备的抽象，每个UsbDevice 都代表一个 USB 设备。 |
| UsbAccessory | (从属模式下,也就是你的android设备相当于一个附件挂在usb设备上)此时的UsbAccessory代表的就是android设备所挂在的那个设备 |
| UsbInterface | 表示一个UsbDevice的一个接口。UsbDevice可以具有一个或多个在接口用来通信。 |
| UsbEndpoint | 表示一个UsbInterface一个端点，它是接口的通信通道。一个接口可以具有一个或多个端点，与设备进行双向通信通常有一个端点用于输入和一个端点用于输出。 |
| UsbDeviceConnection | 表示与设备的连接，用来收发数据，传输控制信息。 |
| UsbRequest | 通过UsbDeviceConnection与设备通信的异步请求，只用来异步通信 |
| UsbConstants | USB常量定义,与Linux内核的linux / usb / ch9.h中的定义相对应 |
UsbPort
package com.mjt.factory.print.engine;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.hardware.usb.UsbConstants;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbEndpoint;
import android.hardware.usb.UsbInterface;
import android.hardware.usb.UsbManager;
import android.util.Log;
import com.gprinter.io.PortManager;
import com.gprinter.utils.Utils;
import com.mjt.common.base.CommonLib;
import java.io.IOException;
import java.util.Vector;
import static com.mjt.common.constants.Constants.ACTION_USB_PERMISSION;
/**
* Copyright:mjt_pad_android
* Author: liyang
* Date:2019-05-28 14:07
* Desc:
*/
public class UsbPort extends PortManager {
private static final String TAG = UsbPort.class.getSimpleName();
private UsbDevice usbDevice;
private UsbManager usbManager;
private UsbDeviceConnection connection;
private UsbInterface interf;
private UsbEndpoint epIn, epOut;
public static final int USB_REQUEST_CODE = 0;
public UsbPort(UsbDevice device) {
usbDevice = device;
usbManager = (UsbManager) CommonLib.getContext().getSystemService(Context.USB_SERVICE);
}
public boolean openPort() {
if (this.usbDevice != null) {
if (!this.usbManager.hasPermission(this.usbDevice)) {
PendingIntent intent = PendingIntent.getBroadcast(CommonLib.getContext(), USB_REQUEST_CODE, new Intent(ACTION_USB_PERMISSION), 0);
usbManager.requestPermission(usbDevice, intent);
return false;
} else {
openUsbPort();
return epOut != null;
}
}
return false;
}
private void openUsbPort() {
int count = usbDevice.getInterfaceCount();
UsbInterface usbInterface = null;
if (count > 0) {
usbInterface = usbDevice.getInterface(0);
}
if (usbInterface != null) {
interf = usbInterface;
connection = null;
connection = usbManager.openDevice(usbDevice);
}
if (connection != null && connection.claimInterface(interf, true)) {
for (int i = 0; i < interf.getEndpointCount(); ++i) {
UsbEndpoint ep = interf.getEndpoint(i);
if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
if (ep.getDirection() == UsbConstants.USB_DIR_OUT) {
this.epOut = ep;
} else {
this.epIn = ep;
}
}
}
}
}
public void writeDataImmediately(Vector data) throws IOException {
this.writeDataImmediately(data, 0, data.size());
}
public void writeDataImmediately(Vector data, int offset, int len) throws IOException {
int result = 0;
Vector sendData = new Vector<>();
for (int i = 0; i < data.size(); ++i) {
if (sendData.size() >= 1024) {
Log.e(TAG, "i = " + i + "\tsendData size -> " + sendData.size() + "\tdata size -> " + data.size());
result += this.connection.bulkTransfer(this.epOut, Utils.convertVectorByteTobytes(sendData), sendData.size(), 1000);
sendData.clear();
Log.e(TAG, "sendData.clear() size -> " + sendData.size());
}
sendData.add(data.get(i));
}
if (sendData.size() > 0) {
Log.e(TAG, "sendData size -> " + sendData.size());
result += this.connection.bulkTransfer(this.epOut, Utils.convertVectorByteTobytes(sendData), sendData.size(), 1000);
}
if (result == data.size()) {
Log.d(TAG, "send success");
}else {
throw new IOException("send failed");
}
}
public int readData(byte[] bytes) throws IOException {
return this.connection != null&&epIn!=null ? this.connection.bulkTransfer(this.epIn, bytes, bytes.length, 200) : 0;
}
public boolean closePort() {
if (this.interf != null && this.connection != null) {
this.connection.releaseInterface(this.interf);
this.connection.close();
this.connection = null;
return true;
} else {
return false;
}
}
public UsbDevice getUsbDevice() {
return this.usbDevice;
}
public void setUsbDevice(UsbDevice usbDevice) {
this.usbDevice = usbDevice;
}
}
在MainActivity中注册Usb广播
private final BroadcastReceiver usbDeviceReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
Log.d("action", action);
UsbDevice mUsbDevice = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (ACTION_USB_PERMISSION.equals(action)) {
synchronized (this) {
if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false) && mUsbDevice != null) {
Log.d("receiver", action + ",device:" + mUsbDevice.getDeviceName() + "被授予了权限!");
} else {
UIUtils.showToast(context, "USB设备请求被拒绝");
}
}
} else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
if (mUsbDevice != null) {
UIUtils.showToast(context, "有设备拔出");
EventBus.getDefault().post(new UsbAttachedChangedEvent(mUsbDevice, false));
}
} else if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
if (mUsbDevice != null) {
UIUtils.showToast(context, "有设备插入");
EventBus.getDefault().post(new UsbAttachedChangedEvent(mUsbDevice, true));
}
}
}
};
DeviceConnManager类的openPort方法
/**
* 打开端口
*
* @return
*/
public void openPort(boolean needNotify) {
this.needNotify = needNotify;
isOpenPort = false;
sendStateBroadcast(CONN_STATE_CONNECTING);
switch (connMethod) {
case BLUETOOTH:
System.out.println("id -> " + id);
mPort = new BluetoothPort(macAddress);
isOpenPort = mPort.openPort();
break;
case USB:
mPort = new UsbPort(mUsbDevice);
isOpenPort = mPort.openPort();
break;
case WIFI:
mPort = new EthernetPort(ip, port);
isOpenPort = mPort.openPort();
break;
case SERIAL_PORT:
mPort = new SerialPort(serialPortPath, baudrate, 0);
isOpenPort = mPort.openPort();
break;
default:
break;
}
//端口打开成功后，检查连接打印机所使用的打印机指令ESC、TSC
Log.e(TAG, "openPort :" + isOpenPort + ",thread is " + Thread.currentThread().getName());
if (!isOpenPort) {
if (getConnMethod() == CONN_METHOD.USB && mUsbDevice != null) {
mUsbDevice = null;
}
mPort.closePort();
sendStateBroadcast(CONN_STATE_FAILED);
} else {
sendStateBroadcast(CONN_STATE_CONNECTED);
}
}
PrinterManager类中的addUsbPrinter方法和connectUsb方法
public void addUsbPrinter(String id, String name) {
DeviceConnFactoryManager usbManager = getManager(id);
UsbManager manager = (UsbManager) CommonLib.getContext().getSystemService(Context.USB_SERVICE);
UsbDevice usbDevice = null;
for (UsbDevice usb : manager.getDeviceList().values()) {
String pidVid = String.format("%s%s", usb.getProductId(), usb.getVendorId());
if (usb.getInterface(0).getInterfaceClass() == UsbConstants.USB_CLASS_PRINTER && pidVid.equals(id)) {
usbDevice = usb;
}
}
if (usbManager == null) {
if (usbDevice != null) {
new DeviceConnFactoryManager.Build().setId(id)
.setConnMethod(DeviceConnFactoryManager.CONN_METHOD.USB)
.setName(name)
.setUsbDevice(usbDevice)
.build();
}
} else {
//由于usb设备每次查吧usbdevice的deviceId都会变,所以需要重新设备UsbDevice
if (usbDevice != null && usbManager.usbDevice() == null) {
usbManager.setUsbDevice(usbDevice);
}
}
}
public void connectUsb(String pidVid, String name, boolean needNotify) {
DeviceConnFactoryManager deviceManager = getManager(pidVid);
UsbManager manager = (UsbManager) CommonLib.getContext().getSystemService(Context.USB_SERVICE);
UsbDevice usbDevice = null;
for (UsbDevice usb : manager.getDeviceList().values()) {
String pv = String.format("%s%s", usb.getProductId(), usb.getVendorId());
if (usb.getInterface(0).getInterfaceClass() == UsbConstants.USB_CLASS_PRINTER && pidVid.equals(pv)) {
usbDevice = usb;
}
}
if (deviceManager == null) {
if (usbDevice != null) {
new DeviceConnFactoryManager.Build().setId(pidVid)
.setConnMethod(DeviceConnFactoryManager.CONN_METHOD.USB)
.setUsbDevice(usbDevice)
.setName(name)
.build();
} else {
Log.e(TAG, "connectUsb: usbDevice is null");
}
} else {
if (usbDevice != null) {
deviceManager.setUsbDevice(usbDevice);
} else {
Log.e(TAG, "connectUsb: usbDevice is null");
}
}
if (getManager(pidVid)!=null){
getManager(pidVid).openPort(needNotify);
}else {
UIUtils.showToast("请确保已插入该USB打印机!");
Log.e(TAG, String.format("connectUsb: getManager(%s)",pidVid));
}
}