第一：请求权限和请求权限回调(通过广播回调)

注册一个广播接收器用于接收USB权限被同意或拒绝后发出的广播

//注册USB设备权限管理广播

IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION); //ACTION_USB_PERMISSION为自定义的字符串

context.registerReceiver(usbReceiver, filter);

其中usbReceiver的实现是：

private BroadcastReceiver usbReceiver = new BroadcastReceiver() {

@Override

public void onReceive(Context context, Intent intent) {

final String action = intent.getAction();

if(action.equals(ACTION_USB_PERMISSION)){//ACTION_USB_PERMISSION是前面我们自己自定义的字符串

UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);

if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {

if (device != null) {

LogUtils.i("已获取USB权限");

}

} else {

LogUtils.i("USB权限被拒绝");

}

};

请求权限：

PendingIntent mPermissionIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);//关于这个mPermissionIntent ，具体的作用我还没弄明白，明白以后补充

manager = (UsbManager) context.getSystemService(Context.USB_SERVICE);

manager.requestPermission(device,mPermissionIntent);//device是具体某个usb设备

执行完这个后，界面会弹出对话框询问用户是否授予权限，然后会发送权限广播，所以上面我们注册一个广播接收器来判断权限状态

第二：注册USB设备插拔广播

USB设备被插/拔后同样会发送一个广播，因此我们需要注册一个接收器来接收这个广播

IntentFilter stateFilter = new IntentFilter();

stateFilter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);

stateFilter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);

context.registerReceiver(usbStateReceiver, stateFilter);

其中.usbStateReceiver的实现如下：

private BroadcastReceiver usbStateReceiver = new BroadcastReceiver() {

@Override

public void onReceive(Context context, Intent intent) {

String action = intent.getAction();

//USB连接上手机时会发送广播android.hardware.usb.action.USB_STATE"及UsbManager.ACTION_USB_DEVICE_ATTACHED

if (action.equals(UsbManager.ACTION_USB_DEVICE_ATTACHED)) {

LogUtils.i("有USB设备连接");

} else if (action.equals(UsbManager.ACTION_USB_DEVICE_DETACHED)) {//USB被拔出

LogUtils.i("USB连接断开，程序退出！");

}

}

};

详细介绍以上两种，另附一个自己写的USBUtil，里面的思路是，初始化话时传入要连接设备的VendorId和ProductId，然后自动进行搜索，连接，授权等。只暴露读/写，开/关给外界，其他的全部自己处理

未经测试，请勿直接使用，仅供参考！！！！

package com.police.policefaceproject.utils;

import android.app.Activity;

import android.app.PendingIntent;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.DialogInterface;

import android.content.Intent;

import android.content.IntentFilter;

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 java.util.Iterator;

import java.util.Map;

/**

* Created by Administrator on 2018/4/18.

*/

public class USBUtils {

private Activity activity;

private final String ACTION_USB_PERMISSION = "com.gudi.usb.permission";

private UsbManager manager;

private PendingIntent mPermissionIntent;

private BroadcastReceiver usbReceiver = new BroadcastReceiver() {

@Override

public void onReceive(Context context, Intent intent) {

final String action = intent.getAction();

if(action.equals(ACTION_USB_PERMISSION)){

UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);

if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {

if (device != null) {

USBCtrl(context);

}

} else {

LogUtils.i("USB权限被拒绝");

if(activity!=null && !activity.isDestroyed()){

activity.runOnUiThread(new Runnable() {

@Override

public void run() {

UiUtils.Alert(activity, "权限错误", "请重新插拔设备后，授予应用访问USB权限","确定", new UiUtils.AlertCallBackOne() {

@Override

public void onClick(DialogInterface dialogInterface, int i) {

}

});

;

}

});

}

}

}

}

};

private UsbDeviceConnection usbConnection;

private UsbEndpoint uepIn;

private UsbEndpoint uepOut;

private int mProductId,mVendorId;

private BroadcastReceiver usbStateReceiver = new BroadcastReceiver() {

@Override

public void onReceive(Context context, Intent intent) {

String action = intent.getAction();

//USB连接上手机时会发送广播android.hardware.usb.action.USB_STATE"及UsbManager.ACTION_USB_DEVICE_ATTACHED

if (action.equals(UsbManager.ACTION_USB_DEVICE_ATTACHED)) {//判断其中一个就可以了

LogUtils.i("有USB设备连接");

showMsg("有USB设备连接");

USBCtrl(context);

} else if (action.equals(UsbManager.ACTION_USB_DEVICE_DETACHED)) {//USB被拔出

LogUtils.i("USB连接断开，程序退出！");

showMsg("USB连接断开，请重试");

closeConn();

}

}

};

public void init(Activity context,int productId,int vendorId){

activity = context;

mProductId = productId;

mVendorId = vendorId;

manager = (UsbManager) context.getSystemService(Context.USB_SERVICE);

mPermissionIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);

//注册USB设备权限管理广播

IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);

context.registerReceiver(usbReceiver, filter);

//注册USB设备插拔广播

IntentFilter stateFilter = new IntentFilter();

stateFilter.addAction(UsbManager.ACTION_USB_ACCESSORY_ATTACHED);

stateFilter.addAction(UsbManager.ACTION_USB_DEVICE_ATTACHED);

stateFilter.addAction(UsbManager.ACTION_USB_DEVICE_DETACHED);

context.registerReceiver(usbStateReceiver, stateFilter);

}

private Map getDevices(){

if(manager != null){

Map deviceMap = manager.getDeviceList();

return deviceMap;

}

return null;

}

private UsbDeviceConnection openDevice(Context context,UsbDevice device){

if(manager.hasPermission(device)){

UsbDeviceConnection DeviceConnection = manager.openDevice(device);

return DeviceConnection;

}else{

LogUtils.i("请求USB权限");

manager.requestPermission(device,mPermissionIntent);

return null;

}

}

private void USBCtrl(Context context){

//获取设备列表

Map devicesList= getDevices();

if(devicesList == null || devicesList.size() <=0){

LogUtils.e("未查找到USB设备");

showMsg("未查找到设备，请重新插拔设备");

}else{

//遍历寻找指定设备

Iterator deviceIterator = devicesList.values().iterator();

while(deviceIterator.hasNext()){

UsbDevice usb= deviceIterator.next();

if(usb.getVendorId() == mVendorId && usb.getProductId() == mProductId){

//查找到指定设备

connDevice(context,usb);

break;

}

}

}

}

private void connDevice(Context context,UsbDevice device){

UsbEndpoint uep;

//获得设备接口

UsbInterface usbInterface = device.getInterface(0);

//查找输入，输出端

for(int i =0;i

uep=usbInterface.getEndpoint(i);

if(uep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK){

if(uep.getDirection() == UsbConstants.USB_DIR_IN){

uepIn = uep;

}else if(uep.getDirection() == UsbConstants.USB_DIR_OUT){

uepOut = uep;

}

}

}

usbConnection = openDevice(context,device);

if(usbConnection == null){

LogUtils.e("连接设备失败");

showMsg("连接设备失败，请赋予权限");

return ;

}

if(usbConnection.claimInterface(usbInterface,true)){//声明独占此接口，在发送或接收数据前完成

//锁定成功

}else{

//锁定失败

usbConnection.close();

usbConnection = null;

LogUtils.e("锁定接口失败");

showMsg("锁定接口失败，请插拔设备重试");

}

}

public int write(byte[] data){

if(usbConnection != null){

int len= usbConnection.bulkTransfer(uepOut, data, data.length, 3000);

LogUtils.i("通过USB接口发送"+data.length+"数据");

return len;

}else{

LogUtils.i("usbConnection为null");

return -1;

}

}

public byte[] read(byte[] data){

if(usbConnection != null){

int len= usbConnection.bulkTransfer(uepOut, data, data.length, 3000);

LogUtils.i("通过USB接口接收"+data.length+"数据");

return data;

}else{

LogUtils.i("接收数据，usbConnection为null");

return null;

}

}

public void closeConn(){

if(usbConnection != null){

usbConnection.close();

usbConnection=null;

}

}

private void showMsg(final String msg){

if(activity!=null ){

activity.runOnUiThread(new Runnable() {

@Override

public void run() {

UiUtils.toast(activity.getApplicationContext(),msg);

}

});

}

}

}

未经测试，请勿直接使用，仅供参考！！！！