Develop Reference

Android smart-card interface over USB

I need to read/write to a smart-card using a smart-card reader attached to an Android phone by USB.
Is this possible with native APIs or do I have to install other libraries?
Thank you

In java the communication takes place using package javax.smarcard which is not available for Android so take a look here for getting an idea as to how you can communicate or send/receive APDU (smartcard command).
Using the USB Host API to connect :
:
//Allows you to enumerate and communicate with connected USB devices.
UsbManager mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
//Explicitly asking for permission
final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
PendingIntent mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
HashMap<String, UsbDevice> deviceList = mUsbManager.getDeviceList();
UsbDevice device = deviceList.get("//the device you want to work with");
if (device != null) {
mUsbManager.requestPermission(device, mPermissionIntent);
}
And now you will need endpoints, simply send an APDU (smartcard command) over the bulk-out endpoint and expect to receive a response APDU over the bulk-in endpoint.
Code to get endpoints ::
UsbEndpoint epOut = null, epIn = null;
UsbInterface usbInterface;
UsbDeviceConnection connection = mUsbManager.openDevice(device);
for (int i = 0; i < device.getInterfaceCount(); i++) {
usbInterface = device.getInterface(i);
connection.claimInterface(usbInterface, true);
for (int j = 0; j < usbInterface.getEndpointCount(); j++) {
UsbEndpoint ep = usbInterface.getEndpoint(j);
if (ep.getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
if (ep.getDirection() == UsbConstants.USB_DIR_OUT) {
// from host to device
epOut = ep;
} else if (ep.getDirection() == UsbConstants.USB_DIR_IN) {
// from device to host
epIn = ep;
}
}
}
}
To send commands use this :
public void write(UsbDeviceConnection connection, UsbEndpoint epOut, byte[] command) {
result = new StringBuilder();
connection.bulkTransfer(epOut, command, command.length, TIMEOUT);
//For Printing logs you can use result variable
for (byte bb : command) {
result.append(String.format(" %02X ", bb));
}
}
And to read data or send binary read you can use this code:
public int read(UsbDeviceConnection connection, UsbEndpoint epIn) {
result = new StringBuilder();
final byte[] buffer = new byte[epIn.getMaxPacketSize()];
int byteCount = 0;
byteCount = connection.bulkTransfer(epIn, buffer, buffer.length, TIMEOUT);
//For Printing logs you can use result variable
if (byteCount >= 0) {
for (byte bb : buffer) {
result.append(String.format(" %02X ", bb));
}
//Buffer received was : result.toString()
} else {
//Something went wrong as count was : " + byteCount
}
return byteCount;
}
Now let's take an example of this command like the one here: 62000000000000000000 How you can send this is :
write(connection, epOut, "62000000000000000000");
Now after you have successfully sent the APDU command, you can read the response using :
read(connection, epIn);
And receive something like
80 18000000 00 00 00 00 00 3BBF11008131FE45455041000000000000000000000000F1
Now the response received in the code here will be in the result variable of read() method.And likewise you can write your own commands for communicating.

Sadly there is no abstraction layer like PC/SC in the native Android system. But you can utilize Android USB library to talk directly to the USB smart card reader.

How to record high quality audio from USB microphone without external libraries

I am struggling on how to capture the audio stream from connected USB microphone. I have tried to use the MediaCapture with MediaRecorder.AudioSource.MIC as source which worked but recording quality isn't quite usable for me and you can't be sure if the audio source is really USB or the built in device microphone. What I need is to use the USB audio feature but so far I am unable to make any progress.
To use third-party libraries is overkill for me since I need to only receive the stream of audio data from the microphone, the rest of the processing is already done and working, only the audio source is the issue.
What I need to do is:
Check if there is USB microphone connected to the device.
Find out what characteristics this device has (supported sampling rates, channels etc.)
Record audio data
What I've done so far:
Generate a list of connected USB device which class is UsbConstants.USB_CLASS_AUDIO
private static final String ACTION_USB_PERMISSION = PACKAGE_NAME + ".USB_PERMISSION";
private UsbManager mUsbManAndroid;
private Map<String, UsbDevice> mAndroidDeviceMap;
private PendingIntent mPermissionIntent;
private ArrayList<UsbDeviceListItem> getUSBDevicesList() {
// Enumerate USB devices
mAndroidDeviceMap = mUsbManAndroid.getDeviceList();
ArrayList<UsbDeviceListItem> usbDevicesList = new ArrayList<>();
for (String key : mAndroidDeviceMap.keySet()) {
UsbDevice device = mAndroidDeviceMap.get(key);
// Check the device class
if (device.getDeviceClass() == UsbConstants.USB_CLASS_AUDIO) {
usbDevicesList.add(usbDeviceToListItem(key, device));
} else if (device.getDeviceClass() == UsbConstants.USB_CLASS_PER_INTERFACE) {
UsbInterface interface;
for (int i = 0; i < device.getInterfaceCount(); i++) {
// Check if at least one interface is audio
interface = device.getInterface(i);
if (interface != null && interface.getInterfaceClass() == UsbConstants.USB_CLASS_AUDIO) {
usbDevicesList.add(usbDeviceToSysBusUsbDevice(key, device));
break;
}
}
}
}
/////////////////////////////////////////////////////////
// Here goes some code to identify the device using
// linux shell commands if device SDK version is older
// than 21 (Lollipop). In older versions of Android
// we can't get device's Vendor and Device names using
// Android API, we need to use some linux shell commands.
/////////////////////////////////////////////////////////
return usbDevicesList;
}
Request permission for selected usb device from the list:
mUsbDeviceList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
UsbDeviceListItem usbDeviceItem = (UsbDeviceListItem) mUsbDeviceList.getItemAtPosition(i);
UsbDevice device = mAndroidDeviceMap.get(usbDeviceItem.getDevicePath());
manager.requestPermission(device, mPermissionIntent);
}
});
Permission broadcast receiver:
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (ACTION_USB_PERMISSION.equals(action)) {
synchronized (this) {
UsbDevice device = intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
if(device != null){
streamFromUsbDevice(device)
}
}
else {
Toast.makeText(SensorActivity.this, "Permission denied for device " + device,
Toast.LENGTH_SHORT).show();
}
}
}
}
};
Sample method for reading data from the USB device
private void streamFromUSBDevice(UsbDevice device) {
UsbEndpoint endpoint;
UsbInterface usbInterface;
////////////////////////////////////////////////////////////////
// Here was code for finding the first audio interface with its
// endpoint. But because I failed to make it work I was manually
// getting them by index.
////////////////////////////////////////////////////////////////
usbInterface = device.getInterface(2);
endpoint = usbInterface.getEndpoint(0);
if (endpoint == null) {
Log.i(TAG, getString(R.string.endpoint_not_found));
notifyUser(R.string.endpoint_not_found);
return;
}
Log.i(TAG, R.string.connecting_to_usb_device);
notifyUser(R.string.connecting_to_usb_device);
UsbDeviceConnection connection = manager.openDevice(device);
connection.claimInterface(usbInterface, true);
while (true) {
if (!isRecording) {
// Close the connection to the usb device
connection.close();
notifyUser(R.string.status_idle);
break;
}
UsbRequest request = new UsbRequest();
request.initialize(connection, endpoint);
byte[] buffer = new byte[endpoint.getMaxPacketSize()];
final ByteBuffer buf = ByteBuffer.wrap(buffer);
Log.i(TAG, "Requesting queue...");
if (!request.queue(buf, buffer.length)) {
Log.e(TAG, getString(R.string.error_queue_request)));
notifyUser(R.string.error_queue_request);
isRecording = false;
break;
}
Log.i(TAG, "Requesting response...");
final UsbRequest response = connection.requestWait();
if (response == null) {
Log.e(TAG, "Null response!");
notifyUser(R.string.null_response);
isRecording = false;
break;
}
final int nRead = buf.position();
if (nRead > 0) {
Log.i(TAG, "Streaming " + nRead + " bytes to UI");
Bundle args = new Bundle();
args.putShortArray(ARG_RECORDED_DATA, byte2short(buffer));
sendMessageToUI(SHOW_AUDIO_DATA_PACKET, args, null);
} else {
Log.e(TAG, "No data in buffer!");
notifyUser(R.string_empty_buffer);
isRecording = false;
break;
}
}
}
What I am getting from this is that request.queue() is always returning false.
I have also attempted to use the connection.bulkTransfer(endpoint, buffer, buffer.length, 0); method but the result is always -1.
If someone was in similar situation please help.
P.S. The error I am receiving in the log is: UsbRequestJNI: request is closed in native_queue.

Reading data from Arduino UNO R3 kit

I'm trying to read the data already stored by me in the Arduino kit, I'm using the physicaloid library to achieve this. I tested the kit (reading data) by connecting it to my PC using the Type B USB cable provided by Arduino itself and using Tera Term. The data begins to transfer after I press '#' on the keyboard (specific to our implementation).
But when I connect it my Android tablet and use the test project by physicaloid to open a device and start communicating, every time I click 'open' it shows a Toast saying it cannot open. I give permission to access the USB device every time it prompts me. Here is the sample program which I had created to read the data:
if(mPhysicaloid.open()){
Toast.makeText(getBaseContext(), "communicating", Toast.LENGTH_SHORT).show();
String signalToStart = new String("#");
byte[] bufToWrite = signalToStart.getBytes();
mPhysicaloid.write(bufToWrite, bufToWrite.length);
byte[] buf = new byte[255];
mPhysicaloid.read(buf);
String data = new String(buf);
tvResult.setText(data);
mPhysicaloid.close();
}
else
Toast.makeText(getBaseContext(), "no communication with device", Toast.LENGTH_LONG).show();
Now here's what I want to know about the data coming from the Arduino USB cable: is it in the RS232 format where the Android device is not able to understand (I don't know, I may be making a blunder here by asking this data format) or is it in the USB data format that is suitable for the Android device to understand? Please help, I have searched over this the whole day. What can I do to open the device and communicate?

I finally got the idea of reading the data from serial USB device. So I thought I'd share it:
First, get all the USB devices attached (if more than one) and get a suitable interface and search for endpoints to communicate with. While initializing the USB device make sure you consider the USB device which you really want to communicate with. You can do that by considering product id and Vendor id.
The code for doing the above described..
private boolean searchEndPoint() {
usbInterface = null;//class level variables, declare these.
endpointOut = null;
endpointIn = null;
Log.d("USB","Searching device and endpoints...");
if (device == null) {
usbDevices = usbManager.getDeviceList();
Iterator<UsbDevice> deviceIterator = usbDevices.values().iterator();
while (deviceIterator.hasNext()) {
UsbDevice tempDevice = deviceIterator.next();
/**Search device for targetVendorID(class level variables[vendorId = SOME_NUMBER and productId=SOME_NUMBER] which u can find) and targetProductID.*/
if (tempDevice .getVendorId() == vendorId) {
if (tempDevice .getProductId() == productId) {
device = tempDevice ;
}
}
}
}
if (device == null){
Log.d("USB","The device with specified VendorId and ProductId not found");
return false;
}
else
Log.d("USB","device found");
/**Search for UsbInterface with Endpoint of USB_ENDPOINT_XFER_BULK,
*and direction USB_DIR_OUT and USB_DIR_IN
*/
try{
for (int i = 0; i < device.getInterfaceCount(); i++) {
UsbInterface usbif = device.getInterface(i);
UsbEndpoint tOut = null;
UsbEndpoint tIn = null;
int tEndpointCnt = usbif.getEndpointCount();
if (tEndpointCnt >= 2) {
for (int j = 0; j < tEndpointCnt; j++) {
if (usbif.getEndpoint(j).getType() == UsbConstants.USB_ENDPOINT_XFER_BULK) {
if (usbif.getEndpoint(j).getDirection() == UsbConstants.USB_DIR_OUT) {
tOut = usbif.getEndpoint(j);
} else if (usbif.getEndpoint(j).getDirection() == UsbConstants.USB_DIR_IN) {
tIn = usbif.getEndpoint(j);
}
}
}
if (tOut != null && tIn != null) {
/** This interface have both USB_DIR_OUT
* And USB_DIR_IN of USB_ENDPOINT_XFER_BULK
*/
usbInterface = usbif;
endpointOut = tOut;
endpointIn = tIn;
}
}
}
if (usbInterface == null) {
Log.d("USB","No suitable interface found!");
return false;
} else {
Log.d("USB","Suitable interface found!");
return true;
}
}catch(Exception ex){
ex.printStackTrace();
return false;
}
}
Now you have a device, USB interface, and endpoints ready for communication. Now it's time to establish a connection between your Android device and USB device.
Below is the code for this (and checking whether the connection is up and communicating):
private boolean checkUsbCOMM() {
/**Value for setting request, on the USB connection.*/
final int RQSID_SET_CONTROL_LINE_STATE = 0x22;
boolean success = false;
Log.d("USB","Checking USB Device for communication: ");
try{
Boolean permitToRead = SUSBS_usbManager.hasPermission(SUSBS_device);
if (permitToRead) {
//class level variable(connection, usbManager : declare it)
connection = usbManager.openDevice(device);
if (connection != null) {
connection.claimInterface(usbInterface, true);
int usbResult;
usbResult = connection.controlTransfer(0x21, //requestType
RQSID_SET_CONTROL_LINE_STATE, //SET_CONTROL_LINE_STATE(request)
0, //value
0, //index
null, //buffer
0, //length
500); //timeout = 500ms
Log.i("USB","controlTransfer(SET_CONTROL_LINE_STATE)[must be 0 or greater than 0]: "+usbResult);
if(usbResult >= 0)
success = true;
else
success = false;
}
}
else {
/**If permission is not there then ask for permission*/
usbManager.requestPermission(device, mPermissionIntent);
Log.d("USB","Requesting Permission to access USB Device: ");
}
return success;
}catch(Exception ex){
ex.printStackTrace();
return false;
}
}
Voila, the USB device is now able to communicate. So let's read using a separate thread:
if(device!=null){
Thread readerThread = new Thread(){
public void run(){
int usbResult = -1000;
int totalBytes = 0;
StringBuffer sb = new StringBuffer();
String usbReadResult=null;
byte[] bytesIn ;
try {
while(true){
/**Reading data until there is no more data to receive from USB device.*/
bytesIn = new byte[endpointIn.getMaxPacketSize()];
usbResult = connection.bulkTransfer(endpointIn,
bytesIn, bytesIn.length, 500);
/**The data read during each bulk transfer is logged*/
Log.i("USB","data-length/read: "+usbResult);
/**The USB result is negative when there is failure in reading or
* when there is no more data to be read[That is :
* The USB device stops transmitting data]*/
if(usbResult < 0){
Log.d("USB","Breaking out from while, usb result is -1");
break;
}
/**Total bytes read from the USB device*/
totalBytes = totalBytes+usbResult;
Log.i("USB","TotalBytes read: "+totalBytes);
for(byte b: bytesIn){
if(b == 0 )
break;
else{
sb.append((char) b);
}
}
}
/**Converting byte data into characters*/
usbReadResult = new String(sb);
Log.d("USB","The result: "+usbReadResult);
//usbResult holds the data read.
} catch (Exception ex) {
ex.printStackTrace();
}
}
};
/**Starting thread to read data from USB.*/
SUSBS_readerThread.start();
SUSBS_readerThread.join();
}
For permission, make sure you add a PendingIntent as well add the permission to your manifest.
AndroidManifest : <uses-feature android:name="android.hardware.usb.host" />
PendingIntent:
private PendingIntent mPermissionIntent;
private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
mPermissionIntent = PendingIntent.getBroadcast(MainActivity.this,
0, new Intent(ACTION_USB_PERMISSION), 0);
/**Setting up the Broadcast receiver to request a permission to allow the APP to access the USB device*/
IntentFilter filterPermission = new IntentFilter(ACTION_USB_PERMISSION);
registerReceiver(mUsbReceiver, filterPermission);

Compile and link against libusb for android

I consider trying to compile a certain C-programm which allows the control of Gembird SilverShield power outlets via USB for android. On my android HDMI TV-stick this would be very useful. There is an open project for this. It works under Linux and depends on libusb. The target platform is android ICS. I want to develop on Ubuntu Linux. What are the chances I get it working? What are the required steps. Setup android SDK, NDK, crosscompiler ... There is an older question here, related to libusb on android but no information how. Is it maybe easier to port the application to androids own usb library?

Libusb can work on a non-rooted android (provided the device supports USB host ... this is VERY important as not all devices do). You need to use the standard android USB stack. You can then get a device descriptor from the USBDevice and pass that over to libusb.
Unfortunately you also need to modify libusb. Fortunately other people have explained how you need to modify LibUSB.
LibUSB has been modified here.
Good luck!
Edit:
First you need to define a broadcast receiver:
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver()
{
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)
{
UsbDeviceConnection deviceConnection = mUsbManager.openDevice( device );
Log.d( "USB", deviceConnection.getSerial() );
}
}
else
{
Log.d( "USB", "permission denied for device " + device);
}
}
}
}
}
Now you need to create a USBManager and enumerate the devices:
mUsbManager = (UsbManager) getSystemService( Context.USB_SERVICE );
HashMap< String, UsbDevice > stringDeviceMap = mUsbManager.getDeviceList();
Collection< UsbDevice > usbDevices = stringDeviceMap.values();
mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent( ACTION_USB_PERMISSION ), 0 );
IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
registerReceiver( mUsbReceiver, filter );
Iterator< UsbDevice > usbDeviceIter = usbDevices.iterator();
while( usbDeviceIter.hasNext() )
{
if ( USBDeviceValid( usbDevice ) )
{
// Request permission to access the device.
mUsbManager.requestPermission( usbDevice, mPermissionIntent );
// Open the device.
UsbDeviceConnection connection = mUsbManager.openDevice( usbDevice );
int fd = connection.getFileDescriptor();
// Now pass the file descriptor to libusb through a native call.
}
}
Edit 2:
Getting libusb to build is just a matter of putting the files somewhere handy (I put them in jni/libusb) and then adding the following lines to your Android.mk:
include $(CLEAR_VARS)
LOCAL_MODULE := libusb
LOCAL_SRC_FILES := libusb/core.c libusb/descriptor.c libusb/io.c libusb/sync.c libusb/os/linux_usbfs.c
LOCAL_LDLIBS := -llog
include $(BUILD_SHARED_LIBRARY)

The solution I implemented is to open the USB device using the Java APIs and then using the file descriptor with libusb.I used libusb from openni project by primesense(https://github.com/OpenNI/OpenNI2)
Code bits:
Opening the device(Using swig):
int LibUsbAndroid::android_open(libusb_device *device, libusb_device_handle **devHandle)
{
int fd = USBJNICallbacks::getCallback()->getDeviceFd(device->bus_number, device->device_address);
__android_log_print(ANDROID_LOG_VERBOSE,"USB","Got FD:%d",fd);
if(fd==-1)
{
__android_log_print(ANDROID_LOG_ERROR,"USB","android_open, bad fd");
return -1;
}
return libusb_open(device, devHandle, fd);
}
Opening the device in JAVA code(Not running on main thread!):
public int getDeviceFd(int busNumber, int deviceAddress) {
UsbDevice device = findDevice(busNumber, deviceAddress);
if(device!=null)
{
mReceivedPermission = false;
PermissionRequester pr = new PermissionRequester(device);
pr.run();
if(!mUsbManager.hasPermission(device))
{
Log.v("USB", "Requesting permissiom to device");
mPermissionIntent = PendingIntent.getBroadcast(mContext, 0, new Intent(ACTION_USB_PERMISSION), 0);
IntentFilter filterPermission = new IntentFilter(ACTION_USB_PERMISSION);
mContext.registerReceiver(mUsbPermissionReceiver, filterPermission);
mUsbManager.requestPermission(device, mPermissionIntent);
}
else
{
Log.v("USB", "Already has permission");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
mReceivedPermission = true;
Log.v("USB", "Opening device");
OpenDevice od = openDevice(device);
Log.v("USB", "Adding to open devices");
mOpenDevices.put(""+busNumber+"/"+deviceAddress, od);
}
Log.v("USB", "Waiting for permission");
waitForPermissionResult();
OpenDevice od = mOpenDevices.get(""+busNumber+"/"+deviceAddress);
if(od!=null)
{
Log.v("USB", "Getting FD");
int result = od.mConnection.getFileDescriptor();
Log.i("USB","USB File desc:"+result);
return result;
}
else
{
Log.v("USB", "Error getting FD");
return -1;
}
}
return -1;
}
Permission handling code:
private BroadcastReceiver mUsbPermissionReceiver=new BroadcastReceiver(){
#Override
public void onReceive(Context context, Intent intent) {
Log.v("USB", "Received permission result");
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)) {
Log.v("USB", "Received permission result OK");
if(device != null){
Log.v("USB", "Device OK");
mContext.unregisterReceiver(this);
Log.v("USB", "Openning device");
OpenDevice od = openDevice(device);
Log.v("USB", "Adding to open device list");
mOpenDevices.put(""+od.mBus+"/"+od.mAddress,od);
Log.v("USB", "Received permission is true");
mReceivedPermission = true;
}
else {
Log.d(TAG, "permission denied for device " + device);
}
}
}
}
}
};
Open function:
public OpenDevice openDevice(UsbDevice device) {
UsbDeviceConnection connection = mUsbManager.openDevice(device);
Log.i("USB","Device name="+device.getDeviceName());
int bus = getBusNumber(device.getDeviceName());
int address = getAddress(device.getDeviceName());
return new OpenDevice(device, connection, bus, address);
}
USB lib change(core.c):
int API_EXPORTED libusb_open(libusb_device *dev,
libusb_device_handle **handle, int fd)
{
struct libusb_context *ctx = DEVICE_CTX(dev);
struct libusb_device_handle *_handle;
size_t priv_size = usbi_backend->device_handle_priv_size;
int r;
usbi_dbg("open %d.%d", dev->bus_number, dev->device_address);
_handle = malloc(sizeof(*_handle) + priv_size);
if (!_handle)
return LIBUSB_ERROR_NO_MEM;
r = usbi_mutex_init(&_handle->lock, NULL);
if (r) {
free(_handle);
return LIBUSB_ERROR_OTHER;
}
_handle->dev = libusb_ref_device(dev);
_handle->claimed_interfaces = 0;
memset(&_handle->os_priv, 0, priv_size);
r = usbi_backend->open(_handle,fd);
if (r < 0) {
usbi_dbg("open %d.%d returns %d", dev->bus_number, dev->device_address, r);
libusb_unref_device(dev);
usbi_mutex_destroy(&_handle->lock);
free(_handle);
return r;
}
usbi_mutex_lock(&ctx->open_devs_lock);
list_add(&_handle->list, &ctx->open_devs);
usbi_mutex_unlock(&ctx->open_devs_lock);
*handle = _handle;
/* At this point, we want to interrupt any existing event handlers so
* that they realise the addition of the new device's poll fd. One
* example when this is desirable is if the user is running a separate
* dedicated libusb events handling thread, which is running with a long
* or infinite timeout. We want to interrupt that iteration of the loop,
* so that it picks up the new fd, and then continues. */
usbi_fd_notification(ctx);
return 0;
}
op_open(libusb_fs.c) change:
static int op_open(struct libusb_device_handle *handle, int fd)
{
struct linux_device_handle_priv *hpriv = _device_handle_priv(handle);
char filename[PATH_MAX];
_get_usbfs_path(handle->dev, filename);
usbi_dbg("opening %s", filename);
hpriv->fd = fd;
if (hpriv->fd < 0) {
if (errno == EACCES) {
usbi_err(HANDLE_CTX(handle), "libusb couldn't open USB device %s: "
"Permission denied.", filename);
usbi_err(HANDLE_CTX(handle),
"libusb requires write access to USB device nodes.");
return LIBUSB_ERROR_ACCESS;
} else if (errno == ENOENT) {
usbi_err(HANDLE_CTX(handle), "libusb couldn't open USB device %s: "
"No such file or directory.", filename);
return LIBUSB_ERROR_NO_DEVICE;
} else {
usbi_err(HANDLE_CTX(handle),
"open failed, code %d errno %d", hpriv->fd, errno);
return LIBUSB_ERROR_IO;
}
}
return usbi_add_pollfd(HANDLE_CTX(handle), hpriv->fd, POLLOUT);
}

Even if you get it compiled, Android is probably not going to let you access the USB device through libusb unless your device is rooted. If it is feasible to port your app to Android's native USB stack, that would almost certainly be a more stable solution.

You can also try to use android serial port api
Here is example of serial port init.
private FileDescriptor mFd;
private FileInputStream mFileInputStream;
private FileOutputStream mFileOutputStream;
public SerialPort(File device, int baudrate, int flags) throws SecurityException, IOException {
/* Check access permission */
if (!device.canRead() || !device.canWrite()) {
try {
/* Missing read/write permission, trying to chmod the file */
Process su;
su = Runtime.getRuntime().exec("/system/bin/su");
String cmd = "chmod 666 " + device.getAbsolutePath() + "\n"
+ "exit\n";
su.getOutputStream().write(cmd.getBytes());
if ((su.waitFor() != 0) || !device.canRead()
|| !device.canWrite()) {
throw new SecurityException();
}
} catch (Exception e) {
e.printStackTrace();
throw new SecurityException();
}
}
mFd = open("/dev/ttyACM0", 9600, 0);
if (mFd == null) {
Log.e(TAG, "native open returns null");
throw new IOException();
}
mFileInputStream = new FileInputStream(mFd);
mFileOutputStream = new FileOutputStream(mFd);
}
So did it with use devices on USB host.

Reading raw mouse data on android

In my Android app, I read the values from a 3DConnexion SpaceNavigator via USB-OTG to control an AR.Drone.
Now I want to do the same with a mouse. However, Android is grabbing the mouse and presenting a mouse-cursor. When I write a device-filter with the vendor and product ID of the mouse, I do not get it like with the SpaceNavigator (strangely, both are HID -- I get no cursor with the SpaceNavigator).
Is there a way to get the raw mouse data without the cursor?
Would be perfect with stock Android. but I would also consider altering the ROM for that.

As soon as your Application claims the Mouse (as a USB HID device while being Host), Android should hide the cursor and you can read the raw data. This should work on stock android, but your device has to support USB Host mode and a USB OTG cable will be needed to connect the mouse.
Basic procedure:
enumerate devices
ask for permission to access the USB device
claim the device
read a data package from the HID endpoint
parse the X and Y position, button clicks and scroll wheel rotation from the data package
Example Code that works for me (Android 5.0):
UsbManager usbManager;
UsbDevice usbDevice;
private void connect() {
this.usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();
// just get the first enumerated USB device
Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
if (deviceIterator.hasNext()) {
this.usbDevice = deviceIterator.next();
}
if (usbDevice == null) {
Log.w(TAG, "no USB device found");
return;
}
// ask for permission
final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {
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
Log.i(TAG, "permission granted. access mouse.");
// repeat in a different thread
transfer(device);
}
}
else {
Log.d(TAG, "permission denied for device " + device);
}
}
} else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
UsbDevice device = (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
if (device != null) {
// TODO:
// call your method that cleans up and closes communication with the device
// usbInterface.releaseInterface();
// usbDeviceConnection.close();
}
}
}
};
PendingIntent mPermissionIntent = PendingIntent.getBroadcast(context, 0, new Intent(ACTION_USB_PERMISSION), 0);
IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
context.registerReceiver(mUsbReceiver, filter);
usbManager.requestPermission(usbDevice, mPermissionIntent);
}
private void transfer(UsbDevice device) {
int TIMEOUT = 0;
boolean forceClaim = true;
// just grab the first endpoint
UsbInterface intf = device.getInterface(0);
UsbEndpoint endpoint = intf.getEndpoint(0);
UsbDeviceConnection connection = this.usbManager.openDevice(device);
connection.claimInterface(intf, forceClaim);
byte[] bytes = new byte[endpoint.getMaxPacketSize()];
connection.bulkTransfer(endpoint, bytes, bytes.length, TIMEOUT);
// depending on mouse firmware and vendor the information you're looking for may
// be in a different order or position. For some logitech devices the following
// is true:
int x = (int) bytes[1];
int y = (int) bytes[2];
int scrollwheel = (int) bytes[3]
// call a listener, process your data ...
}