Develop Reference

hidraw set-report/send-report doesn't work with Android 6.x

I have a bluetooth hid device that I need to communicate with. Target platform is Android 5.x+. Currently testing on Nexus 7 2013 tablet.
My code works fine on android 5.x, I am able to receive, send and set reports on Android 5.x.
On Android 6.x, I am only able to receive reports sent by device, but I am not able to send or set reports. It looks like my set/send report requests are silently ignored by HID/BT stack.
The code that talks to /dev/hidraw* nodes runs as a native daemon as root.
Are there any new requirements to be able to set/send reports to Bluetooth hid devices on Android 6.x? Is there any changes I could make to AOSP to allow this to work?
[Update]
Logcat says:
05-17 11:22:56.085 2455-4061/com.android.bluetooth E/bt_btif: uhid_event: Invalid size read from uhid-dev: 4108 != 4
I do not understand how reading from uhid will return only 4 bytes! First 4 bytes are supposed to contain only the type of event. Is there any scenario that will result in a read() of less than sizeof(struct uhid_event) bytes?
Could this indicate a bug in uhid driver?

I checked available kernel sources and found that hidraw driver does not contain usable source to feed reports to /dev/hidraw* nodes
I also found that Bluedroid correctly receives and sends reports internally.
Simplest method to get/set/send reports I found was to modify bluedroid to communicate directly with my App for vendor-specific reports. I integrated my daemon into Bluedroid directly.

USB-Webcam on Android 4.4+

I am into a new project which requires me to use a USBconnected "Webcam".
The whole fun should run on Android 4.4.
my little story was:
I try multiple apps which do this - all work on both my testing devices
adapting some NDK lib that directly uses /dev/video0. This didnt work due to read-permission that was not granted in a new File("dev/video0").canRead() check. Although my unix permissions are correct, this seems to not work due to some new check on Android 4.4. (the whole thing was suggested here: Connect Android phone to a USB Web camera )
next: discover the UsbAccessory API that supposedly easens a lot of the above.
´find no documentation or anything about how to correctly handle a webcam
I still try, but don't come further than finding no device via
usbManager.getAccessory();
I've also tried to discover devices by filtering for a USB_ATTACHED broadcast but nothing triggers.
So I am starting to ask myself how the hell do others find the devices & communicate with them to get the pictures?
Anyone has sources from which i could learn, or a tutorial or something?
Little update from my side:
- I've gotten access by using the Android USB Host API e.g. UsbDevice instead of UsbAccessory.
- I have the connection and everything setup fine, and can now send binary data to my webcam and supposedly receive.
I can now send controlCommands via connection.controlTransfer(...) or use a "UsbRequest" in order to receive data.
However, I couldn't find any documentation to "make the camera submit pictures" to me. My Endpoint is of type XFER_INT (=interrupts).
I am continuing to try sending out various commands (e.g. binary values) but haven't had any success so far.

Android Bluetooth IOException:connection refused

Alright here's the deal. I got two Galaxy Nexus phones both with bluetooth enabled.
I've written a bluetooth connection management app that I use for device discovery and connectivity. It also outputs all the available UUIDs the devices can support.
Looking from http://www.bluetooth.org/Technical/AssignedNumbers/service_discovery.htm the following standard UUIDs are exposed from Galaxy Nexus devices.
0x1116 - NAP
0x112f - PBAP (Phonebook Access Profile)
0x111f - HFP (Hands free)
0x1105 - OPP (Object Push Profile)
0x1112 - HSP (Headset Profile)
0x110c - AVRCP
0x110a - A2DP
I am trying to connect via the OPP profile (UUID 00001105-0000-1000-8000-00805F9B34FB) and push objects (files) between the devices. I've gone though the entire Android API documentation on how to discover, pair/bond (threading etc.) and manage all bluetooth connections. I've managed to successfully connect and talk to a legacy board device via the SPP (0x1101) profile.
However, when I try to use socket.connect() between the two galaxy nexus phones, the pairing dialog shows up and I click Pair button on both devices. After that, I immediately get a Connection Refused IOException. Note that after pairing has occurred once I never get asked again which makes sense since the secure link is cached.
If I can't connect to these standard profiles using these standard UUIDs why are they exposed? How can I connect from my app to any of these profiles and interact with them? Is it because my app is not somehow trusted? What's weird is that even the Share functionality on Android does not work at all either. Is this something completely broken on Android?
Please avoid giving me hints to use the "well known UUID SPP one 0x1101" like the docs say. This is not what I want. I have a fairly good understanding of how this stuff works and I am looking for a real solution or explanation of the problem.
I've seen the typical "reflection" solution but I do not understand why is this still a problem on Android? Why do people use reflection to make this work? Can we file a bug on Android to fix this?
If those UUIDs are standard any app should be able to connect and interact with them. Why is this an issue and why do I get this exception?
Thanks in advance.
UPDATE
So for some reason the object push in the Android system started working. I actually attempted to connect via my app and it was not working. Then, I went to the Contacts app and tried to share a contact which magically worked. Then, I went back to my app and it now it works...wow. That is very weird and there must be an explanation to this.

I ran into this same issue and managed to find a solution that worked for me.
In my case I using three different test devices (Nexus 5, Galaxy S4, Note 2) and for some reason, the Note 2 wouldn't connect to my Bluetooth module yet the other two would.
The reasoning I've found is that Bluetooth drivers vary, and slightly different connection methods are needed to create a connection between different devices.
The three methods I use are called 'Secure', 'Insecure' and 'Reflection method'/'hax'.
switch(connType)
{
case Secure:
tmpSocket = device.createRfcommSocketToServiceRecord(_uuid);
break;
case Insecure:
tmpSocket = device.createInsecureRfcommSocketToServiceRecord(_uuid);
break;
case Hax:
Method createSocket = device.getClass().getMethod("createRfcommSocket", new Class[] {int.class});
tmpSocket = (BluetoothSocket)createSocket.invoke(device, Integer.valueOf(1));
break;
}
In my case, the Secure mode worked for both the Nexus 5 and Galaxy S4 however it didn't work for the Note 2.
After some testing I discovered the Note 2 only works using 'Insecure' mode, so to cater to this, I basically attempt a connection and cycle through the different modes if necessary. When attempting a different connection mode I simply prompt 'retrying connection'. So, if the connection fails using secure, then I will attempt using Insecure and then using the reflection method.
I haven't run into the case where one of these three methods haven't worked.

Have you tried using a nonstandard profile? i.e. a custom UUID just for your app. This will also help you know your are (most likely) only connecting to your own app rather than some other app that is registered with the same profile.
From my experience, Bluetooth pairing is very buggy for the first pair attempt. However, using a custom UUID helps this somewhat.
The reflection method (I think) was originally an attempt to fix a bug with a specific device, however I think some people found success in using it elsewhere as well. The device was called the Spica or something similar.
As one of the comments also posted, I would also try connecting again after failing.
Basically write code that plans to fail the first attempt, but then the code tries to connect again in 5 seconds if there was a failure.
These are imperfect solutions but Bluetooth implementation on Android is also imperfect (IMHO). Hope that helps
EDIT
Based on the question update and comments:
I agree something is definitely buggy. Part of the problem I think is the BT drivers vary and each has a different BT stack with different quirks. I also found a question that makes use of both the reflection method AND custom UUID, AND other standard methods. This seems extreme to me but it does cover the most ground. Unfortunately as app developers we have no control over the low level stack/code/drivers.
I have found with my two Bluetooth sharing apps that the first pairing is always tricky.
I'm glad to know it's not just me.

communication issue between ACR122U-A2NR (nfc card reader) with samsung S2(Android 2.3.4)?

I am trying to send following NDEF message from a windows application to Android phone through ACR122U-A2NR.
43200001000000010100000027D101235402656E53746172742C4775696C6C61756D6520424552544541552C313233342C456E64
On the windows end I'm sending NDEF message using following sequence of commands.
(For this I use winscard.dll).
"FF0000002DD48C0100000000004001FE0FBBBAA6C9890000000000000000FFFF01FE0FBBBAA
6C98900000646666D01011000"
"FF00000002D486"
"FF00000015D48E0520060F636F6D2E616E64726F69642E6E7070"
"FF00000036D48E43200001000000010100000027D101235402656E53746172742C4775696C6C6
1756D6520424552544541552C313233342C456E64"
Application on Nexus S android 2.3.4 is working fine. While same is not working on Samsung SII android 2.3.4.
In case of Nexus S command #4 returns "D58F00" (Success)
In case of SII above command returns "D58F25". Where "0x25" is error code for :
DEP protocol:Invalid device state the system is in state which does not allow this operation

Are you trying this with ACS SDK or an alternative?
Have you checked nfctools library? http://www.grundid.de/nfc. I think they have better support for P2P communications since it fully implement the android protocols specification (although still have some bugs).

Android WiFi Direct Demo Issues

im testing the new technology wifi direct and im having some issues using
the wifi direct demo from the samples that come with the android-sdk.
So, I have two devices A and B, both with android 4.0.3.
First, from device A, I send a file to B. Nothing wrong here, B
receives the file.
Then A disconnects from B.
Now, from device B I try to send a file to A.
But the device that receives the file is B, instead of A.
To fix, i need to turn off and on both devices...
Also, sometimes when i click disconnect and try to
connect again, connection fails and i have to disable and
enable wifi direct...
Anyone else experiencing this?
Is it because the new technology is not mature yet or maybe
something wrong with my build/driver/etc or maybe this demoapp
doesnt support two-way sharing.
Any ideas and/or explanations would be apreciated.

When providing a WifiP2pConfig instance to the connect() function, you can set the groupOwnerIntent property of this configuration object as follows:
WifiP2pConfig config = new WifiP2pConfig();
config.deviceAddress = "..."; // insert ip here
config.groupOwnerIntent = 0;
config.wps.setup = WpsInfo.PBC;
manager.connect(..., config, ...);
From the android reference:
This (the groupOwnerIntent) is an integer value between 0 and 15 where
0 indicates the least inclination to be a group owner and 15 indicates
the highest inclination to be a group owner.
Furthermore, the demo probably repeatedly sends the file to the same device because there is always made a socket connection to the ip-address obtained from:
WifiP2pInfo.groupOwnerAddress
If you would like to support bidirectional communication, the first step in setting this up would be sending the ip-address of the non group owner to the group owner.
As far as the disconnect/reconnect problem goes, I seem to have the same inconsistencies with Android 4.0.2 devices.

I have been trying for a while to transfer files between two devices using wifi direct. I have use the Android SDK WifiDirectDemo as base. My experience:
GO address is always the same (at least in Samsung Nexus), but this is not really a problem, because you can use this to know who is the server (or client).
Another strange thing was that MAC address of devices were different when you got it from Android WifiManager and when you read it from "/proc/net/arp" file.
At the end I did it, and you can see the code here.
I hope it helps you!

I have been struggling with the same problem lately. I suppose this is an OS issue. To give you a brief background, I have installed Wi-Fi Direct application to both devices with different OS versions, one with OS 4.0.1 and one with OS 4.0.2. The connection fails from time to time when I disconnect and reconnect the devices. It goes same while searching for devices too. But the thing is, this only happens on the device with OS 4.0.2. Other device does not crash or disconnect.
While searching for that problem, I have found the links below. People discussed about that and they share the same idea. Apparently this is an OS 4.0.2 issue. I am not sure if it is the same for OS 4.0.3 but there is no problem with the previous version OS 4.0.1 for sure.
Here are the links:
http://code.google.com/p/android/issues/detail?id=24402
http://osdir.com/ml/android-platform/2012-01/msg00226.html