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.

Cannot set temperature interval on sensortag

I'm creating an android application that interfaces with the texas instruments sensortag. One of the things the app needs to do is be able to change the frequency in which the temperature is reported to the app. I am able to change it through the official TI app which is great, but I cannot seem to get it working in my app.
When viewing the official app (iOS, can't run the android one?), it shows the temperature GATT service, which contains 3 characteristics. When I inspect the characteristics discovered by my app however, it only seems to find two - the data, and the notifications. Not the interval. I have attempted to construct this characteristic myself and write it however it doesn't do anything - no error, no success, just nothing.
The steps I've taken are essentially:
bluetoothGatt.discoverServices();
...
services = bluetoothGatt.getServices();
...
BluetoothGattService service = bluetoothGatt.getService(serviceUUID);
System.out.println("Characteristic = " + service.getCharacteristic(SensorTagGatt.UUID_IRT_PERI));
The output yields null. Is there something obvious I'm missing or that I should be doing that I might not be?
EDIT:
I've installed another app onto the phone written by another developer, and using this to inspect the services and characteristics available shows that it too is unable to find it, so I'm assuming there is something wrong with the android service discovery? The official iOS app is working as expected, and showing all characteristics. Unfortunately, the official android app seems to be incompatible with the version 1.5 firmware and crashes when trying to connect but I assume it too will fail to find the characteristic.
Has anyone else run into this issue and if so been able to get around it?

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.

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

Sending DTMF tones over the uplink in-call

I'm working on a project that requires my app to be able to send DTMF tones on the voice's uplink frequency during an active call.
My 2 conditions are:
We don't use a customized Android platform
We don't need to root the phone
I've spent several days doing my homework and am aware that in-call DTMF sending is not supported by the current SDK/standard APIs. However, by using the relevant classes in com.android.internal.telephony I am hoping to mimic how the native Phone app does this. I followed this site on how to use internal APIs for standard 3rd party apps.
I've also set myself up with the Android OS dev environment and am able to run the Phone app in debug mode on an emulator to figure its inner workings.
I tried various ways on a stock standard emulator but the errors I got were:
After trying to install a renamed app based on Phone.apk's source using the sharedUserId of android.uid.phone, I got:
Installation error: INSTALL_FAILED_SHARED_USER_INCOMPATIBLE
No doubt due to the fact I don't have the system cert to sign it.
After trying to write a custom app based on the relevant DTMF tone sending code from Phone.apk's source, I get the following error at setting up the PhoneFactory;
java.lang.SecurityException: Permission Denial: not allowed to send broadcast android.provider.Telephony.SPN_STRINGS_UPDATED.
No doubt due to the fact my app doesn't have the right permissions, although AndroidManifest.xml is setup with the same permissions as Phone.apk.
I'm at a loss as to what else I could try. Does anyone have any suggestions?
Thanks in advance,
Simon.

You've taken an interesting approach, and I commend your efforts. Unfortunately, there are some reserved internal privileges (evidently, such as SPN_STRINGS_UPDATED) that you aren't allowed to use as an app developer, which more or less breaks this approach. You could try removing the area of code causing this, but I'm fairly certain you will run into a blocking problem.
Hence, I'm afraid this is not possible at the moment. There's an open feature request on Android for sending DTMF tones over an existing phone call, but it has been dormant there for almost two years.
I understand that this doesn't resolve your problem, but take note that you can send DTMF tones directly after dialing a number:
Intent i = new Intent("android.intent.action.CALL",
Uri.parse("tel://" + number + "," + dtmfTones));

Simply put, you won't be able to do it without customizing at least the Phone app, which has to run as a system user in order to access the modem. In order to do this, you have to root your phone.
To meet your requirements the only possible solution is to enhance the android platform. We did just that, and already sent in our patches to the AOSP project:
https://android-review.googlesource.com/32820
https://android-review.googlesource.com/32821
We are currently waiting for the Google developers to review and accept our contribution. If you are interested, please let Google know on the various AOSP lists (android-contrib, android-platform). It will hopefully expedite the review.
Best Regards,
Gergely

You can't send DTMF tones during an active call, but you can send them when you "program" them when you initiate the call.
see the following post: https://stackoverflow.com/a/12986066/475472