Bluetooth -> service discovery failed

问题:

I'm writing an application that is able to communicate with my PC. I have used the Bluetooth functionalities of the SDK 2.1.

I can find devices, get their MAC address, create an RFCOMM socket, but when I start the connection, I get the following error message.

Service discovery failed.

1. Is it because of the UUID, which is not the same on my application and on my PC?
2. How can I get the correct UUID on my PC?

If I write a such application, is my Nexus One the client or the server?

回答1:

OK, I got the same problem, but I think I can answer a few of your questions. If your PC opened an SPP Port, for example, by using "sdptool add --channel=3 SP" your Android phone would be the client opening a socket and connecting with this socket to the server (your PC or any other Bluetooth device, for example, GPS, mouse, etc.).

You can get this information by reading the article Bluetooth, the definition of a client did I take out of this article.

If you are opening an SPP Port on the server (your PC, etc.) you are offering a standard service and there is a special UUID assigned to this service. This would be: 00001101-0000-1000-8000-00805F9B34FB if I'm not mistaken.

So I think we should get a qualified answer from an Android developer. Or ask this question on Thursday during the IRC office hours.

回答2:

Hint: If you are connecting to a Bluetooth serial board then try using the well-known SPP UUID 00001101-0000-1000-8000-00805F9B34FB. However if you are connecting to an Android peer then please generate your own unique UUID.

The Link

回答3:

Although it could be your UUID, I would also suggest you make sure the Bluetooth MAC is accurate and upper-case.

I would also suggest running hcidump -X in a terminal on the Linux box, and see if you can see any two-way traffic between your Linux machine and phone throughout the process.

回答4:

I found a way to be sure that the UUID is found on the device. On the client side, before device.createRfcommSocketToServiceRecord(uuid); add:

Process process = Runtime.getRuntime().exec("su -c 'sdptool records " + device.getAddress() + "'");
process.waitFor();

The process is frozen during 20-30 seconds, because Android is fetching services. But after, if the server is in discovery mode (if the server is an Android phone), the connection succeeds every time!

回答5:

I had the same problem when reconnecting SPP after the first connect.

This is because rfcomm channel=-1 in BluetoothService.java. I added updateDeviceServiceChannelCache() to the end of fetchRemoteUuids(), and then it worked!

回答6:

This thing happens mostly to HTC. I faced the same problem. If you first connected successfully but fail afterwards, just restart the phone and the service that failed will restart in doing so.