Android bluetooth UUID connecting APP to ANDROID

Question

I'm building an android application that keeps tracks of the Bluetooth connection on a device and triggers an alarm when they get out of range.

The Android documentation asks for a UUID in order to establish a connection.

An 'uuid' is a Universally Unique Identifier (UUID) standardized 128-bit format for a string ID used to uniquely identify information. It's used to uniquely identify your application's Bluetooth service.

 public ConnectThread(BluetoothDevice device) {
    // Use a temporary object that is later assigned to mmSocket,
    // because mmSocket is final
    BluetoothSocket tmp = null;
    mmDevice = device;

    // Get a BluetoothSocket to connect with the given BluetoothDevice
    try {
        // MY_UUID is the app's UUID string, also used by the server code
        tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
    } catch (IOException e) { }
    mmSocket = tmp;
}

I am not installing an app on both devices, so I don't get to set my own UUID, I want to use android's instead... but I can't find this in the docs anywhere.

Maybe I'm not approaching the problem correctly. Any help will be appreciated. Thanks in advance

Solution

You can get the UUID from the BluetoothDevice

    mmDevice = device;

    // Get a BluetoothSocket to connect with the given BluetoothDevice. This code below show how to do it and handle the case that the UUID from the device is not found and trying a default UUID.

    // Default UUID
    private UUID DEFAULT_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); 

    try {
        // Use the UUID of the device that discovered // TODO Maybe need extra device object
        if (mmDevice != null)
        {
            Log.i(TAG, "Device Name: " + mmDevice.getName());
            Log.i(TAG, "Device UUID: " + mmDevice.getUuids()[0].getUuid());
            tmp = device.createRfcommSocketToServiceRecord(mmDevice.getUuids()[0].getUuid());

        }
        else Log.d(TAG, "Device is null.");
    }
    catch (NullPointerException e)
    {
        Log.d(TAG, " UUID from device is null, Using Default UUID, Device name: " + device.getName());
        try {
            tmp = device.createRfcommSocketToServiceRecord(DEFAULT_UUID);
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }
    catch (IOException e) { }

Comments

[frankelot]

YOU! ARE! AWESOME! :D Thaaaaanks man, can't tell you how many hours I've wasted trying to figure this out.. I really appreciate it! :)

[Braunster]

With pleasure ive wasted to meny hours myself on this. You can check this github.com/itzikBraun/ArduinoCar its an app controlling and arduino via bluetooth there is two thread handling the connection maybe it would help you even more.

[frankelot]

It's so weird that android won't provide a method to pair two devices together!. (They only added one now, on API 19. When it seems something so basic and fundamental)

[frankelot]

Unfortunately, this only worked on SOME devices. :/ Not a definite solution.

[Braunster]

What was the problem maybe i can help.

[frankelot]

Well, your solution worked fine on some devices, but I got no answer whatsoever when tested against different android versions and phone models. I mean, in some cases, the devices just won't react to my connection attempt :(

[Braunster]

can you tell me which api did you use that caused you the problem? or to what device did you tried to connect?

[Siluni Upeksha]

I have same problem I want to connect to android 5.1.1 device but I was unable.can you please give me solution to connect any bluetooth device

[Greg Brown]

Checking for null explicitly is generally preferable to catching a NullPointerException.

[Manpreet Singh Dhillon]

in my case getuuids() returns null and device does not connect with default uuid. is there any work around please?

[luke cross]

where did you get this "00001101-0000-1000-8000-00805F9B34FB" string???????