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Android bluetooth UUID connecting APP to ANDROID

Posted by: admin June 15, 2020 Leave a comment

Questions:

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

How to&Answers:

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) { }