How to allow a device to be connected to with Bluetooth LE

I'm trying to connect a raspberry pi to my phone via Bluetooth LE. The raspberry pi scans for and connects to devices already, all I need to do it make my phone able to be connected to via the app I'm trying to develop for it. I have managed to make the phone advertise with the following code, but whenever I try to connect it always says "No data available". I can't seem to figure out how to get it to connect properly.

Here is my code:

    BluetoothAdapter bluetoothAdapter;
    String bluetoothAdapterString;

    final BluetoothManager bluetoothManager =
            (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
    bluetoothAdapter = bluetoothManager.getAdapter();
    bluetoothAdapterString = String.valueOf(bluetoothAdapter);

    BluetoothLeAdvertiser advertiser = BluetoothAdapter.getDefaultAdapter().getBluetoothLeAdvertiser();


    AdvertiseSettings settings = new AdvertiseSettings.Builder()
            .setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY)//*_LOW_POWER or BALANCED
            .setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_HIGH)
            .setConnectable(true)
            .build();


    ParcelUuid pUuid = new ParcelUuid(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));//this is a service UUID (according to https://stackoverflow.com/questions/11105891/how-do-i-find-the-proper-uuid)
    //this UUID might need to be changed
    AdvertiseData data = new AdvertiseData.Builder()
            .setIncludeDeviceName(true)
            .addServiceUuid(pUuid)
            .addServiceData(pUuid, "pleaseWork!".getBytes(StandardCharsets.UTF_8))//"UTF-8"
            .build();


    AdvertiseCallback advertisingCallback = new AdvertiseCallback() {
        @Override
        public void onStartSuccess(AdvertiseSettings settingsInEffect) {
            mainActivity.showMessage.show("bluetooth should be working");
            super.onStartSuccess(settingsInEffect);
        }

        @Override
        public void onStartFailure(int errorCode) {
            mainActivity.showMessage.show("advertising failure....");
            Log.e("BLE", "Advertising onStartFailure: " + errorCode);
            super.onStartFailure(errorCode);
        }
    };

    advertiser.startAdvertising(settings, data, advertisingCallback);

also, once the phone is connected to the raspberry pi, is there an easy way to transmit data between them?

I don't care about my current code, all I want in the end is for my phone to be discoverable and to be able to connect to the raspberry pi.

edit: clarity