public void sendGenericOnOffGet() {
        if (!checkConnectivity(mContainer)) return;
        final Element element = mViewModel.getSelectedElement().getValue();
        if (element != null) {
            final MeshModel model = mViewModel.getSelectedModel().getValue();
            if (model != null) {
                if (!model.getBoundAppKeyIndexes().isEmpty()) {
                    final int appKeyIndex = model.getBoundAppKeyIndexes().get(0);
                    final ApplicationKey appKey = mViewModel.getNetworkLiveData().getMeshNetwork().getAppKey(appKeyIndex);

                    final int address = element.getElementAddress();
                    Log.v(TAG, "Sending message to element's unicast address: " + MeshAddress.formatAddress(address, true));

                    final GenericOnOffGet genericOnOffSet = new GenericOnOffGet(appKey);
                    sendAcknowledgedMessage(address, genericOnOffSet);
                } else {
                    mViewModel.displaySnackBar(this, mContainer, getString(R.string.error_no_app_keys_bound), Snackbar.LENGTH_LONG);
                }
            }
        }
    }
Send generic on off get to mesh node
app/src/main/java/no/nordicsemi/android/nrfmesh/node/GenericOnOffServerActivity.java