Can't send message from Android Wear to host device

Question

I'm writing a simple Android application and I need to send a message from my Wear device to my mobile phone using MessageApi. Ultimately, I want to be able to send a message from my wear to the phone for it to then send a message back with the same node.

To start things off, I just want to click a button on my Wear app that will generate a toast in my mobile app. I'm testing this using an Android Wear emulator and an actual Android phone.

My Android mobile app has a separate ListenerService class;

public class ListenerService extends WearableListenerService {

    String nodeId;

    @Override
    public void onMessageReceived(MessageEvent messageEvent) {
        nodeId = messageEvent.getSourceNodeId();
        showToast(messageEvent.getPath());
    }

    private void showToast(String message) {
        Toast.makeText(this, message, Toast.LENGTH_LONG).show();
    }
}

And I am initalizing this in my manifest:

<service
  android:name=".ListenerService" >
    <intent-filter>
       <action android:name="com.google.android.gms.wearable.BIND_LISTENER" />
    </intent-filter>
</service>

In my Wear MainActivity.java;

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initApi();

        final WatchViewStub stub = (WatchViewStub) findViewById(R.id.watch_view_stub);
        stub.setOnLayoutInflatedListener(new WatchViewStub.OnLayoutInflatedListener() {
            @Override
            public void onLayoutInflated(WatchViewStub stub) {
                setupWidgets();
            }
        });
    }

    /**
     * Initializes the GoogleApiClient and gets the Node ID of the connected device.
     */
    private void initApi() {
        client = getGoogleApiClient(this);
        retrieveDeviceNode();
    }

    /**
     * Sets up the button for handling click events.
     */
    private void setupWidgets() {
        findViewById(R.id.btn_toast).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                sendToast();
            }
        });
    }

    /**
     * Returns a GoogleApiClient that can access the Wear API.
     * @param context
     * @return A GoogleApiClient that can make calls to the Wear API
     */
    private GoogleApiClient getGoogleApiClient(Context context) {
        return new GoogleApiClient.Builder(context)
                .addApi(Wearable.API)
                .build();
    }

    /**
     * Connects to the GoogleApiClient and retrieves the connected device's Node ID. If there are
     * multiple connected devices, the first Node ID is returned.
     */
    private void retrieveDeviceNode() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                client.blockingConnect(CONNECTION_TIME_OUT_MS, TimeUnit.MILLISECONDS);
                NodeApi.GetConnectedNodesResult result =
                        Wearable.NodeApi.getConnectedNodes(client).await();
                List<Node> nodes = result.getNodes();
                if (nodes.size() > 0) {
                    nodeId = nodes.get(0).getId();
                }
                client.disconnect();
            }
        }).start();
    }

    /**
     * Sends a message to the connected mobile device, telling it to show a Toast.
     */
    private void sendToast() {
        if (nodeId != null) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    client.blockingConnect(CONNECTION_TIME_OUT_MS, TimeUnit.MILLISECONDS);
                    Wearable.MessageApi.sendMessage(client, nodeId, MESSAGE, null);
                    client.disconnect();
                }
            }).start();
        }
    }
}

When debugging, nodeId is always null and hence the run() command is never run within the sendToast() function. However when I insert a breakpoint on Wearable.NodeApi.getConnectedNodes(client).await()in the retrieveDeviceNode(), my app just freezes and doesn't seem to be able to connect to any node.

Is there something I'm missing or doing wrong?