MainActivity.java

package com.ptrprograms.wearmessageapi;

import android.app.Activity;
import android.os.Bundle;
import android.view.WindowManager;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.wearable.MessageApi;
import com.google.android.gms.wearable.MessageEvent;
import com.google.android.gms.wearable.Wearable;

public class MainActivity extends Activity implements MessageApi.MessageListener, GoogleApiClient.ConnectionCallbacks {

    private static final String WEAR_MESSAGE_PATH = "/message";
    private GoogleApiClient mApiClient;
    private ArrayAdapter<String> mAdapter;

    private ListView mListView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mListView = (ListView) findViewById(R.id.list);

        mAdapter = new ArrayAdapter<String>( this, R.layout.list_item );
        mListView.setAdapter( mAdapter );

        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

        initGoogleApiClient();
    }

    private void initGoogleApiClient() {
        mApiClient = new GoogleApiClient.Builder( this )
                .addApi( Wearable.API )
                .addConnectionCallbacks( this )
                .build();

        if( mApiClient != null && !( mApiClient.isConnected() || mApiClient.isConnecting() ) )
            mApiClient.connect();
    }

    @Override
    protected void onResume() {
        super.onResume();
        if( mApiClient != null && !( mApiClient.isConnected() || mApiClient.isConnecting() ) )
            mApiClient.connect();
    }

    @Override
    protected void onStart() {
        super.onStart();
    }

    @Override
    public void onMessageReceived( final MessageEvent messageEvent ) {
        runOnUiThread( new Runnable() {
            @Override
            public void run() {
                if( messageEvent.getPath().equalsIgnoreCase( WEAR_MESSAGE_PATH ) ) {
                    mAdapter.add(new String(messageEvent.getData()));
                    mAdapter.notifyDataSetChanged();
                }
            }
        });
    }

    @Override
    public void onConnected(Bundle bundle) {
        Wearable.MessageApi.addListener( mApiClient, this );
    }

    @Override
    protected void onStop() {
        if ( mApiClient != null ) {
            Wearable.MessageApi.removeListener( mApiClient, this );
            if ( mApiClient.isConnected() ) {
                mApiClient.disconnect();
            }
        }
        super.onStop();
    }

    @Override
    protected void onDestroy() {
        if( mApiClient != null )
            mApiClient.unregisterConnectionCallbacks( this );
        super.onDestroy();
    }

    @Override
    public void onConnectionSuspended(int i) {

    }
}