服务从活动中被调用，但在logcat中什么都没有得到？

Question

This is kinda a repost and I'm sorry for that, but the last time I posted it I thought I got it down but apparently not. When I tried to call the Service I use to get this error Caused by: java.lang.IllegalStateException: GoogleApiClient is not connected yet. Because I was trying to call LocationServices before GoogleApiClient was even connected. So after changing the code up a bit I wasn't getting the error anymore, in fact I wasn't getting anything in logcat anymore. This is how I start my Service from SearchActivity.class:

SearchActivity.class

 button = (Button)findViewById(R.id.buttonPressed);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startService(new Intent(getBaseContext(), LocationService.class));

        }
    });

This is the Service:

LocationService.class

public class LocationService extends Service implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener, LocationListener {

    // LogCat tag
    private static final String TAG = LocationService.class.getSimpleName();

    private final static int PLAY_SERVICES_RESOLUTION_REQUEST = 1000;

    private Location mLastLocation;

    // Google client to interact with Google API
    private GoogleApiClient mGoogleApiClient;

    // boolean flag to toggle periodic location updates
    private boolean mRequestingLocationUpdates = false;

    private LocationRequest mLocationRequest;

    // Location updates intervals in sec
    private static int UPDATE_INTERVAL = 10000; // 10 sec
    private static int FATEST_INTERVAL = 5000; // 5 sec
    private static int DISPLACEMENT = 10; // 10 meters


    @Override
    public void onCreate() {
        super.onCreate();

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API).build();


    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        if (mGoogleApiClient != null) {
            if(mGoogleApiClient.isConnected()) {
                if (mLocationRequest != null) {
                    togglePeriodicLocationUpdates();
                }
            }
        }



        return START_NOT_STICKY;
    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    protected void createLocationRequest() {
        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(UPDATE_INTERVAL);
        mLocationRequest.setFastestInterval(FATEST_INTERVAL);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        mLocationRequest.setSmallestDisplacement(DISPLACEMENT);
    }

    private void togglePeriodicLocationUpdates() {
        mGoogleApiClient.connect();
        if(mGoogleApiClient.isConnected()) {
            if (!mRequestingLocationUpdates) {

                mRequestingLocationUpdates = true;

                startLocationUpdates();

                Log.d(TAG, "Periodic location updates started!");

            } else {

                mRequestingLocationUpdates = false;

                // Stopping the location updates
                stopLocationUpdates();

                Log.d(TAG, "Periodic location updates stopped!");
            }
        }
    }

    protected void stopLocationUpdates() {
        LocationServices.FusedLocationApi.removeLocationUpdates(
                mGoogleApiClient, this);
    }

    protected void startLocationUpdates() {
        mGoogleApiClient.connect();
        if(mGoogleApiClient.isConnected()) {
            LocationServices.FusedLocationApi.requestLocationUpdates(
                    mGoogleApiClient, mLocationRequest, this);
        }
    }

    @Override
    public void onConnected(Bundle arg0) {
        createLocationRequest();
    }

    @Override
    public void onConnectionSuspended(int arg0) {
        mGoogleApiClient.connect();
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {
        Log.i(TAG, "Connection failed: ConnectionResult.getErrorCode() = "
                + result.getErrorCode());
    }

@Override
public void onLocationChanged(Location location) {
    // Assign the new location
    mLastLocation = location;

    Toast.makeText(getApplicationContext(), "Location changed!",
            Toast.LENGTH_SHORT).show();
}

@Override
public boolean stopService(Intent name) {
    return super.stopService(name);
}

AndroidManifest.xml

    </activity>
    <service android:name=".LocationService">
    </service>

Edit:

Well I figured how to get it working. But now I'm facing the problem of having to click the button 2 times before it would start normally. Only had to change the onStartCommand() a bit.

 @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        if (mGoogleApiClient != null) {
            mGoogleApiClient.connect();
            if(mGoogleApiClient.isConnected()) {

                if (mLocationRequest != null) {

                    togglePeriodicLocationUpdates();
                }
            }
        }



        return START_NOT_STICKY;
    }

Answer 1

You should read the documentation on GoogleApiClient, particularly (for the question at hand) the connect() method . I've highlighted the relevant portion:

Connects the client to Google Play services. This method returns immediately, and connects to the service in the background. If the connection is successful, onConnected(Bundle) is called and enqueued items are executed. On a failure, onConnectionFailed(ConnectionResult) is called.

If the client is already connected or connecting, this method does nothing.

So, this is what currently happens with your code:

1. You click the button to launch the service.
2. You create the GoogleApiClient in onCreate().
3. You call connect() in onStartCommand which returns immediately while connection goes on in the background.
4. You check isConnected(), however, since connection is still going on, you do nothing and return from onStartCommand.
5. Later, you click the button the launch the service again.
6. As it has already been created, it goes directly to onStartCommand.
7. By this point, the GoogleApiClient has connected, so everything else works as expected.

What you should do is implement onConnected(). From there, call togglePeriodicLocationUpdates() instead of doing that in onStartCommand(). This will accomplish what you want:

1. Click button to launch service.
2. Service creates GoogleApiClient in onCreate().
3. Service initiates connection in onStartCommand().
4. Sometime in the future, the connection is established and service calls togglePeriodicLocationUpdates() from onConnected().