For one-time, non-constant requests for a user's physical activity, use the Snapshot API:

// Remember to initialize your client as described in the Remarks section
Awareness.SnapshotApi.getDetectedActivity(client)
    .setResultCallback(new ResultCallback<DetectedActivityResult>() {
        @Override
        public void onResult(@NonNull DetectedActivityResult detectedActivityResult) {
            if (!detectedActivityResult.getStatus().isSuccess()) {
                Log.e(getClass().getSimpleName(), "Could not get the current activity.");
                return;
            }
            ActivityRecognitionResult result = detectedActivityResult
                .getActivityRecognitionResult();
            DetectedActivity probableActivity = result.getMostProbableActivity();
            Log.i(getClass().getSimpleName(), "Activity received : " + 
                probableActivity.toString());
        }
    });

// Remember to initialize your client as described in the Remarks section
Awareness.SnapshotApi.getHeadphoneState(client)
    .setResultCallback(new ResultCallback<HeadphoneStateResult>() {
        @Override
        public void onResult(@NonNull HeadphoneStateResult headphoneStateResult) {
            Log.i(TAG, "Headphone state connection state: " + 
                headphoneStateResult.getHeadphoneState()
                .getState() == HeadphoneState.PLUGGED_IN));
        }
    });

// Remember to intialize your client as described in the Remarks section
Awareness.SnapshotApi.getLocation(client)
    .setResultCallback(new ResultCallback<LocationResult>() {
        @Override
        public void onResult(@NonNull LocationResult locationResult) {
            Location location = locationResult.getLocation();
            Log.i(getClass().getSimpleName(), "Coordinates: "location.getLatitude() + "," + 
                location.getLongitude() + ", radius : " + location.getAccuracy());
        }
    });

// Remember to initialize your client as described in the Remarks section 
Awareness.SnapshotApi.getPlaces(client)
    .setResultCallback(new ResultCallback<PlacesResult>() {
        @Override
        public void onResult(@NonNull PlacesResult placesResult) {
            List<PlaceLikelihood> likelihoodList = placesResult.getPlaceLikelihoods();
            if (likelihoodList == null || likelihoodList.isEmpty()) {
                Log.e(getClass().getSimpleName(), "No likely places");
            }
        }
    });

As for getting the data in those places, here are some options:

Place place = placeLikelihood.getPlace();
String likelihood = placeLikelihood.getLikelihood();
Place place = likelihood.getPlace();
String placeName = place.getName();
String placeAddress = place.getAddress();
String placeCoords = place.getLatLng();
String locale = extractFromLocale(place.getLocale()));

// Remember to initialize your client as described in the Remarks section
Awareness.SnapshotApi.getWeather(client)
    .setResultCallback(new ResultCallback<WeatherResult>() {
        @Override
        public void onResult(@NonNull WeatherResult weatherResult) {
            Weather weather = weatherResult.getWeather();
            if (weather == null) {
                Log.e(getClass().getSimpleName(), "No weather received");
            } else {
                Log.i(getClass().getSimpleName(), "Temperature is " +
                        weather.getTemperature(Weather.CELSIUS) + ", feels like " +
                        weather.getFeelsLikeTemperature(Weather.CELSIUS) + 
                        ", humidity is " + weather.getHumidity());
            }
        }
    });

If you want to detect when your user starts or finishes an activity such as walking, running, or any other activity of the DetectedActivityFence class, you can create a fence for the activity that you want to detect, and get notified when your user starts/finishes this activity. By using a BroadcastReceiver, you will get an Intent with data that contains the activity:

// Your own action filter, like the ones used in the Manifest.
private static final String FENCE_RECEIVER_ACTION = BuildConfig.APPLICATION_ID +
    "FENCE_RECEIVER_ACTION";
private static final String FENCE_KEY = "walkingFenceKey";
private FenceReceiver mFenceReceiver;
private PendingIntent mPendingIntent;

// Make sure to initialize your client as described in the Remarks section.
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // etc.

    // The 0 is a standard Activity request code that can be changed to your needs.
    mPendingIntent = PendingIntent.getBroadcast(this, 0, 
        new Intent(FENCE_RECEIVER_ACTION), 0);
    registerReceiver(mFenceReceiver, new IntentFilter(FENCE_RECEIVER_ACTION));

    // Create the fence.
    AwarenessFence fence = DetectedActivityFence.during(DetectedActivityFence.WALKING);
    // Register the fence to receive callbacks.
    Awareness.FenceApi.updateFences(client, new FenceUpdateRequest.Builder()
        .addFence(FENCE_KEY, fence, mPendingIntent)
        .build())
        .setResultCallback(new ResultCallback<Status>() {
            @Override
            public void onResult(@NonNull Status status) {
                if (status.isSuccess()) {
                    Log.i(FENCE_KEY, "Successfully registered.");
                } else {
                    Log.e(FENCE_KEY, "Could not be registered: " + status);
                }
            }
        });
    }
}

Now you can receive the intent with a BroadcastReceiver to get callbacks when the user changes the activity:

public class FenceReceiver extends BroadcastReceiver {

    private static final String TAG = "FenceReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
        // Get the fence state
        FenceState fenceState = FenceState.extract(intent);

        switch (fenceState.getCurrentState()) {
            case FenceState.TRUE:
                Log.i(TAG, "User is walking");
                break;
            case FenceState.FALSE:
                Log.i(TAG, "User is not walking");
                break;
            case FenceState.UNKNOWN:
                Log.i(TAG, "User is doing something unknown");
                break;
        }
    }
}

If you want to detect when your user enters a specific location, you can create a fence for the specific location with a radius you want and be notified when your user enters or leaves the location.

// Your own action filter, like the ones used in the Manifest
private static final String FENCE_RECEIVER_ACTION = BuildConfig.APPLICATION_ID +
    "FENCE_RECEIVER_ACTION";
private static final String FENCE_KEY = "locationFenceKey";
private FenceReceiver mFenceReceiver;
private PendingIntent mPendingIntent;

// Make sure to initialize your client as described in the Remarks section
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // etc

    // The 0 is a standard Activity request code that can be changed for your needs
    mPendingIntent = PendingIntent.getBroadcast(this, 0, 
        new Intent(FENCE_RECEIVER_ACTION), 0);
    registerReceiver(mFenceReceiver, new IntentFilter(FENCE_RECEIVER_ACTION));

    // Create the fence
    AwarenessFence fence = LocationFence.entering(48.136334, 11.581660, 25);
    // Register the fence to receive callbacks.
    Awareness.FenceApi.updateFences(client, new FenceUpdateRequest.Builder()
        .addFence(FENCE_KEY, fence, mPendingIntent)
        .build())
        .setResultCallback(new ResultCallback<Status>() {
            @Override
            public void onResult(@NonNull Status status) {
                if (status.isSuccess()) {
                    Log.i(FENCE_KEY, "Successfully registered.");
                } else {
                    Log.e(FENCE_KEY, "Could not be registered: " + status);
                }
            }
        });
    }
}

Now create a BroadcastReciver to recive updates in user state:

public class FenceReceiver extends BroadcastReceiver {

    private static final String TAG = "FenceReceiver";

    @Override
    public void onReceive(Context context, Intent intent) {
        // Get the fence state
        FenceState fenceState = FenceState.extract(intent);

        switch (fenceState.getCurrentState()) {
            case FenceState.TRUE:
                Log.i(TAG, "User is in location");
                break;
            case FenceState.FALSE:
                Log.i(TAG, "User is not in location");
                break;
            case FenceState.UNKNOWN:
                Log.i(TAG, "User is doing something unknown");
                break;
        }
    }
}