Examples for Java Client Library for Google Fit REST API (not Android API!)

Question

I want to write a java program using the Google Fit REST API. (It's not an Android app, so I can't use the Android API.)

It seems like there is a Java Client library for the REST API - so I was thinking this would be easy.

However, I can't find any samples/examples that explain how to use the client library (just the javadoc).

I found examples about how to use the Android API - e.g. this. But it's completely different, so no use.

For other Google APIs that I have used, the Client Library comes with examples... not so in this case.

Any ideas please? Thanks.

Answer 1

By piecing together some information from the javadoc, the REST API documentation, and by using some of my own examples from using other Google API Java Client Libraries, I have been able to make it work more or less... Here are some code snippets:

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.services.fitness.Fitness;
import com.google.api.services.fitness.model.*;

Get a GoogleCredential - this library is well documented...

GoogleCredential credential = new GoogleCredential.Builder()
                                     .setTransport(HTTP_TRANSPORT)
                                     .setJsonFactory(JSON_FACTORY)
                                     ...
                                     .build();

Create the service that is the basis for all the calls, using credential just created...

Fitness service = new Fitness.Builder(
                           HTTP_TRANSPORT, 
                           JSON_FACTORY, 
                           credential)
                           .setApplicationName(APPLICATION_NAME)
                           .build();

Create one or more data sources for your application / device

DataSource content = new DataSource()
                            .setApplication(YOUR_APPLICATION)
                            .setType(DATA_SOURCE_RAW)
                            .setName(name)
                            .setDataType(dataType);

Fitness.Users.DataSources.Create request = 
         service.users().dataSources().create("me", content);

DataSource ds = request.execute();

This is an example of a dataType that you need to use when you create your own DataSource... This is using a standard, public metric (in this case steps) that Google exposes... see this.

private static final String DT_STEPS = "com.google.step_count.delta";
private static final DataTypeField FIELD_STEPS = new 
        DataTypeField().setName("steps").setFormat(FORMAT_INTEGER);
private static final List<DataTypeField> STEPS_FIELDS = Arrays.asList(
                                                        FIELD_STEPS);
public static final DataType DATA_TYPE_STEPS = 
                            new DataType()
                                .setName(DT_STEPS)
                                .setField(STEPS_FIELDS);

Now create the actual data points, of that DataType, using that DataSource - in a DataSet...

    Value value = new Value().setIntVal(Integer.valueOf(steps));
    List<Value> values = Arrays.asList(value);

    DataPoint point = new DataPoint()
                            .setValue(values)
                            .setDataTypeName(DT_STEPS)
                            .setStartTimeNanos(startNS)
                            .setEndTimeNanos(endNS);

    List<DataPoint> dataPoints = Arrays.asList(point);

    String datasetId = startNS + "-" endNS;

    Dataset content = new Dataset()
                            .setDataSourceId(dataSourceId)
                            .setPoint(dataPoints)
                            .setMinStartTimeNs(startNS)
                            .setMaxEndTimeNs(endNS);

    Fitness.Users.DataSources.Datasets.Patch request = 
           service.users().dataSources().datasets().patch(
                "me", 
                dataSourceId, 
                datasetId, 
                content);

    Dataset ds = request.execute();

You still need to create a Session and a Segment Activity DataSet... but those follow similar structures.