To help you started, you can see this site for the introduction.
Android Wear is a lightweight platform that connects to the wearer’s
body and provides the right information at the right time. Wear makes
it easy for users to be more connected to both the online and real
worlds by making important information available at a glance and
allowing users to complete tasks quickly.
For further reference you can also explore the Google Fit documentation.
From there you will learn about the features that you may be looking.
The Google Fit APIs for Android are part of Google Play services and
are supported in Android 2.3 (API level 9) and higher. Google Fit on
Android consists of these APIs:
- The Sensors API provides access to raw sensor data streams from sensors available on the Android device and from sensors available in
companion devices, such as wearables.
- The Recording API provides automated storage of fitness data using subscriptions. Google Fit stores fitness data of the specified types
in the background and persists app subscriptions.
- The History API provides access to the fitness history and lets apps perform bulk operations, like inserting, deleting, and reading
fitness data. Apps can also import batch data into Google Fit.
- The Sessions API provides functionality to store fitness data with session metadata. Sessions represent a time interval during which
users perform a fitness activity.
- The Bluetooth Low Energy API provides access to Bluetooth Low Energy sensors in Google Fit. This API enables your app to look for
available BLE devices and to store data from them in the fitness
store.
- The Config API provides custom data types and additional settings for Google Fit. For more information, see Custom Data Types and
Disconnect from Google Fit.
Google Fit includes support for sensors on the mobile device and
Bluetooth Low Energy sensors paired with the device. Google Fit lets
developers implement support for other sensors and expose them as
software sensors in Android apps. Sensors supported by Google Fit are
available to Android apps as data source objects.
Use the Sensor API to count the steps in Android Wear using the Step Counter Sensor.
private SensorManager mSensorManager;
private Sensor mSensor;
...
mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER);
For Tizen, you can check the design principle that was provided in their site.