You can get the Google Fit samples on GitHub.
AndroidWatchFace
This sample demonstrates how to create watch faces for Android Wear devices, and
includes a phone app and an Android Wear device app.
Get it on GitHub
BasicSensorsApi
This sample demonstrates how to register listeners to read raw sensor data from
a data source.
Get it on GitHub
BasicRecordingApi
This sample demonstrates how to request automated storage of sensor data by
creating subscriptions.
Get it on GitHub
BasicHistoryApi
This sample demonstartes how to read data from the user's fitness history.
Get it on GitHub
BasicHistorySessions
This sample demonstrates how to use sessions for fitness activities with the
fitness history.
Get it on GitHub
StepCounter
This sample demonstrates how to record steps and read them back.
Get it on GitHub