Let's take a look at how the Gradle build files are configured. The settings.gradle file in the root folder includes all the modules for this project. In this case, it's just one module, which is the Wearable module folder:

You will notice that there are two build.gradle files. One is at the project level and the other is inside the Wearable folder's module level.

The project's build.gradle file is empty because we don't have anything specific to the project build settings, whereas the build.gradle file in the Wearable module contains all the build configurations for this app:

Lines 20, 21, and 22 of the build.gradle file specifies the external build dependencies for this project. Line 20 includes the dependency for Google Play Services, which is an integral part of the Android Wear platform. Google Play Services is used heavily for data synchronization and communication between the Android phones and wearable devices. We'll be covering them in detail in later chapters...