Professional Android Sensor Programming

Chapter 3

Tracking Device Movement

What's in this chapter?

Using the Android location service to continuously track device location

Using the Google Maps library to plot location data on a map

Using broadcast receivers to track location in the background

Considering effects on battery life

As an introduction to the Android location service, Chapter 2 discussed how to get the current location of a device. This chapter showcases additional functionality and presents an example app that tracks the location of a device as it moves. The app built in this chapter demonstrates how to receive the device's current location, persist that location in a database, and plot the path traveled — all the persisted locations — on a map using the Google Maps external library for Android.

With the additional functionality comes additional complexity. Continuously tracking device location data implies keeping more device hardware (such as Wi-Fi radio or GPS radio) active, which can adversely affect battery life. Also, the app needs to handle cases where it receives incorrect location data, as well as cases where one or all of the location providers are not available.

The example app for this chapter consists of three Android application components: an activity to display both the current location and previous locations, a broadcast receiver that receives location data in the background and stores the new locations in a database, and another broadcast receiver that receives location updates only when ...