xref: /frameworks/base/docs/html/guide/topics/location/index.jd

page.title=Location and Maps
@jd:body

<div id="qv-wrapper">
<div id="qv">

  <h2>Quickview</h2>
  <ul>
    <li>Android provides a location framework that your application can use to determine the
device's location and bearing and register for updates</li>
    <li>A Google Maps external library is available that lets you display and manage Maps data</li>
  </ul>

  <h2>Topics</h2>
  <ol>
    <li><a href="{@docRoot}guide/topics/location/obtaining-user-location.html">Obtaining User
Location</a></li>
  </ol>
  
  <h2>See Also</h2>
  <ol>
    <li><a
href="http://code.google.com/android/add-ons/google-apis/maps-overview.html">Google
Maps External Library &raquo;</a></li>
  </ol>
</div>
</div>

<p>Location and maps-based applications are compelling for mobile device users. You
can build these capabilities into your applications using the classes of the {@link
android.location} package and the Google Maps external library. The sections below provide details.
</p>

<h2 id="location">Location Services</h2>

<p>Android gives your applications access to the location services supported by
the device through the classes in the {@code android.location} package. The
central component of the location framework is the 
{@link android.location.LocationManager} system service, which provides APIs to
determine location and bearing of the underlying device (if available). </p>

<p>As with other system services, you do not instantiate a {@link android.location.LocationManager}
directly. Rather, you request an instance from the system by calling
{@link android.content.Context#getSystemService(String)
getSystemService(Context.LOCATION_SERVICE)}. The method returns a handle to a new {@link
android.location.LocationManager} instance.</p>

<p>Once your application has a {@link android.location.LocationManager}, your application
is able to do three things:</p>

<ul>
    <li>Query for the list of all {@link android.location.LocationProvider}s for the last known
user location.</li>
    <li>Register/unregister for periodic updates of the user's current location from a
    location provider (specified either by criteria or name).</li>
    <li>Register/unregister for a given {@link android.content.Intent} to be fired if the device
comes within a given proximity (specified by radius in meters) of a given lat/long.</li>
</ul>

<p>For more information, read the guide to <a
href="{@docRoot}guide/topics/location/obtaining-user-location.html">Obtaining User
Location</a>.</p>


<h2 id="maps">Google Maps External Library</h2>

<p>To make it easier for you to add powerful mapping capabilities to your
application, Google provides a Maps external library that includes the
com.google.android.maps package. The classes of the com.google.android.maps
package offer built-in downloading, rendering, and caching of Maps tiles, as
well as a variety of display options and controls. </p>

<p>The key class in the Maps package is
<code>com.google.android.maps.MapView</code>, a subclass of 
{@link android.view.ViewGroup ViewGroup}. A MapView displays a map with data obtained
from the Google Maps service. When the MapView has focus, it will capture
keypresses and touch gestures to pan and zoom the map automatically, including
handling network requests for additional maps tiles. It also provides all of the
UI elements necessary for users to control the map. Your application can also
use MapView class methods to control the MapView programmatically and draw a
number of Overlay types on top of the map. </p>

<p>In general, the MapView class provides a wrapper around the Google Maps API
that lets your application manipulate Google Maps data through class methods,
and it lets you work with Maps data as you would other types of Views.</p>

<p>The Maps external library is not part of the standard Android library, so it
may not be present on some compliant Android-powered devices. Similarly, the
Maps external library is not included in the standard Android library provided
in the SDK. So that you can develop using the classes of the
com.google.android.maps package, the Maps external library is made available to
you as part of the Google APIs add-on for the Android SDK. </p>

<p>To learn more about the Maps external library and how to download and use the
Google APIs add-on, visit</p>

<p style="margin-left:2em;"><a
href="http://code.google.com/android/add-ons/google-apis">http://code.google.com/android/add-ons/google-apis</a></p>

<p>For your convenience, the Google APIs add-on is also available as a downloadable component from
the Android SDK and AVD Manager (see <a href="{@docRoot}sdk/adding-components.html">Adding SDK
Components</a>).</p>

<p class="note"><strong>Note:</strong> In order to display Google Maps data in a
MapView, you must register with the Google Maps service and obtain a Maps API
Key. For information about how to get a Maps API Key, see <a
href="http://code.google.com/android/add-ons/google-apis/mapkey.html">Obtaining
a Maps API Key</a>.</p>