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<p>Provides classes which allow applications to use Wi-Fi RTT (IEEE 802.11mc) to measure distance
    to supporting Access Points and peer devices.</p>
<p>The primary entry point to Wi-Fi RTT capabilities is the
    {@link android.net.wifi.rtt.WifiRttManager} class, which is acquired by calling
    {@link android.content.Context#getSystemService(String)
    Context.getSystemService(Context.WIFI_RTT_RANGING_SERVICE)}</p>

<p>Some APIs may require the following user permissions:</p>
<ul>
    <li>{@link android.Manifest.permission#ACCESS_WIFI_STATE}</li>
    <li>{@link android.Manifest.permission#CHANGE_WIFI_STATE}</li>
    <li>{@link android.Manifest.permission#ACCESS_FINE_LOCATION}</li>
</ul>
<p>Usage of the API is also gated by the device's Location Mode: whether it permits Wi-Fi based
location to be queried.</p>

<p class="note"><strong>Note:</strong> Not all Android-powered devices support Wi-Fi RTT
    functionality.
    If your application only works with Wi-Fi RTT (i.e. it should only be installed on devices which
    support Wi-Fi RTT), declare so with a <a
            href="{@docRoot}guide/topics/manifest/uses-feature-element.html">
        {@code <uses-feature>}</a>
    element in the manifest file:</p>
<pre>
&lt;manifest ...>
    &lt;uses-feature android:name="android.hardware.wifi.rtt" />
    ...
&lt;/manifest>
</pre>
<p>Alternatively, if your application does not require Wi-Fi RTT but can take advantage of it if
    available, you can perform
    the check at run-time in your code using {@link
    android.content.pm.PackageManager#hasSystemFeature(String)} with {@link
    android.content.pm.PackageManager#FEATURE_WIFI_RTT}:</p>
<pre>
    getPackageManager().hasSystemFeature(PackageManager.FEATURE_WIFI_RTT)
</pre>

<p>For an example of this functionality, see
<a href="{@docRoot}guide/topics/connectivity/wifi-rtt" class="external">Wi-Fi location: ranging
with RTT</a>.</p>
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