page.title=Desktop Head Unit
page.tags="auto", "car", "testing","dhu"
@jd:body


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

    <h2>In this document</h2>
    <ol>
      <li><a href="#launching-dhu">Launching the DHU</a></li>
      <li><a href="#dhu-commands">Issuing DHU Commands</a></li>
    </ol>

  <h2>See also</h2>
  <ol>
    <li><a href="{@docRoot}training/auto/start/index.html#test-it-dhu">Run and Test Auto Apps</a></li>
  </ol>

</div>
</div>


<p>The Desktop Head Unit (DHU) enables your development machine to emulate an Android Auto
head unit, so you can easily run and test Android Auto apps. The DHU runs on
Windows, Mac, and Linux hosts and replaces previous Android Auto simulators,
such as the Android Media Browser and Messaging
simulators.</p>

<p class="note"><strong>Note:</strong> For other information about testing Auto apps, see the
training lesson
<a href="{@docRoot}training/auto/start/index.html#test-it-dhu">Run and Test Auto Apps</a>.  </p>


<h2 id="launching-dhu">Launching the DHU</h2>

<p>
  To launch the DHU, run the <code>desktop-head-unit.exe</code> (on Windows)
  or <code>desktop-head-unit</code> (on Mac or Linux) command, as described in
  <a href="{@docRoot}training/auto/start/index.html#connecting-dhu">Connecting
  the DHU to your mobile device</a>.
</p>

<p>
  By default, the DHU emulates the most common form of Android Auto-compatible
  head unit, which uses a touch screen user interface. You can simulate user
  touches by clicking the DHU with a mouse. To emulate head units which use
  a rotary controller for input, you can use the <code>-i controller</code> flag,
  as in this example:
</p>

<pre class="no-pretty-print">$ ./desktop-head-unit -i controller</pre>

<p>
  When the DHU is in rotary-controller mode you can simulate controller
  operations by using keyboard shortcuts, as described in <a href=
  "#cmd-bindings">DHU commands and key bindings</a>. If the DHU is in rotary
  controller mode, it ignores mouse clicks; you must operate Android Auto with
  the simulated rotary controller operations.
</p>

<h2 id="dhu-commands">Issuing DHU Commands</h2>

<p>
  DHU commands allow you to test your app with Android Auto features, such as
  playing voice input or switching between night and day display mode. You can issue commands to
  the DHU by running commands from the terminal window where you launched DHU.
  You can also issue commands by selecting the DHU window and
  using keyboard shortcuts. The DHU commands
  and key bindings for all controls are listed in <a href="#cmd-bindings">DHU
  commands and key bindings</a>.
</p>


<h3 id="day-night">Switching between day and night mode</h3>

<p>
  Android Auto supports different color schemes for day and night. You should test your app in both
  day and night mode. You can switch between night and day mode in either of the
  following ways:
</p>

<ul>
  <li>Run the command <code>daynight</code> in the terminal where you launched the DHU.
  </li>

  <li>Select the DHU window and press the <strong>N</strong> key.
  </li>
</ul>

<h3>Microphone testing</h3>

<p>The DHU supports using a microphone for voice input. You can also instruct the DHU to treat
a pre-recorded voice track as input, as if the DHU had heard the track through the microphone.</p>

<p>To use a pre-recorded sound file as input, enter this command: </p>
<pre class="no-pretty-print">
$ mic play &lt;sound_file_path&gt;/&lt;sound_file&gt;.wav
</pre>

<p>For your convenience, we have provided the following sound files for common
voice commands. These sound files are installed in the
<code>&lt;sdk&gt;/extras/google/auto/voice/</code> directory.</p>

<dl>
  <dt>
    <code>exitnav.wav</code>
  </dt>

  <dd>
    "Exit navigation."
  </dd>

  <dt>
    <code>navgoogle.wav</code>
  </dt>

  <dd>
    "Navigate to 1600 Amphitheatre Parkway, Mountain View."
  </dd>

  <dt>
    <code>navsoh.wav</code>
  </dt>

  <dd>
    "Navigate to Sydney Opera House."
  </dd>

  <dt>
    <code>nextturn.wav</code>
  </dt>

  <dd>
    "When is my next turn?"
  </dd>

  <dt>
    <code>showalternateroute.wav</code>
  </dt>

  <dd>
    "Show alternate routes.""
  </dd>

  <dt>
    <code>howlong.wav</code>
  </dt>

  <dd>
    "How long until I get there?"
  </dd>

  <dt>
    <code>navhome.wav</code>
  </dt>

  <dd>
    "Navigate to home."
  </dd>

  <dt>
    <code>navwork.wav</code>
  </dt>

  <dd>
    "Navigate to work.""
  </dd>

  <dt>
    <code>pause.wav</code>
  </dt>

  <dd>
    "Pause music."
  </dd>

  <dt>
    <code>showtraffic.wav</code>
  </dt>

  <dd>
    "Show traffic."
  </dd>
</dl>
<h3 id="cmd-bindings">DHU commands and key bindings</h3>

<p>The DHU supports the following commands.</p>

<p class="table-caption" id="table-commands"><strong>Table 1.</strong> Commands and key bindings</p>
<table>
<tr>
  <th>Category</th>
  <th>Command</th>
  <th>Subcommand</th>
  <th>Argument(s)</th>
  <th>Keyboard Shortcut(s)</th>
  <th>Description</th>
</tr>

<!--system-->

<tr>
<td rowspan="4">System</td>
<td>help</td>
<td></td>
<td>[command]</td>
<td></td>
<td>Shows the full command set. Specifying a command name (for example, <code>help day</code>)
  causes the system to show help for that command.</td>
</tr>

<tr>

<td>quit</td>
<td></td>
<td></td>
<td>Alt+q</td>
<td>Quits the head unit.</td>
</tr>

<tr>

<td>sleep</td>
<td></td>
<td>[seconds]</td>
<td></td>
<td>Sleeps for one second. Specifying an argument (for example, <code>sleep 30</code>) causes the
system to sleep the specified number of seconds. This command
is useful if you are writing scripts for the DHU. (You can run a script by using I/O redirection
from the command line: <code>./desktop-head-unit &lt; script.txt</code> loads commands from the
file <code>script.txt</code>.)</td>
</tr>

<tr>

<td>screenshot</td>
<td></td>
<td>filename.png</td>
<td></td>
<td>Saves a screenshot to <code>filename.png</code>.</td>
</tr>


<!--microphone-->

<tr>
<td rowspan="3">Microphone</td>
<td rowspan="3">mic</td>
<td>begin</td>
<td></td>
<td>m </td>
<td>Activates the microphone (equivalent to clicking the steering wheel's microphone button) and
waits for input from the computer microphone.</td>
</tr>

<tr>


<td>play</td>
<td>filename.wav</td>
<td></td>
<td>Causes the DHU to treat <code>filename.wav</code> as voice input, as if it had heard that sound
  through the microphone. You do not hear the sound file being played, but you do hear
  the response from Android Auto.</td>
</tr>

<tr>


<td>repeat</td>
<td></td>
<td></td>
<td>Repeats the last <code>mic play</code> command, as if you had called <code>mic play</code>
  again with the same sound file parameter.</td>
</tr>

<!--Input-->

<tr>
<td rowspan="7">Input</td>
<td rowspan="6">dpad</td>
<td>up <br> down <br> left <br> right</td>
<td></td>
<td>Arrow keys</td>
<td>Simulates moving the rotary controller.</td>
</tr>

<tr>


<td>soft left <br> soft right</td>
<td></td>
<td>Shift+Arrow keys</td>
<td>Simulates pressing the side buttons available on some rotary controllers.</td>
</tr>

<tr>


<td>click</td>
<td></td>
<td>Return</td>
<td>Simulates pressing the rotary controller.</td>
</tr>

<tr>


<td>back</td>
<td></td>
<td>Backspace</td>
<td>Simulates pressing the <strong>back</strong> button available below some rotary
  controllers.</td>
</tr>

<tr>


<td>rotate left <br> rotate right</td>
<td></td>
<td>1 <br> 2</td>
<td>Simulates rotating the rotary controller left (counter-clockwise) or right (clockwise).</td>
</tr>

<tr>


<td>flick left <br> flick right</td>
<td></td>
<td>Shift+1 <br> Shift+2</td>
<td>Simulates a fast spin of the rotary controller to the left (counter-clockwise) or right
  (clockwise).</td>
</tr>

<tr>

<td>tap</td>
<td></td>
<td>x y</td>
<td></td>
<td>Simulates a touch event at the specified coordinates. For example, <code>tap 50 100</code></td>
</tr>


<!--Day/Night-->

<tr>
<td rowspan="3">Day/Night</td>
<td>day</td>
<td></td>
<td></td>
<td>Shift+n</td>
<td>Activates day mode (high brightness, full color).</td>
</tr>

<tr>

<td>night</td>
<td></td>
<td> </td>
<td>Ctrl+n </td>
<td>Activates night mode (low brightness, high contrast).</td>
</tr>

<tr>

<td>daynight</td>
<td></td>
<td></td>
<td>n </td>
<td>Toggles current day/night mode.</td>
</tr>

</table>




<h2 id="auto-simulators">Media Browser and Messaging Simulators</h2>

<p class="caution"><strong>Important:</strong> Use of the Android Media Browser and Messaging
Simulators for testing Android Auto apps is deprecated. Instead, we recommend using the
Desktop Head Unit, which enables your development machine to act as if it were an Android Auto head
unit.</p>

<p>To get the simulators, open the
<a href="{@docRoot}tools/help/sdk-manager.html">SDK Manager</a> and download
them from <strong>Extras &gt; Android Auto API Simulators</strong>.</p>

<p>Before you begin testing, compile your app in your development environment.
Install your app and the Android simulator for the features you want to test
(that is, audio or messaging) on a physical or virtual device running Android
5.0 (API level 21) or higher. To check the version of Android on the device, go
to <strong>Settings &gt; About phone</strong> (or <strong>About tablet</strong>)
<strong>&gt; Android Version</strong>.</p>

<h3 id="testing-audio-apps">Testing audio apps</h3>
<p>To run and test audio apps:</p>

<ol>
<li>Install the Android Media Browser simulator
({@code &lt;sdk&gt;/extras/google/simulators/media-browser-simulator.apk}) on
the test device. You can do this using
the <a href="{@docRoot}tools/help/adb.html#move">adb</a> command line tool.</li>
<li>Enable <a href="{@docRoot}tools/device.html#developer-device-options">
developer options</a> on the test device.</li>
<li>Install your app on the test device.</li>
<li>Launch the Android Media Browser simulator to see how your audio app
appears in Auto. If your app does not appear, stop the simulator from
<strong>Settings &gt; Apps</strong> and restart it.</li>
</ol>


<h3 id="testing-messaging-apps">Testing messaging apps</h3>
<p>To run and test messaging apps:</p>

<ol>
<li>Install the Android Messaging simulator
  ({@code &lt;sdk&gt;/extras/google/simulators/messaging-simulator.apk})
on the test device. You can do this using the
<a href="{@docRoot}tools/help/adb.html#move">adb</a> command line tool.</li>
<li>Enable the simulator to read notifications posted on the system:
<ol type="a">
	<li>Enable <a href="{@docRoot}tools/device.html#developer-device-options">
developer options</a> on the test device.</li>
  <li>Click <strong>Settings &gt; Sounds &amp; Notifications &gt; Notification
    Access</strong> and check the box labeled
    <strong>Messaging Simulator</strong>.</li>
</ol>
<li>Install your app on the test device.</li>
<li>Launch the Android Messaging Simulator to see how your messaging app appears
in Auto. If your app does not appear, stop the simulator from
<strong>Settings &gt; Apps</strong> and restart it.</li>
</ol>