title: Easy way to build Android system app ? (Eclipse for example)
body: <p>Can somebody tell me if there is a simple way to build system apps for Android?</p>
  
  <p>Since ICS 4.0.3 is out and open source, severals alternative launchers start rolling out like <a href="http://forum.xda-developers.com/showthread.php?t=1410674" rel="nofollow noreferrer">Trebuchet</a> or <a href="http://forum.xda-developers.com/showthread.php?t=1389071" rel="nofollow noreferrer">Nova Launcher</a>. It's obviously based on the system launcher and I wonder how they did this.</p>
  
  <p>If you clone the launcher:</p>
  
  <pre><code>git clone https://android.googlesource.com/platform/packages/apps/Launcher2.git
  </code></pre>
  
  <p>and try to open it in Eclipse, it won't work because it use some classes and variable not present in the SDK, only present in the entire framework.</p>
  
  <p>Is there a way to build or get it and add it into Eclipse (like <code>android.jar</code> for the SDK) and build the Launcher using eclipse? If no, can somebody indicates me a good tutorial to do this usong command line?</p>