How can I display a dialog box for making a choice before a CALL is processed in android?
<p>I would like to intercept outgoing calls and pass them to a VOIP application.  I see that the Google Voice application has a feature for displaying a question before each call is actually initiated.  It provides the user with the choice:</p>

<ul>
<li>Initiate call via Google Voice</li>
<li>Initiate call via standard call</li>
</ul>

<p>I would like a way to do something similar with my application (so that not all calls have to be routed through it).  At the moment, I can intercept CALL events via a BroadcastReceiver, however, these are not allowed to open dialogs (thus making it possible to display the choice).</p>

<p>What is the best way of achieving this goal?</p>
