Account authenticator and preference screen
<p>According to <a href="http://developer.android.com/reference/android/accounts/AbstractAccountAuthenticator.html" rel="nofollow">the doc</a> I can specify a <code>PreferenceScreen</code> to query information from the user (ie login and password) instead of manually adding a dummy activity, and deal with the actual authentication logic inside my <code>AbstractAccountAuthenticator.addAccount()</code> but actually the following code does nothing when you try to add an account (both from the regular android settings and via dev tools)</p>

<pre><code>&lt;account-authenticator xmlns:android="http://schemas.android.com/apk/res/android"
 android:accountType="com.example.auth"
 android:label="@string/auth_label"
 android:accountPreferences="@xml/auth_preferences" /&gt;
</code></pre>

<p>I mean, it should invoke an activity based on <code>auth_preferences</code> content, but nothing happens. I know I can create a separate activity like the SampleSync does, but I wonder what <code>android:accountPreferences</code> stays for</p>
