How to update main activity to know that prefs are changed?
<p>I have</p>

<pre><code>SharedPreferences myPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
</code></pre>

<p>and </p>

<pre><code>myPreferences.getBoolean("checkbox", true)
</code></pre>

<p>So, how can my main activity know when user change preferences state?
For example if user don't wont to get notifications any more.
Thanks.</p>
