title: Radio Buttons in Menu using SharedPreferences
body: <p>Trying to have three radio buttons show up as menu items where the user picks only one and that choice is saved even if the app is closed.  The choice they pick will then be used to determine which layout fragment will be displayed when the app starts up.</p>
  
  <p>Don't really understand how to save the user choice in shared preferences as I have never used it before and new to coding.</p>
  
  <p>My Menu Layout is </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
  
  &lt;item android:id="@+id/settings"
      android:title="@string/settings"&gt;
      &lt;menu &gt;
          &lt;group android:id="@+id/startScreenGroup" android:checkableBehavior="single"&gt;
              &lt;item android:id="@+id/submenu0" android:title="Fragment 0" /&gt;
              &lt;item android:id="@+id/submenu1" android:title="Fragment 1" /&gt;
              &lt;item android:id="@+id/submenu2" android:title="Fragment 2" /&gt;
          &lt;/group&gt;
      &lt;/menu&gt;
  &lt;/item&gt;
  
  &lt;/menu&gt;
  </code></pre>