应用主题不随选择的偏好而改变？

这是我第一次涉足使用首选项来更改应用程序主题，并且我似乎无法使其正常工作。这里是我的代码：应用主题不随选择的偏好而改变？

MainActivity.Java onCreate方法

protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     SharedPreferences getPrefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext()); 
     String values = getPrefs.getString("list","1"); 
     if(values.contentEquals("1")){ 
      setTheme(R.style.Holo_Dark); 

     }else if(values.contentEquals("2")){ 
      setTheme(R.style.AppTheme); 

     } 

     setContentView(R.layout.activity_main); 

     mNavigationDrawerFragment = (NavigationDrawerFragment) 
       getFragmentManager().findFragmentById(R.id.navigation_drawer); 
     mTitle = getTitle(); 

     // Set up the drawer. 
     mNavigationDrawerFragment.setUp(
       R.id.navigation_drawer, 
       (DrawerLayout) findViewById(R.id.drawer_layout)); 

     TextView medEntry = (TextView)findViewById(R.id.med_name); 

     /* medEntry.setOnFocusListener(new FocusListner(){ 

     }); */ 

    }

Prefs.Java：

public class Prefs extends PreferenceActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState){ 



     super.onCreate(savedInstanceState); 
     addPreferencesFromResource(R.xml.prefs); 

    } 
}

array.xml的首选项：

<?xml version="1.0" encoding="utf-8"?> 
<resources> 
    <string-array name="list"> 

     <item>Dark</item> 
     <item>Light</item> 
    </string-array> 
    <string-array name="lValues"> 
     <item>1</item> 
     <item>2</item> 
    </string-array> 
</resources>

styles.xml：

<resources> 

    <!-- Base application theme. --> 
    <style name="AppTheme" parent="android:Theme.Holo.Light.DarkActionBar"> 
     <!-- Customize your theme here. --> 

    </style> 
    <style name="Holo_Dark" parent="android:Theme.Holo"> 

    </style> 

</resources>

和我的清单：

<application 
     android:allowBackup="true" 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     > 
     <activity 
      android:name=".MainActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 

     <activity 
      android:name=".Prefs" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.PREFS" /> 

       <category android:name="android.intent.category.DEFAULT" /> 
      </intent-filter> 
     </activity> 
    </application>

来源

2014-10-18 Michael Garber