android - Can't get preference set with PreferenceActivity -

i have main activity:

public class home extends activity {     @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.home);         initializestyle();     }     private void initializestyle() {         sharedpreferences prefs = preferencemanager.getdefaultsharedpreferences(this);         string foobar = prefs.getstring("foobar", "hi");         log.i("myactivity", foobar);     } // ... } 

and preferenceactivity:

public class preferences extends preferenceactivity {     @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         addpreferencesfromresource(r.xml.preferences);     } } 

with xml:

<?xml version="1.0" encoding="utf-8"?> <preferencescreen   xmlns:android="http://schemas.android.com/apk/res/android"> <preferencecategory          android:key="preferences_font"         android:title="@string/preferences_font">     <edittextpreference             android:title="@string/preferences_font_size"             android:key="foobar"             android:defaultvalue="12">     </edittextpreference> </preferencecategory> </preferencescreen> 

log.i prints "hi", means preference doesn't exist or named badly.

any idea i've done wrong?

regards,

this might on track , having working preferences:

xml file: preferences.xml

<?xml version="1.0" encoding="utf-8"?> <preferencescreen xmlns:android="http://schemas.android.com/apk/res/android">     <preferencecategory android:title="preferences font">         <edittextpreference              android:title="select font size"              android:key="foobar"              android:summary="enter font size"             android:defaultvalue="12" />     </preferencecategory> </preferencescreen>  

java file 1: home.java

public class home extends activity {      public sharedpreferences prefs;      static public string fontpref; //you can make int or whatever need     static public string myvalue; //to store new pref value      /** called when activity first created. */     @override     public void oncreate(bundle savedinstancestate) {           setcontentview(r.layout.home);          initializestyle();     }       private void initializestyle() {        prefs = preferencemanager.getdefaultsharedpreferences(this);        fontpref = prefs.getstring("foobar", "hi"); //this doesn't change value        myvalue = "this test";        log.i("myactivity", foobar); //won't show change yet     } } 

java file 2: prefernce.java

import android.preference.preference; import android.preference.preferenceactivity; import android.preference.preferencemanager; //... , other imports  public class preferences extends preferenceactivity  implements onsharedpreferencechangelistener{      private sharedpreferences prefs;      @override     public void oncreate(bundle savedinstancestate) {          super.oncreate(savedinstancestate);         addpreferencesfromresource(r.xml.preferences);         //add other stuff here if need, if might have         //prefs use buttons , need set onclicklistener 1     }      @override     public void onsharedpreferencechanged(sharedpreferences sharedpref, string key) {         editor editor = sharedpref.edit();         if(key.equalsignorecase("foobar")){             home.fontpref = sharedpref.getstring("foobar", "some value");             editor.putstring("foobar", home.myvalue); //where ever or whatever new value          }          editor.commit();         log.i("prefsactivity", foobar); //should show change     } }  

hopefully may on right track. of course there many ways these things so, luck hope helps.