not working with Preference Headers

I tried to build my preferences with preference headers using this lib, but I'm getting the following error when clicking on a header:

    2513-2513/org.testing.preferencefragment_test E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: org.testing.preferencefragment_test, PID: 2513
    java.lang.RuntimeException: Unable to start activity ComponentInfo{org.testing.preferencefragment_test/org.testing.preferencefragment_test.ApplicationPreferencesActivity}: android.app.Fragment$InstantiationException: Trying to instantiate a class org.testing.preferencefragment_test.ApplicationPreferencesActivity$SettingsFragmentTest that is not a Fragment
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: android.app.Fragment$InstantiationException: Trying to instantiate a class org.testing.preferencefragment_test.ApplicationPreferencesActivity$SettingsFragmentTest that is not a Fragment
            at android.app.Fragment.instantiate(Fragment.java:585)
            at android.preference.PreferenceActivity.switchToHeaderInner(PreferenceActivity.java:1183)
            at android.preference.PreferenceActivity.switchToHeader(PreferenceActivity.java:1199)
            at android.preference.PreferenceActivity.onCreate(PreferenceActivity.java:545)
            at android.app.Activity.performCreate(Activity.java:5231)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.ClassCastException
            at android.app.Fragment.instantiate(Fragment.java:585)
            at android.preference.PreferenceActivity.switchToHeaderInner(PreferenceActivity.java:1183)
            at android.preference.PreferenceActivity.switchToHeader(PreferenceActivity.java:1199)
            at android.preference.PreferenceActivity.onCreate(PreferenceActivity.java:545)
            at android.app.Activity.performCreate(Activity.java:5231)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)

I created a test-project at: https://github.com/agrajaghh/PreferenceFragment-Test following the guidlines at https://developer.android.com/guide/topics/ui/settings.html#PreferenceHeaders

The PreferenceActivity looks like this:

package org.testing.preferencefragment_test;

import android.os.Bundle;
import android.preference.PreferenceActivity;
// Not working:
import android.support.v4.preference.PreferenceFragment;
// working:
//import android.preference.PreferenceFragment;

import java.util.List;

public class ApplicationPreferencesActivity extends PreferenceActivity {
  @Override
  public void onBuildHeaders(List<Header> target) {
    loadHeadersFromResource(R.xml.preference_headers, target);
  }

  @Override
  protected boolean isValidFragment (String fragmentName)
  {
    return (SettingsFragmentTest.class.getName().equals(fragmentName));
  }

  public static class SettingsFragmentTest extends PreferenceFragment {
    @Override
    public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      addPreferencesFromResource(R.xml.settings_test);
    }
  }
}

with preference_headers.xml:

<?xml version="1.0" encoding="utf-8"?>

<preference-headers xmlns:android="http://schemas.android.com/apk/res/android">
    <header android:fragment="org.testing.preferencefragment_test.ApplicationPreferencesActivity$SettingsFragmentTest"
            android:title="TEST" />
</preference-headers>

and settings_test.xml:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference
        android:key="pref_test1"
        android:title="Test1_Title"
        android:defaultValue="true" />
</PreferenceScreen>

When I replace import android.support.v4.preference.PreferenceFragment; with import android.preference.PreferenceFragment; its working. Could I do anything about it, or is it a bug/missing feature of this library?

kolavar / android-support-v4-preferencefragment

not working with Preference Headers #9