PreferenceActivity用来呈现一种层次化的preferences布局，所有继承自它的activity可以显示一个或多个headers，每一个header都与一个PreferenceFragment相关。PreferenceActivity有两种表现方式：

1.小型屏幕上，只显示headers列表，选择一个header会只显示该header对应的PreferenceFragment；

2.大屏幕上，会把headers列表和当前的Fragment一起显示，选择一个header会切换到该header对应的PreferenceFragment。PreferenceActivity的子类需要实现onBuildHeaders(List)来生成headers列表。

看下面的例子：

package com.example.preferencefragmentdemos;import java.util.List;import android.os.Bundle;
import android.preference.PreferenceActivity;
import android.preference.PreferenceFragment;
import android.preference.PreferenceManager;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.widget.Button;
import android.widget.Toast;public class PreferenceWithHeaders extends PreferenceActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// Add a button to the header list.if (hasHeaders()) {Button button = new Button(this);button.setText("Some action");setListFooter(button);}}/*** Populate the activity with the top-level headers.*/@Overridepublic void onBuildHeaders(List<Header> target) {loadHeadersFromResource(R.xml.preference_headers, target);}/*** This fragment shows the preferences for the first header.*/public static class Prefs1Fragment extends PreferenceFragment {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// Make sure default values are applied.  In a real app, you would// want this in a shared function that is used to retrieve the// SharedPreferences wherever they are needed.//PreferenceManager.setDefaultValues(getActivity(),//R.xml.advanced_preferences, false);// Load the preferences from an XML resourceaddPreferencesFromResource(R.xml.fragmented_preferences);}}/*** This fragment contains a second-level set of preference that you* can get to by tapping an item in the first preferences fragment.*/public static class Prefs1FragmentInner extends PreferenceFragment {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// Can retrieve arguments from preference XML.Log.i("args", "Arguments: " + getArguments());// Load the preferences from an XML resourceaddPreferencesFromResource(R.xml.fragmented_preferences_inner);}}/*** This fragment shows the preferences for the second header.*/public static class Prefs2Fragment extends PreferenceFragment {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// Can retrieve arguments from headers XML.Log.i("args", "Arguments: " + getArguments());// Load the preferences from an XML resourceaddPreferencesFromResource(R.xml.preference_dependencies);}}
}

<?xml version="1.0" encoding="utf-8"?>
<preference-headersxmlns:android="http://schemas.android.com/apk/res/android"><header android:fragment="com.example.preferencefragmentdemos.PreferenceWithHeaders$Prefs1Fragment"android:icon="@drawable/ic_launcher"android:title="Prefs 1"android:summary="An example of some preferences." /><header android:fragment="com.example.preferencefragmentdemos.PreferenceWithHeaders$Prefs2Fragment"android:icon="@drawable/ic_launcher"android:title="Prefs 2"android:summary="Some other preferences you can see."><!-- Arbitrary key/value pairs can be included with a header asarguments to its fragment. --><extra android:name="someKey" android:value="someHeaderValue" /></header><header android:icon="@drawable/ic_launcher"android:title="Intent"android:summary="Launches an Intent."><intent android:action="android.intent.action.VIEW"android:data="http://www.android.com" /></header></preference-headers>

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreenxmlns:android="http://schemas.android.com/apk/res/android"><PreferenceCategoryandroid:title="inline_preferences"><CheckBoxPreferenceandroid:key="checkbox_preference"android:title="title_checkbox_preference"android:summary="summary_checkbox_preference" /></PreferenceCategory><PreferenceCategoryandroid:title="dialog_based_preferences"><EditTextPreferenceandroid:key="edittext_preference"android:title="title_edittext_preference"android:summary="summary_edittext_preference"android:dialogTitle="dialog_title_edittext_preference" /></PreferenceCategory><PreferenceCategoryandroid:title="launch_preferences"><!-- This PreferenceScreen tag sends the user to a new fragment ofpreferences.  If running in a large screen, they can be embeddedinside of the overall preferences UI. --><PreferenceScreenandroid:fragment="com.example.preferencefragmentdemos.PreferenceWithHeaders$Prefs1FragmentInner"android:title="title_fragment_preference"android:summary="summary_fragment_preference"><!-- Arbitrary key/value pairs can be included for fragment arguments --><extra android:name="someKey" android:value="somePrefValue" /></PreferenceScreen><!-- This PreferenceScreen tag sends the user to a completely differentactivity, switching out of the current preferences UI. --><PreferenceScreenandroid:title="title_intent_preference"android:summary="summary_intent_preference"><intent android:action="android.intent.action.VIEW"android:data="http://www.baidu.com" /></PreferenceScreen></PreferenceCategory><PreferenceCategoryandroid:title="preference_attributes"><CheckBoxPreferenceandroid:key="parent_checkbox_preference"android:title="title_parent_preference"android:summary="summary_parent_preference" /><!-- The visual style of a child is defined by this styled theme attribute. --><CheckBoxPreferenceandroid:key="child_checkbox_preference"android:dependency="parent_checkbox_preference"android:layout="?android:attr/preferenceLayoutChild"android:title="title_child_preference"android:summary="summary_child_preference" /></PreferenceCategory></PreferenceScreen>

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" ><EditTextPreferenceandroid:key="edittext_preference"android:title="title_edittext_preference"android:summary="summary_edittext_preference"android:dialogTitle="dialog_title_edittext_preference" /></PreferenceScreen>

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" ><CheckBoxPreference android:key="auto_save"android:title="自动保存进度"android:summary="用来自动保存进度"/></PreferenceScreen>