Android设置Settings：预读取设置的选项和更新设置结果【2】

本文在文章1的基础上，增加预读取历史的修改、设置值更新到设置选项中，同时，每一次更新都会实时更新到设置栏中。
 res/xml目录下的preferences.xml:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" ><PreferenceCategory android:title="【第1组】" ><ListPreferenceandroid:dialogTitle="list dialog title"android:entries="@array/citys"android:entryValues="@array/citys"android:key="list_key"android:summary="list summary"android:title="list title" /></PreferenceCategory><PreferenceCategory android:title="【第2组】" ><EditTextPreferenceandroid:defaultValue="缺省值1"android:key="edit_text_key_1"android:summary="edit summary"android:title="edit text 1" /><CheckBoxPreferenceandroid:defaultValue="true"android:key="checkbox_key"android:summary="checkbox summary"android:title="checkbox title" /></PreferenceCategory><!-- 点击将浏览和打开网页 --><Preferenceandroid:summary="http://blog.csdn.net/zhangphil"android:title="浏览网页" ><intentandroid:action="android.intent.action.VIEW"android:data="http://blog.csdn.net/zhangphil" /></Preference><!-- 此处将跳转到下一屏设置 --><PreferenceScreenandroid:key="preference_screen_2_key"android:persistent="false"android:title="PreferenceScreen 2" ><EditTextPreferenceandroid:defaultValue="缺省值2"android:key="edit_text_key_2"android:summary="edit summary"android:title="edit text 2" /></PreferenceScreen></PreferenceScreen>

需要的res/values/arrays.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources><string-array name="citys"><item>成都</item><item>北京</item><item>上海</item></string-array></resources>

上层Java代码：

package zhangphil.settings;import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;public class MainActivity extends PreferenceActivity {private MyOnSharedPreferenceChangeListener mOnSharedPreferenceChangeListener = new MyOnSharedPreferenceChangeListener();private EditTextPreference mEditTextPreference;private final String A_KEY = "edit_text_key_1";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// 通用的读取设置的某个值的方法SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);String s = sharedPreferences.getString(A_KEY, "暂时为空");// 添加设置的选项addPreferencesFromResource(R.xml.preferences);// 预读取。为PreferenceActivity中的某个设置选项初始化值mEditTextPreference = (EditTextPreference) findPreference(A_KEY);mEditTextPreference.setSummary(s);// 注册添加设置的项数据发生变化时候的监听sharedPreferences.registerOnSharedPreferenceChangeListener(mOnSharedPreferenceChangeListener);}@Overrideprotected void onResume() {super.onResume();getPreferenceScreen().getSharedPreferences().registerOnSharedPreferenceChangeListener(mOnSharedPreferenceChangeListener);}@Overrideprotected void onPause() {super.onPause();getPreferenceScreen().getSharedPreferences().unregisterOnSharedPreferenceChangeListener(mOnSharedPreferenceChangeListener);}private class MyOnSharedPreferenceChangeListener implements OnSharedPreferenceChangeListener {@Overridepublic void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {if (key.equals(A_KEY)) {// 更新String s = sharedPreferences.getString(A_KEY, "NULL");mEditTextPreference.setSummary(s);}}}
}

相关文章和开发文档：
【1】《Android设置Settings实现：PreferenceActivity【1】》链接地址：http://blog.csdn.net/zhangphil/article/details/50154513
【2】Android谷歌官方Settings开发文档：http://developer.android.com/guide/topics/ui/settings.html