PreferenceActivity的使用

    今天项目用到PreferenceActivity时，也是今天才刚接触，于是自己稍微研究了下，它主要用作设置界面，用于一个界面同时保存多个设置的数据，其底层也是用sharedProperty来实现的。

 使用步骤：

1.自己写一个继承PreferenceActivity的类 如

public class SettingsActivity extends PreferenceActivity {

    
     /** Called when the activity is first created. */
    @Override
 public void onCreate(Bundle savedInstanceState) {
     requestWindowFeature(Window.FEATURE_NO_TITLE);
    super.onCreate(savedInstanceState);
    //这是把res/xml下的PreferenceScreen加入到PreferenceActivity 中

    addPreferencesFromResource(R.xml.preferences);

    setContentView(R.layout.settings);

  }

}

 

2.必须在res/xml文件下建立一个preferences.xml文件

preferences.xml内容

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

 <PreferenceCategory android:title="@string/app_name"
  android:summary="Application settings">

  <EditTextPreference android:key="user_name"
   android:defaultValue="@null"
   android:title="User Name"
   android:summary="Personalize your Jamendo client" />
  <ListPreference
                android:key="download_format"
                android:title="Download format"
                android:summary="Select your preferred codec"
                android:entries="@array/stream_codecs"
                android:entryValues="@array/stream_codecs_values" />
  <CheckBoxPreference android:key="wifi_only"
   android:defaultValue="false"
   android:title="Wifi only mode"
   android:summary="Listen only in wifi network area" />
  <CheckBoxPreference android:key="roaming_protection"3.
   android:defaultValue="true"
   android:title="Roaming Protection"
   android:summary="Disable listening abroad" />
 </PreferenceCategory>

 <PreferenceCategory android:title="3rd Party Applications"
  android:summary="Interaction with outside applications">

  <CheckBoxPreference android:key="lastfm_scrobble"
   android:defaultValue="false"
   android:title="Last.fm Scrobbling"
   android:summary="Requires official last.fm client" />
 </PreferenceCategory>
</PreferenceScreen>

 

3.建立PreferenceActivity显示的布局文件settings.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical" android:layout_width="fill_parent"
 android:layout_height="fill_parent" android:background="#000000">

 <LinearLayout android:layout_width="fill_parent"
  android:layout_height="wrap_content" android:background="@drawable/gradient_dark_purple"
  android:orientation="horizontal" android:gravity="center"
  android:minHeight="75dip">
  <LinearLayout android:layout_height="wrap_content"
   android:minHeight="75dip" android:layout_width="fill_parent"
   android:orientation="horizontal" android:gravity="center_vertical"
   android:paddingLeft="13dip" android:paddingRight="13dip">
   <ImageView android:layout_width="48dip"
    android:layout_height="48dip" android:src="@drawable/settings"></ImageView>
   <LinearLayout android:layout_height="wrap_content"
    android:paddingLeft="13dip" android:orientation="vertical"
    android:layout_width="fill_parent">
    <TextView android:layout_width="wrap_content"
     android:singleLine="true" android:layout_height="wrap_content"
     android:textSize="18dip" android:textColor="#ffffff" android:text="@string/settings"></TextView>
    <TextView android:layout_width="wrap_content"
     android:layout_height="wrap_content" android:textSize="12dip"
     android:textColor="#ffffff"></TextView>
    <TextView android:id="@+id/ItemsCountTextView"
     android:layout_width="wrap_content" android:layout_height="wrap_content"
     android:layout_gravity="right" android:textSize="12dip"
     android:textColor="#ffffff" android:text=" "></TextView>
   </LinearLayout>
  </LinearLayout>
 </LinearLayout>

<!--  这个用于显示PreferenceActivity中preferenceScreen的-->
 <ListView android:layout_width="fill_parent" android:id="@android:id/list"
  android:layout_weight="1" android:layout_height="fill_parent">
 </ListView>
</LinearLayout>

就只这么简单 完了，也许有些朋友会奇怪  为什么在settting.xml中能显示preference.xml中preferencescreen呢

进入PreferenceActivity中才知道 

因为PreferenceActivity 是继承ListActivity的

它其中有个 private void bindPreferences() {
        final PreferenceScreen preferenceScreen = getPreferenceScreen();
        if (preferenceScreen != null) {

        //这就是为什么在settting.xml中能显示preference.xml中preferencescreen的原因
            preferenceScreen.bind(getListView());
            if (mSavedInstanceState != null) {
                super.onRestoreInstanceState(mSavedInstanceState);
                mSavedInstanceState = null;
            }
        }
    }