自定义PreferenceActivity——修改Preference样式、加顶部布局
首先在res/xml文件夹下建立preferences.xml
<?xml version="1.0" encoding="utf-8"?><PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" > <PreferenceCategory android:title="inline_preferences" > <CheckBoxPreference android:key="checkbox_preference" android:summary="summary_toggle_preference" android:title="title_toggle_preference" /> </PreferenceCategory> <PreferenceCategory android:title="dialog_based_preferences" > <EditTextPreference android:dialogTitle="dialog_title_edittext_preference" android:key="edittext_preference" android:summary="summary_edittext_preference" android:title="title_edittext_preference" /> <ListPreference android:dialogTitle="dialog_title_list_preference" android:entries="@array/entries_list_preference" android:entryValues="@array/entryvalues_list_preference" android:key="list_preference" android:summary="summary_list_preference" android:title="title_list_preference" /> </PreferenceCategory> <PreferenceCategory android:title="launch_preferences" > <PreferenceScreen android:key="screen_preference" android:summary="summary_screen_preference" android:title="title_screen_preference" > <CheckBoxPreference android:key="next_screen_checkbox_preference" android:summary="summary_next_screen_toggle_preference" android:title="title_next_screen_toggle_preference" /> </PreferenceScreen> <PreferenceScreen android:summary="summary_intent_preference" android:title="title_intent_preference" > <intent android:action="android.intent.action.VIEW" android:data="http://www.android.com" /> </PreferenceScreen> </PreferenceCategory> <PreferenceCategory android:title="preference_attributes" > <CheckBoxPreference android:key="parent_checkbox_preference" android:summary="summary_parent_preference" android:title="title_parent_preference" /> <CheckBoxPreference android:dependency="parent_checkbox_preference" android:key="child_checkbox_preference" android:layout="?android:attr/preferenceLayoutChild" android:summary="summary_child_preference" android:title="title_child_preference" /> </PreferenceCategory></PreferenceScreen>
然后在代码中加载preferences.xml
public class MyPreferenceActivity extends PreferenceActivity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);addPreferencesFromResource(R.xml.preferences);}}这样就创建了从xml加载preferences的默认的PreferenceActivity。
在加载了preferences.xml的PreferenceActivity中， a top-level preference是一个PreferenceScreen，可用getPreferenceScreen()获取。PreferenceScreen和PreferenceCategory继承自PreferenceGroup，它们可以包含一个或多个PreferenceScreen，PreferenceCategory或者是具体的preference（如EditTextPreference、CheckBoxPreference）。由于PreferenceScreen，PreferenceCategory，EditTextPreference等都是继承自Preference，因此可以通过setLayoutResource()方法设置自己的布局样式。下面将遍历所有Preference，并设置自己的样式，代码如下：
private void setLayoutResource(Preference preference) {if (preference instanceof PreferenceScreen) {PreferenceScreen ps = (PreferenceScreen) preference;ps.setLayoutResource(R.layout.preference_screen);int cnt = ps.getPreferenceCount();for (int i = 0; i < cnt; ++i) {Preference p = ps.getPreference(i);setLayoutResource(p);}} else if (preference instanceof PreferenceCategory) {PreferenceCategory pc = (PreferenceCategory) preference;pc.setLayoutResource(R.layout.preference_category);int cnt = pc.getPreferenceCount();for (int i = 0; i < cnt; ++i) {Preference p = pc.getPreference(i);setLayoutResource(p);}} else {preference.setLayoutResource(R.layout.preference);}}preference_screen.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center_vertical" android:minHeight="?android:attr/listPreferredItemHeight" android:paddingRight="?android:attr/scrollbarSize" > <ImageView android:id="@+android:id/icon" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:src="@drawable/ic_launcher"/> <RelativeLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="6dip" android:layout_marginLeft="15dip" android:layout_marginRight="6dip" android:layout_marginTop="6dip" android:layout_weight="1" > <TextView android:id="@+android:id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:ellipsize="marquee" android:fadingEdge="horizontal" android:singleLine="true" android:textAppearance="@android:style/TextAppearance.Large" android:textColor="#FFFF1234" /> <TextView android:id="@+android:id/summary" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@android:id/title" android:layout_below="@android:id/title" android:maxLines="4" android:textAppearance="@android:style/TextAppearance.Small" android:textColor="#FF888888" /> </RelativeLayout> <LinearLayout android:id="@+android:id/widget_frame" android:layout_width="wrap_content" android:layout_height="match_parent" android:gravity="center_vertical" android:orientation="vertical" /></LinearLayout>
preference_category.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:background="#FF123456" android:gravity="center_vertical" android:minHeight="?android:attr/listPreferredItemHeight" android:paddingRight="?android:attr/scrollbarSize" > <ImageView android:id="@+android:id/icon" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:src="@drawable/ic_launcher" /> <RelativeLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="6dip" android:layout_marginLeft="15dip" android:layout_marginRight="6dip" android:layout_marginTop="6dip" android:layout_weight="1" > <TextView android:id="@+android:id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:ellipsize="marquee" android:fadingEdge="horizontal" android:singleLine="true" android:textAppearance="@android:style/TextAppearance.Large" android:textColor="#FFFF0000" /> <TextView android:id="@+android:id/summary" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@android:id/title" android:layout_below="@android:id/title" android:maxLines="4" android:textAppearance="@android:style/TextAppearance.Small" android:textColor="#FF00FF00" /> </RelativeLayout> <LinearLayout android:id="@+android:id/widget_frame" android:layout_width="wrap_content" android:layout_height="match_parent" android:gravity="center_vertical" android:orientation="vertical" /></LinearLayout>
preference.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center_vertical" android:minHeight="?android:attr/listPreferredItemHeight" android:paddingRight="?android:attr/scrollbarSize" > <ImageView android:id="@+android:id/icon" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" /> <RelativeLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="6dip" android:layout_marginLeft="15dip" android:layout_marginRight="6dip" android:layout_marginTop="6dip" android:layout_weight="1" > <TextView android:id="@+android:id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:ellipsize="marquee" android:fadingEdge="horizontal" android:singleLine="true" android:textAppearance="@android:style/TextAppearance.Medium" android:textColor="#FF00FFFF" /> <TextView android:id="@+android:id/summary" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@android:id/title" android:layout_below="@android:id/title" android:maxLines="4" android:textAppearance="@android:style/TextAppearance.Small" android:textColor="#FFFFFF00" /> </RelativeLayout> <LinearLayout android:id="@+android:id/widget_frame" android:layout_width="wrap_content" android:layout_height="match_parent" android:gravity="center_vertical" android:orientation="vertical" /></LinearLayout>
下面介绍加顶部布局，其实也是添加加一个preference，通过preferenceScreen的addPreference添加。首先自定义一个PreferenceHead，布局中有一个返回按钮。
package com.preference.main;import android.content.Context;import android.preference.Preference;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class PreferenceHead extends Preference {private OnClickListener onBackButtonClickListener;public PreferenceHead(Context context) {super(context);setLayoutResource(R.layout.preference_head);}@Overrideprotected void onBindView(View view) {super.onBindView(view);Button btBack = (Button) view.findViewById(R.id.back);btBack.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {if (onBackButtonClickListener != null) {onBackButtonClickListener.onClick(v);}}});}public void setOnBackButtonClickListener(OnClickListener onClickListener) {this.onBackButtonClickListener = onClickListener;}}<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="60.0dip" android:background="#8000FF00" android:gravity="center_vertical" > <Button android:id="@+id/back" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_margin="10.0dip" android:text="返回" /></LinearLayout>
然后在代码中实现
PreferenceHead ph = new PreferenceHead(this);ph.setOnBackButtonClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {finish();}});ph.setOrder(0);preferenceScreen.addPreference(ph);这样就完成了一个具有返回按钮的顶部布局的 PreferenceActivity，效果图如下
