java - live wallpaper-settings button is not working -

okay, first application working on, works fine until wanted add settings button live wallpaper, problem is, when hit "settings" comes message of "live wallpaper picker has stopped". here's code

android manifest

<manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.live.zaki"   android:versioncode="1"    android:versionname="1.0" >     <uses-sdk     android:minsdkversion="10"     android:targetsdkversion="16" />     <application      android:allowbackup="true"     android:icon="@drawable/ic_launcher"     android:label="@string/app_name"     android:theme="@style/apptheme" >     <activity         android:name="com.example.ui.mainactivity"         android:configchanges="orientation|keyboardhidden|screensize"         android:exported="true"         android:label="@string/app_name"         android:theme="@style/fullscreentheme" >          />           <intent-filter>             <action android:name="android.intent.action.main" />              <category android:name="android.intent.category.launcher" />         </intent-filter>     </activity>     android:label="@string/appname"     android:icon="@drawable/icon">       <service         android:name="com.live.zaki.customwallpaper"         android:label="@string/appname"         android:permission="android.permission.bind_wallpaper" >         <intent-filter>             <action android:name="android.service.wallpaper.wallpaperservice" />         </intent-filter>          <meta-data             android:name="android.service.wallpaper"             android:resource="@xml/wallpaper" />     </service>      <activity         android:name="com.example.ui.secondactivity"         android:label="home" >     </activity>     <activity       android:name=".prefsactivity"     android:theme="@android:style/theme.black.notitlebar" >     </activity>     </application>       </manifest> 

wallpaper.xml

<wallpaper xmlns:android="http://schemas.android.com/apk/res/android"  android:thumbnail="@drawable/icon" android:description="@string/appdescription" android:settingsactivity="com.live.zaki.prefsactivity" /> 

prefs.xml

     <preferencescreen xmlns:android="http://schemas.android.com/apk/res/android"> <preferencecategory      android:title="@string/general_lwp_settings">      <checkboxpreference         android:key="lwp_o_scroll_lock_key"         android:summary="@string/lwp_o_scroll_lock_summary"         android:title="@string/lwp_o_scroll_lock_title"         android:defaultvalue="false" />   <checkboxpreference         android:key="lwp_auto_animation_key"         android:summary="@string/lwp_auto_animation_summary"         android:title="@string/lwp_auto_animation_title"         android:defaultvalue="false" />    </preferencecategory> 

prefsactivity.java

public class prefsactivity extends preferenceactivity{@override protected void oncreate(bundle savedinstancestate) {  super.oncreate(savedinstancestate);  addpreferencesfromresource(com.live.zaki.r.xml.prefs);  }  } 

i haven't yet configured preference logic on main livewallpaper.java code, want settings menu popup "two checkbox in case". possible ?? if me, great !! tips, tutorials !! here's application results without settings,

https://drive.google.com/file/d/0b44qwxqhh5irnfrnykhzddhpm00/edit?usp=sharing

buddy add exported flag in setting activity , set true android:exported="true"