Androidのライブ壁紙をActivityから指定したい

Intent intent = new Intent(); 
intent.setAction(WallpaperManager.ACTION_LIVE_WALLPAPER_CHOOSER); 
startActivity(intent); 

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingLeft="6dip" android:paddingRight="6dip" android:paddingTop="6dip" android:paddingBottom="6dip" android:minHeight="?android:attr/listPreferredItemHeight"> 
<ListView android:id="@android:id/list" android:layout_width="fill_parent" android:layout_height="fill_parent" android:drawSelectorOnTop="false"/> 
<TextView android:id="@android:id/empty" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center" android:visibility="gone" android:text="@string/live_wallpaper_empty" android:textAppearance="?android:attr/textAppearanceMedium"/> 
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:paddingLeft="6dip" android:paddingRight="6dip" android:paddingTop="6dip" android:paddingBottom="6dip" android:minHeight="?android:attr/listPreferredItemHeight"> 
<ImageView android:id="@+id/thumbnail" android:layout_width="@dimen/live_wallpaper_thumbnail_width" android:layout_height="@dimen/live_wallpaper_thumbnail_width" android:layout_gravity="center_vertical" android:scaleType="centerCrop"/> 
<LinearLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="10dip" android:layout_marginRight="8dip" android:layout_centerVertical="true" android:layout_toRightOf="@id/thumbnail" android:orientation="vertical"> 
<TextView android:id="@+id/title_author" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceMedium" android:singleLine="true" android:ellipsize="marquee"/> 
<TextView android:id="@+id/description" android:layout_width="fill_parent" android:layout_height="wrap_content" android:textAppearance="?android:attr/textAppearanceSmall" android:maxLines="3"/> 
</LinearLayout> 
</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?> 
<resources> 
    <color name="live_wallpaper_thumbnail_background">#000000</color> 
    <color name="live_wallpaper_thumbnail_text_color">#ffffff</color> 
</resources>

<?xml version="1.0" encoding="utf-8"?> 
<resources> 
    <dimen name="live_wallpaper_thumbnail_width">50dp</dimen> 
    <dimen name="live_wallpaper_thumbnail_height">50dp</dimen> 
    <dimen name="live_wallpaper_thumbnail_text_size">50dp</dimen> 
    <dimen name="live_wallpaper_thumbnail_text_offset">50dp</dimen> 
</resources>

LiveWallpaperPreview.showPreview(this , REQUEST_PREVIEW, intent, info);

	static final String EXTRA_LIVE_WALLPAPER_INTENT = "android.live_wallpaper.intent";
	static final String EXTRA_LIVE_WALLPAPER_SETTINGS = "android.live_wallpaper.settings";
	static final String EXTRA_LIVE_WALLPAPER_PACKAGE = "android.live_wallpaper.package";

	public void onItemClick(AdapterView<?> parent, View view, int position,
			long id) {
		final Intent intent = mWallpaperIntents.get(position);
		final WallpaperInfo info = mWallpaperInfos.get(position);
		//LiveWallpaperPreview.showPreview(this, REQUEST_PREVIEW, intent, info);
		//Intent preview = new Intent(this, LiveWallpaperPreview.class);
		String clazz = "com.android.wallpaper.livepicker.LiveWallpaperPreview";
		Intent preview = new Intent(Intent.ACTION_MAIN);
		int idx = clazz.lastIndexOf('.');
		String pkg = clazz.substring(0, idx);
		preview.setClassName(pkg, clazz);
		preview.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
		preview.putExtra(EXTRA_LIVE_WALLPAPER_INTENT, intent);
		preview.putExtra(EXTRA_LIVE_WALLPAPER_SETTINGS,
				info.getSettingsActivity());
		preview.putExtra(EXTRA_LIVE_WALLPAPER_PACKAGE, info.getPackageName());
		this.startActivityForResult(preview, REQUEST_PREVIEW);
	}

FATAL EXCEPTION: main 
java.lang.SecurityException: Permission Denial: starting Intent { act=android.intent.action.MAIN flg=0x10000000 cmp=com.android.wallpaper.livepicker/.LiveWallpaperPreview (has extras) } from ProcessRecord{4073a338 8432:com.sample.android.TestCase/10077} (pid=8432, uid=10077) requires null 
    at android.os.Parcel.readException(Parcel.java:1322) 
    at android.os.Parcel.readException(Parcel.java:1276) 
    at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:1351) 
    at android.app.Instrumentation.execStartActivity(Instrumentation.java:1374) 
    at android.app.Activity.startActivityForResult(Activity.java:2827) 
    at com.sample.android.TestCase.LiveWallpaperListActivity.onItemClick(LiveWallpaperListActivity.java:201) 
    at android.widget.AdapterView.performItemClick(AdapterView.java:284) 
    at android.widget.ListView.performItemClick(ListView.java:3513) 
    at android.widget.AbsListView$PerformClick.run(AbsListView.java:1812) 
    at android.os.Handler.handleCallback(Handler.java:587) 
    at android.os.Handler.dispatchMessage(Handler.java:92) 
    at android.os.Looper.loop(Looper.java:130) 
    at android.app.ActivityThread.main(ActivityThread.java:3683) 
    at java.lang.reflect.Method.invokeNative(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:507) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
    at dalvik.system.NativeStart.main(Native Method)