我正在根据

this example开发应用程序.我在layout-land文件夹中为header.xml定义了横向布局,但是当我将方向更改为横向时,定义的布局不会出现在屏幕中.

知道为什么吗？

谢谢

更新 ：

活动代码：

public class ACENewsFeedActivity extends ListActivity {

// Progress Dialog

private ProgressDialog pDialog;

// Array list for list view

ArrayList> rssItemList = new ArrayList>();

RSSParser rssParser = new RSSParser();

List rssItems = new ArrayList();

RssFeed rssFeed;

private static String TAG_TITLE = "title";

private static String TAG_LINK = "link";

private static String TAG_DESRIPTION = "description";

private static String TAG_PUB_DATE = "pubDate";

//private static String TAG_GUID = "guid"; // not used

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.rss_item_list);

/**

* Calling a backgroung thread will loads recent articles of a website

* @param rss url of website

* */

new loadRSSFeedItems().execute();

}

....

}

横向模式下的XMl布局：

android:id="@+id/layoutHeader"

android:layout_width="fill_parent"

android:layout_height="50dip"

android:layout_alignParentTop="true"

android:background="@layout/header_gradient"

android:orientation="horizontal">

android:id="@+id/btnAddSite"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentRight="true"

android:layout_marginRight="5dip"

android:background="@null"

android:src="@drawable/plus"

android:layout_centerVertical="true" />

android:id="@+id/logo"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_centerVertical="true"

android:src="@drawable/logo" />

android:id="@+id/refreshList"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentBottom="true"

android:layout_centerHorizontal="true"

android:src="@drawable/refresh" />