关于tabhost的宽度问题~~~~急！！！

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >    <ImageView
        android:id="@+id/logo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />    <TabHost
        android:id="@+id/mytabhost"
        android:layout_width="250dp"
        android:layout_height="fill_parent"
        android:layout_marginLeft="50dp" >        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:background="#000000" >            <TabWidget
                android:id="@android:id/tabs"
                android:layout_width="fill_parent"
                android:layout_height="50dp"
                android:layout_alignParentTop="true"
                android:background="#ff00ee"
                android:gravity="bottom"
                android:orientation="horizontal" >
            </TabWidget>            <FrameLayout
                android:id="@android:id/tabcontent"
                android:layout_width="match_parent"
                android:layout_height="fill_parent"
                android:layout_below="@android:id/tabs" >
            </FrameLayout>
        </RelativeLayout>
    </TabHost>    <ImageView
        android:id="@+id/logo"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/mytabhost"
        android:orientation="horizontal" >        <EditText
            android:id="@+id/et_search"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:hint="@string/search_hint" />        <Button
            android:id="@+id/btn_search"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/search" />
    </LinearLayout></RelativeLayout>加载后效果如下
请问 红色部分有没有办法延伸到屏幕的两头Androidtabhost布局