问布局中的布局<layout>在基本布局文件夹中没有声明[错误]

EN

<?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="fill_parent"
    android:orientation="vertical"
    android:background="@null" >

      <FrameLayout
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical" >

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="top|center_horizontal"
            android:adjustViewBounds="true"
            android:contentDescription="@string/hello_world"
            android:src="@drawable/loading_top" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|center_horizontal"
            android:adjustViewBounds="true"
            android:contentDescription="@string/hello_world"
            android:src="@drawable/loading_bottom" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:contentDescription="@string/hello_world"
            android:background="@color/white"
            android:layout_marginBottom="5dp"
            android:paddingTop="10dp"
            android:paddingBottom="10dp"
            android:src="@drawable/loading_logo" />

        <ImageView
            android:id="@+id/loading"
            android:layout_width="fill_parent"
            android:layout_height="match_parent"
            android:layout_gravity="center|center_vertical"
            android:layout_marginBottom="0dp"
            android:layout_marginTop="0dp"
            android:contentDescription="@string/hello_world"
            android:scaleType="fitXY"
            android:src="@null" />
    </FrameLayout>
</LinearLayout>