samples/training/threadsample/res/layout/gridlist.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
-->
<FrameLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_gravity="center"
	android:layout_width="0.0dip" 
    android:layout_height="fill_parent"
	android:layout_weight="1.0">
    <GridView 
        android:id="@android:id/list"
		android:alwaysDrawnWithCache="true" 
        android:layout_width="fill_parent"
		android:layout_height="wrap_content" 
        android:cacheColorHint="@android:color/black"/>
        <LinearLayout 
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/progressRoot"
            android:gravity="center"
            android:visibility="invisible" 
            android:layout_width="fill_parent"
            android:layout_height="fill_parent">
<ProgressBar android:layout_gravity="center_vertical"
			android:paddingLeft="10.0dip" android:layout_width="wrap_content"
			android:layout_height="wrap_content" />
	</LinearLayout>
</FrameLayout>