android progressbar 藏到imageview下面

  实现布局：imageview下藏着一个progressbar，当imageview没有加载完成时，会显示一个progressbar，当imageivew加载完成后，就会自动的覆盖下面的progressbar

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/shape_border"
        android:orientation="vertical" >
         <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
		        <ProgressBar
		            android:id="@+id/progressBar1"
		            style="?android:attr/progressBarStyleSmall"
		            android:layout_width="wrap_content"
		            android:layout_height="wrap_content"
		           	android:layout_centerInParent="true"
		            android:layout_marginLeft="97dp" />
		        <ImageView
		            android:id="@+id/image"
		            android:layout_width="fill_parent"
		            android:layout_height="wrap_content"
		            android:layout_marginBottom="@dimen/edit_padding"
		            android:adjustViewBounds="true"
		            android:scaleType="centerCrop" />
        </RelativeLayout>
        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" >
            <TextView
                    android:id="@+id/tv_cn_name"
                    style="@style/details_text_style"
                    android:text="餐厅名称" />
            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentRight="true" >
                <TextView
                    style="@style/details_text_style"
                    android:text="赞" />
            </LinearLayout>
        </RelativeLayout>
    </LinearLayout>
</LinearLayout>