MapView not supporting layout_height=wrap_content

I'm building a layout that contains two buttons and a MapView. The buttons should be placed above and below the MapView. I've tried several combinations of layouts (Relative, Linear, Frame...), but the MapView does not support the layout_height=wrap_content unless I use a specific height like layout_height="200dp".

The tope button is displayed, but the bottom button is not. Below is my test XML file.

Any suggestions?

android:layout_width="fill_parent" android:layout_height="fill_parent" >

<Button     
    android:id="@+id/btn1" 
    android:layout_width="fill_parent"          
    android:layout_height="wrap_content"
    android:text="Button1" 
    android:background="#FF0000" />

<com.google.android.maps.MapView
    android:id="@+id/map1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:apiKey="my map key (removed for example)"
/>           

<Button     
    android:id="@+id/btn2" 
    android:layout_width="fill_parent"          
    android:layout_height="wrap_content开发者_运维知识库"
    android:text="Button2"
    android:background="#00FF00" />      

I had the same issue (my mapview was between two layouts instead of buttons), and solved it with "height=0dp" and "weight=1" so the mapview adjusts to the above and below layouts.

<com.google.android.maps.MapView
  android:id="@+id/map1"
  android:layout_width="fill_parent"
  android:layout_height="0dp"
  android:layout_weight="1"
  android:apiKey="my map key (removed for example)"
/> 

I'm on a brand new machine and don't have anything to test this with, but this might work:

<RelativeLayout 
android:layout_width="fill_parent"          
android:layout_height="fill_parent">
<Button     
    android:id="@+id/btn1" 
    android:layout_width="fill_parent"          
    android:layout_height="wrap_content"
    android:text="Button1" 
    android:background="#FF0000" />

<Button     
    android:id="@+id/btn2" 
    android:layout_width="fill_parent"          
    android:layout_height="wrap_content"
    android:text="Button2"
    android:background="#00FF00" />      

<com.google.android.maps.MapView
    android:id="@+id/map1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:apiKey="my map key (removed for example)"
    android:layout_below="@id/btn1"
    android:layout_above="@id/btn2"
/></RelativeLayout>