scaling in Android

I have been recently trying to write a layout for android app. At first I debugged it with a real handset and the layout looked ok. However later I tried running it on emulator but on different resolution. Then it doesn't fit in the screen. Width looks fine, but the height not. My handset resolution is 480x800. Could it have anything to do with aspect ratio. I have all my dimensions in dp. Some of the emulator's resolutions look fine, others however don't. Shouldn't Android scale it by it self?

Heres the look at the layout file:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
 <RelativeLayout
  android:id="@+id/RelativeLayout1"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
  <LinearLayout
       android:orientation="vertical"
       android:layout_width="0px"
          android:layout_height="0px"
          android:focusable="true"
          android:focusableInTouchMode="true"/>
  <EditText
   android:id="@+id/SetAddr"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/StartServer">
  </EditText> 
  <LinearLayout
   android:orientation="horizontal"
   android:id="@+id/LinearLayout2"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:layout_below="@id/SetAddr"
   android:gravity="center_horizontal">
   <Button
    android:id="@+id/PingStart"
    android:layout_width="@dimen/StartButtonWidth"
    android:layout_height="@dimen/StartButtonHeight"
    android:layout_below="@id/SetAddr"
    android:text="@string/Start"
   />

   <Button
    android:id="@+id/PingStop"
    android:layout_width="@dimen/StopButtonWidth"
    android:layout_height="@dimen/StopButtonHeight"
    android:layout_below="@id/SetAddr"
    android:layout_toRightOf="@id/PingStart"
    android:text="@string/Stop"
   />   
  </LinearLayout>
  <TextView

   android:id="@+id/PingResults"
   android:layout_width="@dimen/ResultsViewWidth"
   android:layout_height="@dimen/ResultsViewHeight"
   android:layout_below="@id/LinearLayout2"
   android:textColor="#000"
   android:background="#FFF"
   android:layout_centerHorizontal="true"
   android:scrollbars="vertical"
   />
  <LinearLayout
   android:orientation="horizontal"
   android:id="@+id/LinearLayout3"
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:layout_below="@id/PingResults"
   android:gravity="center_horizontal">

   <Button 
    android:id="@+id/PingStartTrace"
    android:layout_width="@dimen/OptionButtonWidth"
    android:layout_height="@dimen/OptionButtonHeight"
    android:text="@string/Trace" >
   </Button>   
   <Button 
    android:id="@+id/PingStartLookup"
    android:layout_width="@dimen/OptionButtonWidth"
    android:layout_height="@dimen/OptionButtonHeight"
    android:layout_toRightOf="@id/PingStartTrace"
    android:text="@string/Lookup" >
   </Button>
   <Button 
    android:id="@+id/PingStartWebget"
    android:layout_width="@dimen/OptionButtonWidth"
    android:layout_height="@dimen/OptionButtonHeight"
    android:layout_toRightOf="@id/PingStartLookup"
    android:text="@string/WebGet" >
   </Button>
   <Button 
    android:id="@+id/PingStartOptions"
    android:layout_width="@dimen/OptionButtonWidth"
    android:layout_height="@dimen/OptionButtonHeight"
    android:layout_toRightOf="@id/PingStartWebget"
    android:text="@string/Options" >
   </Button>   
  </LinearLayout>   
 </RelativeLayout>    
</LinearLayout>

Dimens file:

<resources>
    <dimen name="StartButtonHeight">50dp</dimen>
    <dimen name="StartButtonWidth">250dp</dimen>
    <dimen name="StopButtonHeight">50dp</dimen>
    <dimen name="StopButtonWidth">60dp</dimen>
    <dimen name="ResultsViewWidth">290dp</dimen>
    <dimen name="ResultsViewHeight">330dp</dimen>
    <dimen name="OptionButtonHeight">50dp</dimen> 
    <dimen name="OptionButtonWidth">75dp</dimen>       
</resources>

On some resolutions I see only 开发者_开发技巧half textview and no buttons below it.