title: admob ads do not show up
body: <p>I have successfully made my admob ads show up on the sample code provided by Google at <a href="http://code.google.com/mobile/ads/docs/android/fundamentals.html" rel="nofollow">http://code.google.com/mobile/ads/docs/android/fundamentals.html</a>, but when it comes to my own app, they do not show up.</p>
  
  <p>I've read some related questions but it doesn't seem to be an issue for the LinearLayout which I am using. One thing to notice is that in my app it extends ListActivity instead of Activity.</p>
  
  <pre><code>   &lt;?xml version="1.0" encoding="utf-8"?&gt;
      &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:ads="http://schemas.android.com/apk/res/com.mypackage.myapp" 
         android:orientation="vertical"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"&gt;
        &lt;LinearLayout
          android:orientation="horizontal"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:layout_weight="2"&gt;
  
          &lt;com.google.ads.AdView android:id="@+id/adView"                          
              android:layout_width="wrap_content"                          
              android:layout_height="fill_parent"                          
              ads:adUnitId="myadmobid"                          
              ads:adSize="BANNER"/&gt;  
      &lt;/LinearLayout&gt;
  
      &lt;LinearLayout
          android:orientation="horizontal"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:layout_weight="2"&gt;
          &lt;TextView
              android:id="@+id/hottopictab"
              android:text="Deal"
              android:gravity="center_horizontal|center_vertical"
              android:background="#000000"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:textStyle="bold"
        android:typeface ="sans"
              android:layout_weight="1"/&gt;
  
          &lt;TextView
              android:id="@+id/newtopictab"
              android:text="()"
              android:gravity="center_horizontal|center_vertical"
              android:background="#000000"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:textStyle="bold"
        android:typeface ="sans"
              android:layout_weight="1"/&gt;
  
          &lt;TextView
              android:id="@+id/recommendtab"
              android:text=""
              android:gravity="center_horizontal"
              android:background="#000000"
              android:layout_width="wrap_content"
              android:layout_height="fill_parent"
              android:layout_weight="1"/&gt;
  
      &lt;ImageButton 
              android:layout_height="fill_parent"
              android:id="@+id/refresh"
              android:background="#000000"
              android:src="@drawable/refresh"     
              android:layout_width="wrap_content" 
              android:layout_marginRight="6dip"    
          /&gt; 
  
  
     &lt;/LinearLayout&gt;            
     &lt;LinearLayout
          android:orientation="vertical"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:layout_weight="40"&gt;
  
          &lt;ListView
              android:id="@android:id/list"
              android:text="row one"
              android:textSize="15pt"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:layout_weight="1"/&gt; 
  
      &lt;/LinearLayout&gt;      
  &lt;/LinearLayout&gt;
  </code></pre>