title: The sample of Google Maps Android API v2 com.example.mapdemo can not find file "R.java"
body: <p>Today I have read the document of Google Maps Android API v2, it said the project of <code>android-sdk\extras\google\google_play_services\samples\maps</code> can run,
  but after I imported into eclipse and set the libraries of <code>android-support-v4.jar</code> and google-play-services.jar correctly, <code>import com.example.mapdemo.R;</code> in <code>FeatureView.java</code> (at line 24) can not find the file <code>R.java.</code></p>
  
  <p>almost all the java file in <code>com.example.mapdemo</code> need class "R", for example, the file BasicMapActivity.java need R in line 41 "<code>setContentView(R.layout.basic_demo);</code>" and line 71 <code>mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();</code>"
  can someone tell me how to find the class "R"?</p>
  
  <p>R</p>
  
  <pre><code>.java can not create automatically because the file multimap_demo.xml have some errors in
  &lt;br&gt;&lt;br&gt;    &amp;lt;fragment
  &lt;br&gt;      android:id="@+id/map3"
  &lt;br&gt;      android:layout_width="match_parent"
  &lt;br&gt;      android:layout_height="match_parent"
  &lt;br&gt;      android:layout_weight="0.5"
  &lt;br&gt;      class="com.google.android.gms.maps.SupportMapFragment"
  &lt;br&gt;      map:cameraTargetLat="48.85"
  &lt;br&gt;      map:cameraTargetLng="2.35"
  &lt;br&gt;      map:cameraZoom="8"/&amp;gt;
  &lt;br&gt;&lt;br&gt;
  </code></pre>
  
  <p>eclipse said "cameraTargetLat", "cameraTargetLng" and "cameraZoom" can not recognized.
  The error information:</p>
  
  <pre><code>Multiple annotations found at this line:
      - error: No resource identifier found for attribute 'cameraTargetLat' in package 'com.example.mapdemo'
      - error: No resource identifier found for attribute 'cameraTargetLng' in package 'com.example.mapdemo'
      - error: No resource identifier found for attribute 'cameraZoom' in package 'com.example.mapdemo'
  
  I do not know why.
  
  If I change the code like this:
  &lt;br&gt;&lt;br&gt;    &amp;lt;fragment
  &lt;br&gt;      android:id="@+id/map3"
  &lt;br&gt;      android:layout_width="match_parent"
  &lt;br&gt;      android:layout_height="match_parent"
  &lt;br&gt;      android:layout_weight="0.5"
  &lt;br&gt;      class="com.google.android.gms.maps.SupportMapFragment"/&amp;gt;
  &lt;br&gt;&lt;br&gt;
  </code></pre>
  
  <p>the errors disappeared, but i do not know if it can run.</p>