title: findViewById returns null for WebView
body: <p>I'm trying to build an android app, which just consists of a webview. I took the example from <a href="http://developer.android.com/guide/webapps/webview.html" rel="noreferrer">android dev site</a> and modified it. But as simple as it looks, every call to findViewById results in a null pointer.
  The .java file:</p>
  
  <pre><code>    public class MainActivity extends Activity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
  
          WebView webView = (WebView) findViewById(R.id.webview);
          // returns null pointer 
          webView.loadUrl("file:///android_asset/index.html");
  
          setContentView(webView);
      }
  }
  </code></pre>
  
  <p>The layout file:</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:paddingBottom="@dimen/activity_vertical_margin"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      android:orientation="horizontal"
      tools:context=".MainActivity" &gt;
  
      &lt;WebView
          android:id="@+id/webview"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent" /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>And I put following line into the manifest:</p>
  
  <pre><code>&lt;uses-permission android:name="android.permission.INTERNET" /&gt;
  </code></pre>
  
  <p>I'm puzzled ...</p>