title: Can not get element from layout
body: <p>I have 2 activities. The 2nd .xml looks like:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      &gt;
      &lt;ListView 
              android:id="@+id/TrainsListView"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent" 
          /&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>Part of manifest:</p>
  
  <p>
          
              
              
          
      </p>
  
  <pre><code>&lt;activity android:name="TrainsActivity"&gt;
  
  &lt;/activity&gt;
  </code></pre>
  
  <p>And I'm trying to get TrainsListView:</p>
  
  <pre><code>mListView = (ListView) findViewById(R.id.TrainsListView);
  </code></pre>
  
  <p>But after this mlistView is null. Why?</p>