title: ImageView selector does not work
body: <p>I am forming a tabhost like layout in my application with several ImageView. When I select on an item, the image will change. However, I tried to click on it, nothing happens! why???</p>
  
  <p>activity_main.xml</p>
  
  <pre><code>&lt;TableLayout 
      android:id="@+id/main_tab_bar"
      android:layout_width="match_parent"
      android:layout_height="0dp"
      android:layout_weight="1"
      android:stretchColumns="0,1,2,3,4"&gt;
      &lt;TableRow
          android:layout_width="match_parent"
          android:layout_height="wrap_content"&gt;
          &lt;ImageView 
              android:id="@+id/news"
              android:clickable="true"
              android:focusable="true"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/main_tab_news_selector"/&gt;
          &lt;ImageView 
              android:id="@+id/share"
              android:clickable="true"
              android:focusable="true"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/main_tab_share_selector"/&gt;
          &lt;ImageView 
              android:id="@+id/camera"
              android:clickable="true"
              android:focusable="true"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/main_tab_camera_selector"/&gt;
          &lt;ImageView 
              android:id="@+id/status"
              android:clickable="true"
              android:focusable="true"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/main_tab_status_selector"/&gt;
          &lt;ImageView 
              android:id="@+id/others"
              android:clickable="true"
              android:focusable="true"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/main_tab_others_selector"/&gt;
      &lt;/TableRow&gt;
  &lt;/TableLayout&gt;
  </code></pre>
  
  <p>main_tab_news_selector.xml (the other selectors are just similar)</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;selector xmlns:android="http://schemas.android.com/apk/res/android" &gt;
      &lt;item 
          android:drawable="@drawable/ic_action_time"
          android:state_focused="true"
          /&gt;
      &lt;item android:drawable="@drawable/ic_action_view_as_list" /&gt;
  
  &lt;/selector&gt;
  </code></pre>