title: gridview clicking effect
body: <p>I have a gridview</p>
  
  <pre><code>&lt;GridView
      android:id="@+id/gridview"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_centerVertical="true"
      android:layout_marginLeft="60px"
      android:layout_marginRight="60px"
      android:background="#343434"
      android:listSelector="#00343434"
      android:numColumns="2"
      android:verticalSpacing="25px" &gt;
  &lt;/GridView&gt;
  </code></pre>
  
  <p>When i click, a grey color box will indicate the item being clicked.</p>
  
  <p>I want to remove the grey color box effect when click an item. </p>
  
  <p>Please give some suggestion, thanks.</p>