title: How does Grid View change column number runtime?
body: <p>I am trying to change gridView column number. I call <code>setNumColumn()</code> and <code>invalidateViews()</code> to update the view.</p>
  
  <p>However, the grid's cell width will not change dynamically. I set the <code>stretchMode="columnWidth"</code>, but it didn't work.</p>
  
  <p><img src="https://i.stack.imgur.com/4u4Ow.jpg" alt="screenshot"></p>