title: switching layouts in Qt
body: <p>I have 2 layouts - <code>layout1</code> and <code>layout2</code>. Let's say both are entirely different in terms of number of types of widget in them. Now I have 2 buttons <code>but1</code> and <code>but2</code>. When <code>but1</code> is cliked <code>layout1</code> is activated and when <code>but2</code> is clicked <code>layout2</code> is activated. 
  How can I achieve this in Qt? </p>
  
  <p><strong>Note:</strong>
  I don't want to delete my widgets( or layouts) </p>