title: How to make a PyQT4 window jump to the front?
body: <p>I want to make a PyQT4 window(<code>QtGui.QMainWindow</code>) jump to the front when the application received a specified message from another machine.
  Usually the window is minimized.</p>
  
  <p>I tried the <code>raise_()</code> and <code>show()</code> method but it doesn't work.</p>