title: QLineEdit is not updating with setText
body: <p>I have a program with two windows, main and the settings.<br/>
  When I run setText on a QLineEdit in the settings.py file, the new string is not in the GUI, and I can see the string before the setText code.<br/>
  When I put the same code in the settingsUI file generated from Qt Designer, It works. But in the settings.py doesn't.<br/>
  The settings file is the file that contains the SettingsWindow class and I can put the real python code in it.<br/>
  The settingsUI file is the file that contains the GUI, I generated it with pyuic4 (or pyuic5).<br/>
  This code works in settingsUI file:<br/><br/>
      <code>self.browse_file.setText("safa")</code><br/><br/>
  But dosen't work in settings file.</p>
  
  <p>--UPDATE--</p>
  
  <pre><code>import sys
  from PyQt4 import QtCore, QtGui
  from settingsui import Ui_Dialog
  class SettingsWindow(QtGui.QDialog, Ui_Dialog):
      def __init__(self):
          QtGui.QDialog.__init__(self)
          Ui_Dialog.__init__(self)
          self.setupUi(self)
          self.lineEdit.setText("safa")
          print self.lineEdit.text()
  </code></pre>
  
  <p>After: <code>self.lineEdit.setText("safa")</code> , I can't see any text in the QLineEdit.<br/>
  <code>print self.lineEdit.text()</code> outputs the text "safa"</p>