title: Implementing QProgressBar against a class
body: <p>My PyQt program has 2 widgets (selecting files etc) and then a Main Window which displays the results of the parsed files.</p>
  
  <p>The program works great for small sample files, but when trying to parse larger files it will hang (display "Not Responding") and then show the results after about 30 seconds or so.</p>
  
  <p>I would like to implement a QDialog before the Main Window opens. The QDialog will have a progress bar to let the user know when the Main Window will open.</p>
  
  <p>This progress bar needs to be set to the length of time before the Main Window pops up.</p>
  
  <p>What is the best way to implement this? I have seen some examples, but the progress bar is just set to a standardised time, not when the processing(parsing) is complete.</p>
  
  <p>I currently have the following code which opens the Main Window.</p>
  
  <pre><code>def openWidgetMain(self):
          self.WidgetMain = WidgetMain()
          self.WidgetMain.show()
          self.close()
  </code></pre>
  
  <p>All the processing for this window is done when it opens. So how do I connect the QProgressBar?</p>