QDialog not painting in loop

QDialog not painting in loop

So I have a QDialog class that's launched from a QMainWindow. The
constructor sets up the UI. I declare the object in the QMainWindow, then
i call the method that loops in the QDialog class. The result is that when
the QDialog is shown(dialog->show() is in the constructor) the window
appears without the layout. After the loop completes the layout is then
shown.
I've tried using exec() instead, but then the method does not execute
until after the dialog is closed.