title: How to update QDataWidgetMapper items without focus
body: <p>I have several QLineEdits, each connecting to a single QStandardItemModel via their own QDataWidgetMapper, so that they all reflect the same value. </p>
  
  <p>This works great if the user inputs a value in one QLineEdit - when the QLineEdit loses focus, the model is updated and all the other QLineEdits show the same value. </p>
  
  <p>However, I want to set the values in one QLineEdit via QLineEdit::setText, and this does not do anything to make the QLineEdit lose focus. I could manually call submit on the QDataWidgetMapper, but this requires setting up access to that mapper which I'd rather avoid if I can help it, as it is in another class. </p>
  
  <p>Is there a way to set the text in the QLineEdit as if a user has entered it, for example, so that the QDataWidgetMapper will submit?</p>