title: Lock/keep focus on input element?
body: <p>I'm using a QLineEdit field within a touch-controlled environment, that's why my question is a bit strange. There is a situation where a user may have typed some illegal data into the QLineEdit input field and should not be allowed to leave this input field until the illegal input has been corrected.</p>
  
  <p>Now when I check the focus-lost-event for the QLineEdit, it is too late. This event is sent when e.g. an other button is clicked but this button is already processed at this point, and the probably wrong data in my input field are used.</p>
  
  <p>So how can I solve this? Is there a possibility to lock the focus on an element so that all other widgets can't be used until this lock is released (disabling all the other widgets is NOT a solution)?</p>
  
  <p>Or is there some kind of pre-focus-event where I can inhibit the event to the other widget and keep my input field active and focused exclusively?</p>
  
  <p>Thanks!</p>