Preventing default behavior in a viewstack?

Question

I've got a component with a handler like:
public function choiceHandler():void {
if (everythingOK) { processData(); }
else { showAlert(_msg5,_ttl5); }
I'm calling this handler from the viewStack, using the "hide"
event for this component's instance since I want it handled when
the user leaves the screen.
However, if the alert fires (the "else" clause) the viewstack
has already gone to another child.
How can I "catch" that error and not have the viewstack leave
that page? Or is there a better way to do this?

Answer 1

I'm not sure if this will work, but include an event argument
in your choiceHandler and if the else clause executes, then do
event.preventDefault() which *may* tell the ViewStack not to switch
children.
Otherwise you may need to extend the ViewStack and check the
docs to see what protected functions it has that you can override
and alter its behavior.