Dynamically adding a trait with UI update

Question

Is it possible in a configure_traits() window to have a button like 'Add integer' on which clicking will add a new integer field ready for edition in the same window?

Do you want to be able to add an indeterminate number of such dynamically fields, or would it work to simply have some hidden fields that would be made visible when you clicked the button? — Jonathan March, Jul 07 '16 at 22:36

score 0 · Accepted Answer · answered Jul 08 '16 at 15:16

As @jonathan-march points out, it would probably be safest if you only need a fixed number of fields to keep them hidden until you clicked the button, but if you need an indeterminate number, it's fairly trivial to make a List of Ints and then append to that list each time you click the button. The trouble will be in the book-keeping that comes with keeping track of the indices of those list elements when you want to listen to them. I whipped up a small example of how you might do this below:

from traits.api import Button, HasStrictTraits, Int, List
from traitsui.api import Group, Item, ListEditor, UItem, View


class DynamicListOfInts(HasStrictTraits):

    integer_list = List(Int)
    add_int = Button('Add integer')

    def default_traits_view(self):
        view = View(
            Group(
                UItem('add_int'),
                Item('integer_list', editor=ListEditor()),
            ),
            width=300,
            height=500,
        )
        return view

    def _add_int_changed(self):
        self.integer_list.append(0)


if __name__ == '__main__':
    list_of_ints = DynamicListOfInts()
    list_of_ints.configure_traits()

Dynamically adding a trait with UI update

1 Answers1