hlist_view_demo.py

from traits.api import (HasTraits, Instance, Int, List, Property, Unicode,
                        on_trait_change)
from traitsui.api import HGroup, ModelView, UItem, View

COLUMNS_WIDTH = 200


class Case(HasTraits):
    param1 = Unicode
    param2 = Unicode
    param3 = Unicode
    param4 = Unicode
    param5 = Unicode
    param6 = Unicode
    param7 = Unicode


class CaseView(ModelView):
    traits_view = View(
        'model.param1',
        'model.param2',
        'model.param3',
        'model.param4',
        'model.param5',
        'model.param6',
        'model.param7',
    )


class Cases(HasTraits):
    cases = List(Instance(Case))


class CasesView(ModelView):
    model = Instance(Cases)
    num_cases = Property(Int)
    case_view_0 = Instance(CaseView, depends_on='model.cases')
    case_view_1 = Instance(CaseView, depends_on='model.cases')
    case_view_2 = Instance(CaseView, depends_on='model.cases')

    traits_view = View(
        HGroup(
            UItem(
                'case_view_0', style='custom', visible_when='num_cases > 0',
                width=COLUMNS_WIDTH
            ),
            UItem(
                'case_view_1', style='custom', visible_when='num_cases > 1',
                width=COLUMNS_WIDTH
            ),
            UItem(
                'case_view_2', style='custom', visible_when='num_cases > 2',
                width=COLUMNS_WIDTH
            ),
        ),
        scrollable=True,
        resizable=True,
    )

    def _get_num_cases(self):
        return len(self.model.cases)

    @on_trait_change('model')
    def set_views(self):
        if len(self.model.cases) > 0:
            self.case_view_0 = CaseView(model=self.model.cases[0])
        if len(self.model.cases) > 1:
            self.case_view_1 = CaseView(model=self.model.cases[1])
        if len(self.model.cases) > 2:
            self.case_view_2 = CaseView(model=self.model.cases[2])


# CaseView(model=Case()).configure_traits()
CasesView(model=Cases(cases=[Case(), Case(), Case()])).configure_traits()