views on Nested HasTraits object

Question

I am having trouble getting the views to work as expected, using nested HasTraits. For example:

class A(HasTraits):
    b= Any()

...
view = View(...
    Item('b', style='custom')
...

I would like to import the class of b and assign it to A,

from some_other_mod import B 
# B HasTraits also
a = A(b = B())

This works, but the view of B() does not display within a, when i a.configure_traits()

(Note this is related, but not identical to this post)

Answer 1

You need to use an InstanceEditor.

class A(HasTraits):
    b = Instance(HasTraits)
    traits_view = View( Item('b', editor=InstanceEditor(), style='custom') )

class B(HasTraits):
    c = Int
    traits_view = View( Item('c') )

Note that an Instance trait uses an InstanceEditor by default. An Any trait by default uses a TextEditor instead.