On 01/-10/-28163 02:59 PM, Karim wrote:
Hello,
I implemented Observer DP on a listbox (Tkinter) as follows and I don't
understand why super() is not working and Observable.__init__(self) is
working, cf below:
class ListObservable(Listbox, Observable):
"""Creation de widget Listbox"""
def __init__(self):
super(ListObservable, self).__init__()
#Observable.__init__(self)
self._value = None
self.listeContenu = StringVar()
self.listeContenu.set(' '.join(sorted(data_base.keys())))
self.liste = Listbox(listvariable=self.listeContenu, selectmode='single')
self.liste.grid(row=0, column=1, sticky=N+S+W)
self.liste.bind('<Button-1>', self.onSelect)
_The error is:_
Traceback (most recent call last):
File "./observerAppliGraphique.py", line 118, in <module>
app=App()
File "./observerAppliGraphique.py", line 37, in __init__
self.sujet.attach(self.nom)
File "/home/karim/guiObserver/observable.py", line 11, in attach
self._observers.append(observer)
AttributeError: 'ListObservable' object has no attribute '_observers'
And the Observable class is:
class Observable(object):
"""Sujet a observer"""
def __init__(self):
self._observers = []
print('constructeur observable')
def attach(self, observer):
"""Attache un nouvel observateur"""
self._observers.append(observer)
def detach(self, observer):
"""Retire un nouvel observateur"""
self._observers.remove(observer)
def notify(self):
"""Avertit tous les observateurs que l'observable change d'etat"""
for observer in self._observers:
observer.update()
Just looking at what you supply, I'd suppose that ListBox doesn't
correctly call super() in its own __init__() method.
So I took a look at Tkinter.py, and sure enough, it just calls its own
direct parent, Widget.l
super() only works if all the classes you use are done consistently.
DaveA
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