python - Saving a kivy widget to a file

Question

So I'm trying to save a kivy widget to a file using cpickle and I get an error.

from kivy.uix.widget import Widget
import cPickle as pickle

foo = Widget()
bar = open('bar.dat', 'w')
pickle.dump(foo, bar)
bar.close()

Gives Traceback like,

Traceback (most recent call last):
  File ".last_tmp.py", line 6, in <module>
    pickle.dump(foo, bar)
  File "QPython/build/python-install/lib/python2.7/copy_reg.py", line 71, in_reduce_ex
TypeError: __init__() takes exactly 0 positional arguments(1 given)

Is there a way to fix this? Or is there a better way to save a widget to a file for later use?

Answer 1

Looks like using higher protocol may help:

#!/usr/bin/python
# -*- coding: utf-8 -*-

try:
    import cPickle as pickle
except:
    import pickle

from kivy.uix.widget import Widget

w = Widget()
w.test = 5
data_string = pickle.dumps(w, protocol=pickle.HIGHEST_PROTOCOL)

x = pickle.loads(data_string)
print x.test