我有一个CustomDropDown小部件网格，每次都不能以相同的方式工作。但每次我都会遇到这个常见错误：
ReferenceError: weakly-referenced object no longer exists
我的python代码如下：
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.uix.dropdown import DropDown
from kivy.lang import Builder
from kivy.uix.relativelayout import RelativeLayout
Mess = {
'mess1': 'RR - SI',
'mess2': 'VTH - SI',
'mess3': 'SK - SI',
'mess4': 'CV - SI',
'mess5': 'CR - NI',
'mess6': 'AD - NI',
'mess7': 'MD - NI',
'mess8': 'MDJ - NI',
'mess9': 'FC - HM'
}
Builder.load_string('''
<ChoiceLayout>
orientation:'vertical'
Label:
text: "Mess Registration for Jul-Nov 2016"
size_hint: (None,None)
font_size:'48dp'
size_hint_y:1
pos_hint: {'center_x': .5}
BoxLayout:
orientation:'horizontal'
size_hint_y:2
Label:
text: 'NAME : {}'.format('MyName')
size_hint: (None,None)
font_size:'36dp'
pos_hint: {'left': 1}
Label:
text: 'ROLL NUMBER : {}'.format('CS22A565')
size_hint: (None,None)
font_size:'36dp'
pos_hint: {'right': 1}
BoxLayout:
orientation:'vertical'
size_hint_y: 4
BoxLayout:
orientation:'horizontal'
CustomDropDown:
id: dropdown1
CustomDropDown:
id: dropdown2
CustomDropDown:
id: dropdown3
BoxLayout:
orientation:'horizontal'
CustomDropDown:
id: dropdown4
CustomDropDown:
id: dropdown5
CustomDropDown:
id: dropdown6
BoxLayout:
orientation:'horizontal'
CustomDropDown:
id: dropdown7
CustomDropDown:
id: dropdown8
CustomDropDown:
id: dropdown9
Button:
text: 'Submit'
<CustomDropDown>
orientation:'vertical'
Button:
id: btn
text:'click me'
on_release: dropdown.open(self)
size_hint_y: None
height: '24dp'
DropDown:
id: dropdown
on_parent: self.dismiss()
on_select: btn.text= '{}'.format(args[1])
size_hint_y: None
height: '24dp'
''')
class ChoiceLayout(BoxLayout):
pass
class CustomDropDown(BoxLayout):
def build(self):
tempMess = Mess
for mess,mname in tempMess:
mBtn = Button(text = mname,on_release = self.dropdown.select(mess))
self.dropdown.add_widget(mBtn)
del tempMess[mess]
def selected(args):
self.ids['btn'].text='{}'.format(args)
class RegisterApp(App):
def build(self):
return ChoiceLayout()
if __name__ == '__main__':
RegisterApp().run()
所以，我可能想做的事情是：
控制台中的日志是：
Traceback (most recent call last):
File "prog.py", line 100, in <module>
RegisterApp().run()
File "/usr/lib/python2.7/dist-packages/kivy/app.py", line 828, in run
runTouchApp()
File "/usr/lib/python2.7/dist-packages/kivy/base.py", line 487, in runTouchApp
EventLoop.window.mainloop()
File "/usr/lib/python2.7/dist-packages/kivy/core/window/window_sdl2.py", line 619, in mainloop
self._mainloop()
File "/usr/lib/python2.7/dist-packages/kivy/core/window/window_sdl2.py", line 362, in _mainloop
EventLoop.idle()
File "/usr/lib/python2.7/dist-packages/kivy/base.py", line 330, in idle
self.dispatch_input()
File "/usr/lib/python2.7/dist-packages/kivy/base.py", line 315, in dispatch_input
post_dispatch_input(*pop(0))
File "/usr/lib/python2.7/dist-packages/kivy/base.py", line 281, in post_dispatch_input
wid.dispatch('on_touch_up', me)
File "kivy/_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy/_event.c:7699)
File "/usr/lib/python2.7/dist-packages/kivy/uix/behaviors/button.py", line 138, in on_touch_up
self.dispatch('on_release')
File "kivy/_event.pyx", line 714, in kivy._event.EventDispatcher.dispatch (kivy/_event.c:7654)
File "kivy/_event.pyx", line 1224, in kivy._event.EventObservers.dispatch (kivy/_event.c:13497)
File "kivy/_event.pyx", line 1108, in kivy._event.EventObservers._dispatch (kivy/_event.c:12329)
File "/usr/lib/python2.7/dist-packages/kivy/lang.py", line 1557, in custom_callback
exec(__kvlang__.co_value, idmap)
File "<string>", line 57, in <module>
File "kivy/weakproxy.pyx", line 19, in kivy.weakproxy.WeakProxy.__getattr__ (kivy/weakproxy.c:1143)
File "kivy/weakproxy.pyx", line 15, in kivy.weakproxy.WeakProxy.__ref__ (kivy/weakproxy.c:1042)
ReferenceError: weakly-referenced object no longer exists