当我在Python3.7上运行下拉列表程序时，Kivy立即崩溃

Question

我再次遇到kivy的一些问题每当我运行以下程序时，python会立即崩溃，打开的窗口会变为空白，我别无选择，只能关闭它。我已经尝试解决这个问题一个小时左右了，但似乎什么都做不了。

此外，我在回溯中没有错误。

提前感谢的帮助

from kivy.uix.dropdown import DropDown
from kivy.uix.button import Button
from kivy.uix.floatlayout import FloatLayout
from kivy.app import App
from os import listdir

class CustomDropDown(DropDown):
def __init__(self,**kwargs):
self.layout = FloatLayout()
self.fileList = []
def dropdown(self):
self.musDir = listdir(r'C://Users//danburnier//Desktop//PythonPrograms','r')
for file in self.musDir:
if file.endswith('.py'):
btn = Button(text=str(file[:-3]),size_hint_y=None,height=44)
btn.bind(on_release=lambda btn:self.select(btn.text))
self.add_widget(btn)
class DropDownApp(App):
def build(self):
mainButton = Button(text='Touch me.',size_hint=(None,None))
mainButton.bind(on_release=d.open)
d.bind(on_select=lambda instance, x: setattr(mainButton, 'text', x))
return CustomDropDown()
d = CustomDropDown()
if __name__ == '__main__':
DropDownApp().run()

编辑：

我不知道它是否有帮助，但在Thonny上运行它(在树莓派4上(我得到了以下回溯：

[INFO] [Logger      ] Record log in /home/pi/.kivy/logs/kivy_20-03- 
03_19.txt
[INFO] [Kivy        ] v2.0.0rc1, git-Unknown, 20200303
[INFO] [Kivy        ] Installed at "/home/pi/.local/lib/python3.7/site-
packages/kivy/__init__.py"
[INFO] [Python      ] v3.7.3 (default, Apr  3 2019, 05:39:12) 
[GCC 8.2.0]
[INFO] [Python      ] Interpreter at "/usr/bin/python3"
[INFO] [Factory     ] 184 symbols loaded
[INFO] [ImageLoaderFFPy] Using ffpyplayer 4.3.1
[INFO] [Image       ] Providers: img_tex, img_dds, img_sdl2, img_pil, 
img_ffpyplayer (img_gif ignored)
[INFO] [Window      ] Provider: sdl2
[INFO] [GL          ] Using the "OpenGL" graphics system
[INFO] [GL          ] Backend used <sdl2>
[INFO] [GL          ] OpenGL version <b'2.1 Mesa 19.2.0-rc1'>
[INFO] [GL          ] OpenGL vendor <b'Broadcom'>
[INFO] [GL          ] OpenGL renderer <b'V3D 4.2'>
[INFO] [GL          ] OpenGL parsed version: 2, 1
[INFO] [GL          ] Shading version <b'1.20'>
[INFO] [GL          ] Texture max size <4096>
[INFO] [GL          ] Texture max units <16>
[INFO] [Window      ] auto add sdl2 input provider
[INFO] [Window      ] virtual keyboard not allowed, single mode, not docked
[INFO] [Text        ] Provider: sdl2

Backend terminated or disconnected.Fatal Python error: Segmentation fault
Current thread 0xb6fccad0 (most recent call first):
File "/home/pi/.local/lib/python3.7/site-packages/kivy/core/window/__init__.py", line 1309 in add_widget
File "/home/pi/.local/lib/python3.7/site-packages/kivy/app.py", line 927 in _run_prepare
File "/home/pi/.local/lib/python3.7/site-packages/kivy/app.py", line 949 in run
File "/home/pi/Desktop/Music21/ProgFin/ScrollMenu22.py", line 34 in <module>
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 1211 in _execute_prepared_user_code
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 1139 in wrapper
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 1152 in wrapper
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 1198 in execute_source
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 840 in _execute_source
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 826 in _execute_file
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 387 in _cmd_Run
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 195 in handle_command
File "/usr/lib/python3/dist-packages/thonny/backend.py", line 137 in mainloop
File "/usr/lib/python3/dist-packages/thonny/backend_launcher.py", line 76 in <module> Use 'Stop/Restart' to restart ...

Answer 1

好吧，您的代码完全错误，充满了错误。首先，应该打开DropDown进行显示。你没有打开它。其次，你的CustomDropDown类继承了DropDown。为什么？你没有覆盖它的任何方法，你试图做什么？第三，你在那个类中有一个函数，但你没有调用它。它不会自己运行。第四，您有一些该类的对象，您对d变量中的对象做了一些操作，但随后返回了一个新的空白对象。如果你返回d，它也不会起作用，但要注意这类东西。你创建了布局，但你没有使用它。

也许这会如你所愿：

class DropDownTest(BoxLayout):
def __init__(self, **kwargs):
super(DropDownTest, self).__init__(**kwargs)
self.size_hint = (1, 1)
def createdd(self):
dropdown = DropDown()
musDir = listdir(r'C://Users//danburnier//Desktop//PythonPrograms','r')
for file in musDir:
if file.endswith('.py'):
btn = Button(text=str(file[:-3]),size_hint_y=None,height=44)
btn.bind(on_release=lambda btn: self.dropdown.select(btn.text))
self.dropdown.add_widget(btn)
mainbutton = Button(text='Open DropDown', size_hint=(1, 1), on_release=dropdown.open)
dropdown.bind(on_select=lambda instance, x: setattr(mainbutton, 'text', x))
self.add_widget(mainbutton)
class DropDownApp(App):
def build(self):
self.ddtest = DropDownTest()
self.ddtest.createdd()
return self.ddtest
if __name__ == '__main__':
DropDownApp().run()

你可以把一些东西放在函数中，但不要忘记调用它