kv 文件中的 Err0r

Question

为什么不起作用？：

from kivy.lang import Builder
from kivymd.app import MDApp
KV = '''
Screen:
    MDFlatButton:
        id: flat
        text: root.gg
'''
class Test(MDApp):
    def build(self):
        gg = '123'
        return Builder.load_string(KV)
Test().run()

错误：

Traceback (most recent call last):
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 242, in create_handler
     return eval(value, idmap), bound_list
   File "<string>", line 5, in <module>
   File "kivy\weakproxy.pyx", line 32, in kivy.weakproxy.WeakProxy.__getattr__
 AttributeError: 'Screen' object has no attribute 'gg'
 
 During handling of the above exception, another exception occurred:
 
 Traceback (most recent call last):
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 695, in _apply_rule
     value, bound = create_handler(
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 245, in create_handler
     raise BuilderException(rule.ctx, rule.line,
 kivy.lang.builder.BuilderException: Parser: File "<inline>", line 5:
 ...
       3:    MDFlatButton:
       4:        id: flat
 >>    5:        text: root.gg
 ...
 AttributeError: 'Screen' object has no attribute 'gg'
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 242, in create_handler
     return eval(value, idmap), bound_list
   File "<string>", line 5, in <module>
   File "kivy\weakproxy.pyx", line 32, in kivy.weakproxy.WeakProxy.__getattr__
 
 
 During handling of the above exception, another exception occurred:
 
 Traceback (most recent call last):
   File "C:\Users\lolo\PycharmProjects\FindWord\FindWord.py", line 14, in <module>
     Test().run()
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\app.py", line 949, in run
     self._run_prepare()
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\app.py", line 919, in _run_prepare
     root = self.build()
   File "C:\Users\lolo\PycharmProjects\FindWord\FindWord.py", line 13, in build
     return Builder.load_string(KV)
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 408, in load_string
     self._apply_rule(
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 710, in _apply_rule
     raise BuilderException(rule.ctx, rule.line,
 kivy.lang.builder.BuilderException: Parser: File "<inline>", line 5:
 ...
       3:    MDFlatButton:
       4:        id: flat
 >>    5:        text: root.gg
 ...
 BuilderException: Parser: File "<inline>", line 5:
 ...
       3:    MDFlatButton:
       4:        id: flat
 >>    5:        text: root.gg
 ...
 AttributeError: 'Screen' object has no attribute 'gg'
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 242, in create_handler
     return eval(value, idmap), bound_list
   File "<string>", line 5, in <module>
   File "kivy\weakproxy.pyx", line 32, in kivy.weakproxy.WeakProxy.__getattr__
 
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 695, in _apply_rule
     value, bound = create_handler(
   File "C:\Users\lolo\PycharmProjects\FindWord\venv\lib\site-packages\kivy\lang\builder.py", line 245, in create_handler
     raise BuilderException(rule.ctx, rule.line,

我需要 kv 文件来查看函数内部的变量。每个人都建议使用root，但这个错误阻止了我。 我需要完全使用'root.gg'，应用程序不适合，因为当需要引用函数中的变量时应用程序不起作用。问题的上一版本here

看起来您的帖子主要是代码；请添加更多详细信息。

看起来您的帖子主要是代码；请添加更多详细信息。

看起来您的帖子主要是代码；请添加更多详细信息。

Answer 1

您需要在类级别声明 gg。 另外，不要使用root.gg，而是使用app.gg