如何解决kivy中的属性错误？答案

【问题标题】：how do i solve the attribute error in kivy?如何解决kivy中的属性错误？
【发布时间】：2023-04-02 19:28:01
【问题描述】：

嗨，我是 kivy 的新手，虽然我认为我已经放置了编码的好地方，但我遇到了很多属性错误。这是我的代码

from kivy.uix.widget import Widget
class widget_example(GridLayout):
    def button_click(self):
        print('button clicked')  
class MainWidget(Widget):
    pass
class thelabapp(App):
    pass

if __name__ == '__main__':
    thelabapp().run()

.kv 文件包含

<widget_example>:
   cls: 3
   Button:
      text:"Click here"
      on_press:root.button_click()
   Label:
      text:'Hello world'

错误出现

File "g:\project\game\kivy2\main.py", line 54, in <module>
     thelabapp().run()
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\app.py", line 
949, in run
     self._run_prepare()
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\app.py", line 
918, in _run_prepare
     self.load_kv(filename=self.kv_file)
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\app.py", line 
691, in load_kv
     root = Builder.load_file(rfilename)
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\lang\builder.py", line 306, in load_file
     return self.load_string(data, **kwargs)
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\lang\builder.p     root=widget, rule_children=rule_children)
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\uix\widget.py", line 465, in apply_class_lang_rules
     rule_children=rule_children)
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\lang\builder.py", line 543, in apply
     rule_children=rule_children)
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\lang\builder.py", line 621, in _apply_rule
     cls = Factory_get(cname)
   File "C:\Users\DELL\AppData\Local\Programs\Python\Python37\lib\site-packages\kivy\factory.py", line 145, in __getattr__
     'First letter of class name <%s> is in lowercase' % name)
 AttributeError: First letter of class name <anchorlayout> is in lowercase

提前致谢

【问题讨论】：

标签： python python-3.x kivy kivy-language

【解决方案1】：

问题是kv 期望类名大写。请参阅documentation。

所以尝试将您的 kv 更改为：

Widget_example:
<Widget_example>:
   cols: 3
   Button:
      text:"Click here"
      on_press:root.button_click()
   Label:
      text:'Hello world'

在python文件中：

from kivy.uix.widget import Widget
from kivy.uix.gridlayout import GridLayout
from kivy.app import App

class Widget_example(GridLayout):
    def button_click(self):
        print('button clicked')  
class MainWidget(Widget):
    pass
class thelabapp(App):
    pass

if __name__ == '__main__':
    thelabapp().run()

【讨论】：