python - Kivy - 如何在 python 中访问 kivy 小部件？

Question

我想在 kivy 中编辑 TextInput 中的文本，但不知道如何操作，我在网上搜索时尝试过这段代码，但仍然没有成功。

class MainApp(Screen):
    def __init__(self,**kwargs):
        super(MainApp,self).__init__(**kwargs)
    pass

class Forms(BoxLayout): 
    def __init__(self, **kwargs):
        super(Main,self).__init__(**kwargs)
        self.ids.txtSearch.text = "new text"

class Main(App):
    def build(self):
        return root_widget

if __name__ == "__main__":
    Main().run()

------kivy-------

<Main>:
    TextInput:
        id: txtSearch

这不是我的全部代码，但我认为这些是问题中最重要的

这是错误:

    File "C:\Users\Guest\Documents\Python\Kivy\Project\main.py", line 295, in <module>
 ''')
 File "D:\Kivy-1.9.0-py3.4-win32-x64\kivy34\kivy\lang.py", line 1828, in load_string
 self._apply_rule(widget, parser.root, parser.root)
 File "D:\Kivy-1.9.0-py3.4-win32-x64\kivy34\kivy\lang.py", line 1985, in _apply_rule
 self.apply(child)
 File "D:\Kivy-1.9.0-py3.4-win32-x64\kivy34\kivy\lang.py", line 1872, in apply
 self._apply_rule(widget, rule, rule)
 File "D:\Kivy-1.9.0-py3.4-win32-x64\kivy34\kivy\lang.py", line 1986, in _apply_rule
 self._apply_rule(child, crule, rootrule)
 File "D:\Kivy-1.9.0-py3.4-win32-x64\kivy34\kivy\lang.py", line 1986, in _apply_rule
 self._apply_rule(child, crule, rootrule)
 File "D:\Kivy-1.9.0-py3.4-win32-x64\kivy34\kivy\lang.py", line 1983, in _apply_rule
 child = cls(__no_builder=True)
 File "C:\Users\Guest\Documents\Python\Kivy\Project\main.py", line 40, in __init__
 self.ids.txtSearch.text = "new text"
  File "kivy\properties.pyx", line 720, in kivy.properties.ObservableDict.__getattr__ (kivy\properties.c:10911)
 AttributeError: 'super' object has no attribute '__getattr__'

Answer 1

要更改 kivy 中的小部件属性，您需要在 .py 和 .kv 文件之间“链接”小部件，首先在 .py 文件中:

txt_Search = ObjectProperty()

然后在 .kv 文件中的根小部件中:

txt_Search: txtSearch

然后将 id 分配给一个小部件(就像您已经做的那样):

<Main>:
    TextInput:
        id: txtSearch
        text: ' ' 

然后在您的 .py 文件中，您可以通过执行以下操作来更改小部件的属性:

self.txt_Search.text = 'New Text'

或任何其他属性:

self.txt_Search.height = '30dp'