如何将一个属性绑定到 Kivy 中的另一个属性?
问题描述
我想将小部件的属性绑定到子小部件的属性.因此，当根小部件属性发生更改时，更改也会传播到子属性.
I want to bind a property of a widget to a property of a child widget. Thus when the root widget property is changed, the change is propagated to the child property as well.
我是这样尝试的:
self._Child._MyProperty = self._MyProperty
这可行……有时.但有时它不起作用.我不知道它什么时候起作用，为什么不起作用，在什么条件下不起作用.
This works... sometimes. But sometimes it does not work. I cannot find out when it works or why and under which conditions it does not work.
在所有情况下，我都绑定到根小部件中的方法:
In all cases I have a binding to a method in the root widget as well:
self.bind(_MyPropert = self._MyPropertyChange)
在所有情况下都会调用此方法，但有时更改不会传播到子属性.
This method is called in all cases, but sometimes the change is not propagated to the child property.
即使感觉很自然，这也不起作用:
This does not work even if it feels very natural:
self.bind(_MyProperty = self._Child._MyProperty)
但在 Kivy，我可以做到:
But in Kivy, I could do:
<RootWidget>
<ChildWidget>
_MyProperty: self.parent._MyProperty
问题是我想用 Python，而不是 Kivy.
The problem is I want to do it in Python, not in Kivy.
解决方案
要将一个属性绑定到另一个属性，您应该使用 setter 事件:
To bind one property to another you should use the setter event:
self.bind(_MyProperty=self._Child.setter('_MyProperty'))
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