CODEWITHSUNDEEP
pythonpropertieskivy
CountVonCount
CountVonCount

Reputation: 85

How can I bind a property to another property in Kivy?

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.

I tried it this way:

self._Child._MyProperty = self._MyProperty

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.

In all cases I have a binding to a method in the root widget as well:

self.bind(_MyPropert = self._MyPropertyChange)

This method is called in all cases, but sometimes the change is not propagated to the child property.

This does not work even if it feels very natural:

self.bind(_MyProperty = self._Child._MyProperty)

But in Kivy, I could do:

<RootWidget>
    <ChildWidget>
        _MyProperty: self.parent._MyProperty

The problem is I want to do it in Python, not in Kivy.

Upvotes: 3

Views: 3037

Answers (1)

Mikhail Gerasimov
Mikhail Gerasimov

Reputation: 39516

To bind one property to another you should use the setter event:

self.bind(_MyProperty=self._Child.setter('_MyProperty'))

Upvotes: 4

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