Kivy : how to get widget by id (without kv)
Solution 1
Kivy widgets make tree structure. Children of any widget are avaiable through children
atribute. If you want, you can keep reference only to root window and then iterate over it's widgets using walk
method:
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
class MyWidget(BoxLayout):
def __init__(self, **kwargs):
super().__init__(**kwargs)
button = Button(text="...", id="1")
button.bind(on_release=self.print_label)
l1 = BoxLayout(id="2")
l2 = BoxLayout(id="3")
self.add_widget(l1)
l1.add_widget(l2)
l2.add_widget(button)
def print_label(self, *args):
for widget in self.walk():
print("{} -> {}".format(widget, widget.id))
class MyApp(App):
def build(self):
return MyWidget()
if __name__ == '__main__':
MyApp().run()
walk()
and walk_reverse()
method were added to kivy.uix.widget.Widget
in 1.8.1 version of Kivy. For older versions you need to recursively parse tree yourself:
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
class MyWidget(BoxLayout):
def __init__(self, **kwargs):
super().__init__(**kwargs)
button = Button(text="...", id="1")
button.bind(on_release=self.print_label)
l1 = BoxLayout(id="2")
l2 = BoxLayout(id="3")
self.add_widget(l1)
l1.add_widget(l2)
l2.add_widget(button)
def print_label(self, *args):
children = self.children[:]
while children:
child = children.pop()
print("{} -> {}".format(child, child.id))
children.extend(child.children)
class MyApp(App):
def build(self):
return MyWidget()
if __name__ == '__main__':
MyApp().run()
Solution 2
You can retrieve the widget using directly the ids. For example in your code you can modify the Button text with the following snippet:
self.ids.2.ids.3.ids.1.text = '!!!!'
MoriB
Updated on June 17, 2022Comments
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MoriB almost 2 years
Let's say I define on the fly in Kivy a few widgets (buttons) and dynamically assign their id. I'm not using kv language in this use case. I can keep a reference of a widget id without keeping track of the widget itself : then I'd like to access the widget through its id. Can I do something like "get widget by id" ? (If I had defined the widget in a kv file, I could have used self.ids.the_widget_id to access the widget itself through its id)
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scicalculator over 7 yearsAs someone new to kivy, I would like to know further why this answer was downvoted. Is this because in general, the program should only locally know about the widgets it needs to know about, or is it because
self
is more akin toroot
in this example. Any further details?