Kivy ids in python code

Question

main:

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.boxlayout import BoxLayo         


        

Answer 1

from functools import partial

To access the textinput in your external method, you could use partial functions or lambda function.

self.ids

You are getting None or empty dictionary because you don't have a kv file.

Note

When your kv file is parsed, kivy collects all the widgets tagged with id’s and places them in this self.ids dictionary type property.

Please refer to my example below for deatils.

Example

main.py

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput
from functools import partial


class testclass:
    def someth(*args, txt):
        print(txt)


class BeginScreen(Screen):
    def __init__(self, **kwargs):
        super(BeginScreen, self).__init__(**kwargs)
        layout = BoxLayout(orientation='vertical', padding=20, spacing=5)
        layout.add_widget(Label(text=str('Hello')))
        layout.add_widget(TextInput(id='test', text=''))
        layout.add_widget(Button(text='Button!', on_press=partial(testclass.someth, txt='?')))
        self.add_widget(layout)
        print("self.ids={}".format(self.ids))


class TestApp(App):
    from kivy.config import Config
    Config.set('graphics', 'width', '800')
    Config.set('graphics', 'height', '400')

    def build(self):
        sm = ScreenManager()
        sm.add_widget(BeginScreen(name='test'))
        return sm

TestApp().run()

Output