CODEWITHSUNDEEP
pythonkivy
Yash Kolekar
Yash Kolekar

Reputation: 270

Kivy IDs needing a clock schedule

I have been trying to access the widgets in my .kv file from the python file and I have found this weird thing where if I access the IDs from the on_enter() or on_pre_enter() event from the screen, the .ids is empty and I can't access my widgets. In order to access them, I have to create another method and Clock.schedule it. Can someone explain me why this happens...

Working method

class MainScreen(Screen):

    def add_labelinputs(self, dt):
        print(self.ids)
    
    def on_enter(self):
        Clock.schedule_once(self.add_labelinputs)

Not working method (empty dict)

class MainScreen(Screen):

    def on_enter(self):
        print(self.ids)

Kivy file

#:kivy 1.11.1

WindowManager:
    MainScreen:

<MainScreen>:
    name: 'MainScreen'

    GridLayout:
        id: mainLayout
        cols: 1

Upvotes: 1

Views: 80

Answers (1)

John Anderson
John Anderson

Reputation: 39012

This is an issue with Kivy that has been around for a long time. It only affects the first Screen added to a ScreenManager in kv. A workaround is to not use kv for building the ScreenManager. Try modifying your kv to:

#:kivy 1.11.1

<MainScreen>:
    name: 'MainScreen'

    GridLayout:
        id: mainLayout
        cols: 1

And modifying your build() method to:

def build(self):
    Builder.load_string(kv)  # assumes kv string is defined as above
    sm = WindowManager()
    sm.add_widget(MainScreen())
    return sm

Upvotes: 1

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