CODEWITHSUNDEEP
pythonkivy
Adam Kamil
Adam Kamil

Reputation: 151

Kivy Screen not changing when button clicked python code

I have a button which was made in python file and I have been trying to make it so it changes screens from one to another.

def callback(instance):
    print("Test 1")
    sm = ScreenManager()
    sm.add_widget(ScreenTwo(name="ScreenTwo"))
    print("Test2")

class ScreenOne(Screen):
    def on_enter(self):

        self.add_widget(ImageURLButton(source=icon2, size=(100,100), size_hint=(0.1, 0.1), on_press=callback, pos_hint={"x":0.90, "top":1.0}))


class ScreenTwo(Screen):
    pass


class ScreenManagement(ScreenManager):
    pass

When I do click the button all it does it prints "Test1" and "Test2" without it changing the screen. Sorry if this is really obvious to others but I do not know how to fix it, could anyone help me please?

Upvotes: 1

Views: 641

Answers (1)

John Anderson
John Anderson

Reputation: 39092

Would be better if you posted a MCVE, but I made one myself. Here is how it can be done:

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


def callbackTo2(instance):
    sm.current="ScreenTwo"

def callbackTo1(instance):
    sm.current="ScreenOne"

class ScreenOne(Screen):
    def __init__(self, *args):
        super(ScreenOne, self).__init__(name='ScreenOne')
        self.add_widget(Button(text='Switch To Screen Two', size_hint=(0.1, 0.1), on_press=callbackTo2, pos_hint={"x":0.90, "top":1.0}))


class ScreenTwo(Screen):
    def __init__(self, *args):
        super(ScreenTwo, self).__init__(name='ScreenTwo')
        self.add_widget(Button(text='Switch To Screen One', size_hint=(0.1, 0.1), on_press=callbackTo1, pos_hint={"x":0.90, "top":1.0}))


sm = ScreenManager()
class ScreenPlayApp(App):
    def build(self):
        sm.add_widget(ScreenOne())
        sm.add_widget(ScreenTwo())
        return sm


if __name__ == '__main__':
    app = ScreenPlayApp()
    app.run()

Note that there is only one ScreenManager instance, all the screens can be added to the ScreenManager initially, and screens are switched by using sm.current=. Also, you can build your Screen in its __init__() method. Using the on_enter causes the members of the screen to be rebuilt each time the screen is displayed. Also, you cannot use both 'size' and 'size_hint' for the same widget unless you are setting 'size_hint' to 'None'.

Upvotes: 4

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