Add custom widgets at runtime to screens - python-3.x

Question

I want to add Buttons (Basicly custom Buttons with Image) as a custom Widgets to "Screen1" but I always end up with "_event.pyx not found" Error.
I've tried with "super().init(**kwargs)" and without.
Python code:
sm = ScreenManager()
class DrinkWidget(Widget):
pass
class HomeScreen(BoxLayout):
def switch(self, to):
#Swithing funktion
#This is the Part, that causes the Problem I think:
class Screen1(Screen):
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.add_widget(DrinkWidget(
lable_text_optn = 'test'
))
class Screen2(Screen):
pass
class ZapfanlageApp(App):
icon = 'GUI_Elemente/app_icon.png'
title = 'Zapfanlage'
def build(self):
pass
if __name__ == "__main__":
ZapfanlageApp().run()
Kivy code (separate .kv File. The part "HomeScreen" works so far):
HomeScreen:
sm: sm
name: 'ScreenManager'
BoxLayout:
orientation: 'vertical'
rows: 2
ActionBar:
pos_hint: {'top': 1}
size_hint_y: .065
ActionView:
ActionButton:
text: 'Cocktails'
on_press:
root.switch(1)
ActionButton:
text: 'Drinks'
on_press:
root.switch(2)
ActionButton:
text: 'Einstellungen'
on_press:
root.switch(3)
ScreenManager:
id: sm
size_hint_y: .935
Screen1:
name: "screen1"
id: screen1
Screen2:
name: "screen2"
id: screen2
<Screen1#Screen>:
name: "screen_1"
id: screen1
#Here should the Buttons in GridLayout appear
<Screen2#Screen>:
name: "screen_2"
id: screen2
#This is the Custom Button I want to be inserted above
<Drink_Widget#Button>:
image_path_optn: image_path
lable_text_optn: lable_text
Button:
size_hint_x: None
size_hint_y: None
height: (root.height) -10
width: 250
on_press:
BoxLayout:
orientation: "vertical"
width: root.width
height: root.height
pos_hint: root.pos
pos: root.pos
padding: 5
Image:
source: image_path
Label:
text: label_text
I want to show a various number of DrinkWidgets on screen1 vertically and add them in runtime. But I always end up with nothing showing up or with _event.pyx not found error. Passing the code under <Screen1#Screen>: directly works.
I hope someone can help me. Thanks a lot!

Answer 1

Okay, it looks like you want to add a number of your DrinkWidgets to your screen when your app loads. First things first, in your .py file you have defined a class named Drink_widget but in .kv you call it DrinkWidget
Next, since you have your DrinkWidget defined as inheriting the Button class from kivy, you can easily change the text in the DrinkWidget using the text: field. Similarly, you can change the image that the button displays to be whatever you like using the background_normal: field. To change the image displayed when you click the button, use the background_down: field. Example:
<DrinkWidget#Button>:
text: "some text"
background_normal: "image1.png"
background_down: "image2.png"
So you don't need your lable_text_optn or image_path_optn fields.
Also, you are trying to add a number of widgets to a Screen widget, when really you should be adding a number of widgets to a Layout widget (FloatLayout, BoxLayout, or GridLayout). Your Screen widget should only have the Layout widget as its direct child.
Another issue I see is you have two root widgets inside your .kv file -- HomeScreen and BoxLayout unless your indentation is correct in the question.
Here is a minimal example of what I believe you are trying to get working:
main.py
from kivy.app import App
from kivy.uix.button import Button
class DrinkWidget(Button):
pass
class MainApp(App):
def on_start(self):
# This command is automatically called when your app loads up
the_screen_grid = self.root.ids.some_descriptive_id
# self.root refers to the root widget, which is the GridLayout
# self.root.ids gets me a DictProperty of all children widgets that have an id associated with them
# self.root.ids.some_descriptive_id gets me the GridLayout widget I defined with the id: some_descriptive_id
for i in range(3):
the_screen_grid.add_widget(DrinkWidget(text="drink " + str(i)))
MainApp().run()
main.kv
GridLayout:
cols: 1
Screen:
# Widgets that aren't Layouts normally only have 1 child widget
# To "add multiple widgets" to a screen, give the screen a Layout, then add widgets to the layout
GridLayout:
id: some_descriptive_id
rows: 1
Your code is a bit too long to give you an exact solution for your case, but I hope this example gives you the knowledge to fix it up for yourself!