Re: [kivy-users] Digest for kivy-users@googlegroups.com - 3 updates in 1 topic

[M H]

This has been very insightful. Thank you very much for your help.

On Fri, Nov 21, 2025, 09:38 <kivy-...@googlegroups.com> wrote:

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• missing one required positional argument error - 3 Updates

missing one required positional argument error

M H <musonda...@gmail.com>: Nov 20 12:53PM -0800 Greetings. I've been trying to make a basic checklist app with Kivy. However, I have been unable to get the new line function to work without getting an error which I assume has to do with arguments or something. I will share some of my code below. Please help out if you can.   class Shopping_List(BoxLayout): def __init__(self, **kwargs): super(Shopping_List, self).__init__(**kwargs)   self.orientation='vertical' global list_page list_page = GridLayout(cols=1, spacing=1, size_hint_y = None) list_page.bind(minimum_height=list_page.setter('height'))   scroll = ScrollView()   list_page.add_widget(Check_list_item())   scroll.add_widget(list_page) self.add_widget(scroll) #pages for shopping lists   def new_line(self, instance): item = Check_list_item(self) list_page.add_widget(item)           class Check_list_item(BoxLayout): def __init__(self,**kwargs): super(Check_list_item).__init__(**kwargs) self.orientation='horizontal' self.c_box=CheckBox(size_hint_x = None, size_hint_y=None, height = dp(25), width = dp(20)) self.text_line=TextInput(multiline=False, font_size= sp(13), text='', size_hint_x = 1, size_hint_y=None, height = dp(25)) self.text_line.bind(on_text_validate=Shopping_List.new_line(self)) self.c_button=Button(text='X', size_hint_y=None, size_hint_x=None, height = dp(25), width = dp(25))   self.add_widget(self.c_box) self.add_widget(self.text_line) self.add_widget(self.c_button)

ElliotG <elli...@cox.net>: Nov 20 01:15PM -0800 Please share a complete runnable example. It will make it easier to find the problem.   On Thursday, November 20, 2025 at 1:53:33 PM UTC-7 M H wrote:

ElliotG <elli...@cox.net>: Nov 20 02:10PM -0800 Looking at your code I can see at least one issue:   self.text_line.bind(on_text_validate=Shopping_List.new_line(self)) You want to bind to the instance of ShoppingList, not the class definition. There is an important difference between the class definition, and the instance of a class.   I put together a small example using your code as a starting point. I hope this helps. I use kv, because I find it much faster for putting together layouts. I think you can see how the ShoppingList and Item, are similar to your code. The id/ids mechanism in kivy provide a way to access widgets in the widget tree. When the kv is processed, each kv rule gets it's own ids dictionary that associates the id (the key) with the widget (the value in the ids dict).   Notice how the in ShoppingList.new_item(), the ids is used to add the item to the layout under the ScrollView. In the kv code you can see how the ids is used to call the new_item method. app.root.ids.shopping_list.new_item() app is the app root is the root widget of the app, here a BoxLayout ids is the ids dict under the root widget shoppint_list is the id that refers to the ShoppingList instance.   Here is the code. This is a complete runnable example. I hope this helps. Reach out if you have any questions.   from kivy.app import App from kivy.lang import Builder from kivy.uix.boxlayout import BoxLayout from kivy.properties import StringProperty   kv = """ <ShoppingList>: # BoxLayout orientation: 'vertical' ScrollView: do_scroll_y: True do_scroll_x: False BoxLayout: id: sl_content orientation: 'vertical' size_hint_y: None height: self.minimum_height Item: text: 'New Item'   <Item>: # BoxLayout size_hint_y: None height: '48dp' CheckBox: size_hint_x: None width: '20dp' TextInput: id: text_input multiline: False write_tab: False on_text_validate: app.root.ids.shopping_list.new_item() padding: '14sp' text: root.text Button: size_hint_x: None width: '40dp' text: 'X' on_release: root.parent.remove_widget(root)   BoxLayout: # instance the root widget orientation: 'vertical' Label: size_hint_y: None height: '30dp' text: 'Shopping List App' ShoppingList: id: shopping_list """     class ShoppingList(BoxLayout): def new_item(self): item = Item() self.ids.sl_content.add_widget(item) item.ids.text_input.focus = True     class Item(BoxLayout): text = StringProperty()     class ShoppingListApp(App): def build(self): return Builder.load_string(kv)   ShoppingListApp().run()   On Thursday, November 20, 2025 at 2:15:19 PM UTC-7 ElliotG wrote:

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