CODEWITHSUNDEEP
pythonpython-3.xkivy
Logan Richardson
Logan Richardson

Reputation: 3

How to set ID of dynamic TextInput in Kivy

Very simple question I might just not be comprehending life, 

self.ids.UpdateCustomer1.add_widget(TextInput(text='123',id=str('AddUserTextBox')))

Here is my code, I just want to set the id of a dynamic text box that pops up when a button is pressed. that all works fine, but whenever I reference AddUserTextBox.text it tells me its non-existent. or more specifically " NameError: name 'AddUserTextBox' is not defined"

Now I have tried setting id='AddUserTextBox' and also as id=AddUserTextBox and I have had no luck. all help would be greatly appreciated

Upvotes: 0

Views: 3291

Answers (2)

ikolim
ikolim

Reputation: 16041

Problem

You cannot reference by using self.ids.AddUserTextBox.text or self.ids['AddUserTextBox'].text because the id created in Python code is not the same as id defined in kv file. The differences are as follow:

  1. Python code: The value assigned to id is a string and it is not stored in self.ids dictionary.
  2. kv file: The value assigned to id is a string and it is stored in self.ids dictionary.

Kv language » Referencing Widgets

Warning

When assigning a value to id, remember that the value isn’t a string. There are no quotes: good -> id: value, bad -> id: 'value'

Kv language » Accessing Widgets defined inside Kv lang in your python code

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.

Solution

Please refer to snippets, example, and output for details.

  1. Instantiate a TextInput widget and assign it to self.AddUserTextBox
  2. Add self.AddUserTextBox widget to self.ids.UpdateCustomer1
  3. Referencing TextInput's text by self.AddUserTextBox.text or root.AddUserTextBox.text. Depending on where it was created.

Snippets

self.AddUserTextBox = TextInput(text='123')
self.ids.UpdateCustomer1.add_widget(self.AddUserTextBox)
...
print(self.AddUserTextBox.text)

Example

main.py

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput


class RootWidget(BoxLayout):

    def add_user_text(self):
        self.AddUserTextBox = TextInput(text='123')
        self.ids.UpdateCustomer1.add_widget(self.AddUserTextBox)
        print(self.AddUserTextBox.text)


class TestApp(App):

    def build(self):
        return RootWidget()


if __name__ == "__main__":
    TestApp().run()

test.kv

#:kivy 1.11.0

<RootWidget>:
    orientation: 'vertical'
    Button:
        size_hint: 1, 0.2
        text: 'Add User TextInput'
        on_release:
            root.add_user_text()

    GridLayout:
        id: UpdateCustomer1
        rows: 1

Output

Img01 Img02

Upvotes: 1

John Anderson
John Anderson

Reputation: 39152

The ids are setup when your .kv file (or string) is first processed and is not updated after that. So your new TextInput widget id does not get added to the ids. You can work around that by doing:

import weakref
textinput = TextInput(text='123')
self.ids.UpdateCustomer1.add_widget(textinput)
self.ids['AddUserTextBox'] = weakref.ref(textinput)

The weakref is used because that is what kivy uses when it initially sets up the ids dictionary. This is not the best way to do it. It would be better just to keep a reference to your added TextInput.

Upvotes: 3

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