Kivy Python TextInput display Bubble

I am trying to display numeric keyboard in bubble for TextInput in Kivy. Is it possible? So far I have:

Builder.load_string('''
<NumericKeyboard>
size_hint: (None, None)
size: (160, 120)
pos_hint: {'center_x': .5, 'y': .6}
BubbleButton:
    text: 'Cut'
BubbleButton:
    text: 'Copy'
BubbleButton:
    text: 'Paste'
''')

class NumericKeyboard(Bubble):
    pass

class CustomTextInput(TextInput):
def __init__(self, **kwargs):
    super(CustomTextInput, self).__init__(**kwargs)

def on_focus(self, instance, value):
    self.bubb = NumericKeyboard()
    self.add_widget(self.bubb)

But the bubble will not display.

Answer

Yes, it is possible to display numeric key pad using Kivy Bubble for TextInput widget. Please refer to the example below for details.

Note: The text input is not filtered.

Example

main.py

from kivy.app import App
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.bubble import Bubble, BubbleButton
from kivy.uix.label import Label
from kivy.properties import ObjectProperty
from kivy.lang import Builder


class CustomBubbleButton(BubbleButton):
    pass


class NumericKeyboard(Bubble):
    layout = ObjectProperty(None)

    def __init__(self, **kwargs):
        super(NumericKeyboard, self).__init__(**kwargs)
        self.create_bubble_button()

    def create_bubble_button(self):
        numeric_keypad = ['7', '8', '9', '4', '5', '6', '1', '2', '3', '', '0', '.']
        for x in numeric_keypad:
            if len(x) == 0:
                self.layout.add_widget(Label(text=""))
            else:
                bubb_btn = CustomBubbleButton(text=str(x))
                self.layout.add_widget(bubb_btn)


class BubbleShowcase(FloatLayout):
    text_input = ObjectProperty(None)

    def show_bubble(self, *l):
        if not hasattr(self, 'bubb'):
            self.bubb = bubb = NumericKeyboard()
            self.bubb.arrow_pos = "bottom_mid"
            self.add_widget(bubb)


Builder.load_file("test.kv")


class TestBubbleApp(App):
    title = "Numeric Key Pad - Using Bubble"

    def build(self):
        return BubbleShowcase()


if __name__ == '__main__':
    TestBubbleApp().run()

test.kv

#:kivy 1.10.0

<CustomBubbleButton>:
    on_release:
        app.root.text_input.text += self.text


<NumericKeyboard>:
    layout: layout

    size_hint: (None, None)
    size: (160, 120)
    pos_hint: {'center_x': .5, 'y': .6}

    GridLayout:
        id: layout
        cols: 3

<BubbleShowcase>:
    text_input: text_input

    canvas:
        Color:
            rgba: 0, 1, 1, 1
        Rectangle:
            size: self.width, self.height
    TextInput:
        id: text_input
        pos_hint: {'center_x': .5, 'y': .54}
        size_hint: (0.2, 0.06)
        cursor_blink: True
        font_size: 20
        multiline: False
        on_focus:
            root.show_bubble()

Output

Figure 1 - App Startup Figure 2 - Bubble Numeric Key Pad on_focus TextInput Figure 3 - Pressed Digit 3 Figure 4 - Pressed Decimal Point Figure 5 - Pressed Digits 1, 4, `, 5, and 9