如何去除 Kivy 中两个 BoxLayout 之间的空格？

Question

I state that I have already read the answers of other users to this question but none of them helped me. I'm trying to program a calculator in python with the kivy GUI interface ,he problem is that i can't remove that space highlighted in red in the attached photo down here. I have already tried with: size_hint: None,None and size:root.size[0], "5dp" to scale the BoxLayouts but it doesn't worked

         [1]: https://i.stack.imgur.com/y1ZwF.png


  BoxLayoutExample:
<BoxLayoutExample>:
    orientation: "vertical"
    Label:
        text: "0"
        font_size: "30dp"
    BoxLayout:
        orientation: "horizontal"
        Button:
            text: "7"
            size_hint: .1, .3
        Button:
            text: "4"
            size_hint: .1, .3
        Button:
            text: "1"
            size_hint: .1, .3

    BoxLayout:
        orientation: "horizontal"
        Button:
            text: ","
            size_hint: .1, .3
        Button:
            text: "0"
            size_hint: .1, .3
        Button:
            text: "="
            size_hint: .1, .3
       

Answer 1

Your problem is that you are setting size_hint of the Buttons relative to its parent BoxLayout . So in effect your BoxLayout's are taking up 1/3 of the available space (because there are three widgets in BoxLayoutExample .

Here is how to fix it:

<BoxLayoutExample>:
    orientation: "vertical"

    Label:
        text: "0"
        font_size: "30dp"
        size_hint: 1, .8

    BoxLayout:
        orientation: "horizontal"
        size_hint: 1, .1
        Button:
            text: "7"
        Button:
            text: "4"
        Button:
            text: "1"

    BoxLayout:
        orientation: "horizontal"
        size_hint: 1, .1
        Button:
            text: ","
        Button:
            text: "0"
        Button:
            text: "="

Adjust the size of the Label and the BoxLayout accordingly