Kivy \\ 如何将按钮绑定到 boxlayout 的底部

Question

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.core.window import Window
from kivy.uix.scrollview import ScrollView
from kivy.effects.scroll import ScrollEffect
from kivy.uix.widget import Widget
from kivy.uix.button import Button


class BSGameMain(BoxLayout):
    blmain = BoxLayout(orientation = 'vertical') # MainBoxLayout init

    scrlFBtns = ScrollView(effect_cls = 'ScrollEffect')

    blbtns = BoxLayout(
        orientation = 'vertical',
        size_hint_y = None
        ) # BoxLayout for buttons

    blbtns.bind(minimum_height = blbtns.setter('height'))
    scrlFBtns.add_widget(blbtns)

    for i in range (2):
        blbtns.add_widget(Button(
            text='asd',
            size_hint_y = None,
            height = 40
            ))

    lblmain = Label(text = 'asd')
    blmain.add_widget(lblmain)
    blmain.add_widget(scrlFBtns)


class BSApp(App):
    def build(self):
        game = BSGameMain()
        return game.blmain

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

考虑到滚动视图，有必要使按钮从下方出现，而不是从中间出现。我就是做不到。

Answer 1

请记住，BoxLayouts 会覆盖对定位的修改，因为它们会自动定位其子项。这使他们非常自给自足，但有点固执。

就像你说的，如果只有几个按钮，它会粘在中间。 scrollview 有效，但由于它是 boxlayout 的子项，它只能伸展到 boxlayout 规定的范围，即 window 的下半部分。此外，由于按钮的框布局自上而下添加子项，这就是您的按钮出现在中间的原因。实际上，它是在 window.

的 下半部分 顶部添加按钮

您指定了不需要boxlayouts的boxlayouts。您可能想要的一件事是根据滚动视图中的按钮数量随意定位滚动视图。这将需要一个 if 语句和一个整数。

我的改动：

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.core.window import Window
from kivy.uix.scrollview import ScrollView
from kivy.effects.scroll import ScrollEffect
from kivy.uix.widget import Widget
from kivy.uix.button import Button

class BSGameMain(): #No longer a boxlayout.
    scroll_height = 0;
    blmain = Widget() #No longer a boxlayout. Fills the window.

    blbtns = BoxLayout(
        orientation = 'vertical',
        size_hint = (1, None),
        ) # BoxLayout for buttons

    blbtns.bind(minimum_height = blbtns.setter('height'))

    for i in range (20):     #number of buttons printed
        blbtns.add_widget(Button(
            text='asd',
            size_hint_y = None,
            height = 40
            ))
        if (scroll_height < (Window.height / 2)):
            scroll_height = scroll_height + 40      #This measures how much space we need for the scrollview. Make sure it matches button height!

    scrlFBtns = ScrollView(effect_cls = 'ScrollEffect', pos = (0, 0), size = (Window.width, scroll_height)) 
    #The pos of 0,0 ensures scrlFBtns stays at the bottom. Place at negative coordinates if you want it to extend off-screen.
    scrlFBtns.add_widget(blbtns)
    lblmain = Label(text = 'asd', halign = 'center', y = (Window.height * 0.75), width = Window.width, color = (1,1,1,1))

    blmain.add_widget(lblmain)
    blmain.add_widget(scrlFBtns)

class BSApp(App):
    def build(self):
        game = BSGameMain()
        return game.blmain

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

结果：

一键

,

三个按钮

,

二十个按钮

希望这符合您的要求！

Kivy \\ 如何将按钮绑定到 boxlayout 的底部

Kivy \\ How to tie a button to the bottom of the boxlayout

python

button

scrollview

boxlayout

kivy