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python - Kivy：滚动视图在更改小部件大小时未激活

问题描述

我正在尝试在我的用户界面中使用滚动条。我的用户界面将能够从用户输入的文本中延伸出来。但它的伸展方式不会导致 Scrollview “激活”。

这段代码只是在 4 秒后增加了小部件的大小来测试它。
首先看起来像 所有内容都显示在屏幕上的用户界面 然后看起来像 内容推送到屏幕底部的用户界面 注意我们现在看不到最后一个列表项。但是滚动条应该在屏幕右侧可见，表明我们可以向下滚动查看它。但我们不能。Scrollview 不知道内容已超出屏幕底部。

编码 

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.widget import Widget
from kivy.uix.label import Label
from kivy.clock import Clock
from kivy.uix.floatlayout import FloatLayout
from kivy.properties import ObjectProperty
from lib.modules.adaptive_grid_layout import Adaptive_GridLayout

#This should have not enough content to scroll at first,
#but the size change should push some content past the border

Builder.load_string('''
<GrowingLabel>:
    padding: 10, 5
    size_hint_y: None
    text_size: self.width, None
    group: 'test'
    canvas.before:
        Color:
            rgba: .7, .7, .7, 1
        Rectangle:
            pos: self.pos
            size: self.size

<Controller>:
    layout_content: layout_content
    BoxLayout:
        id: bl
        orientation: 'vertical'
        padding: 10, 10
        row_default_height: '48dp'
        row_force_default: True
        spacing: 10, 10
        ScrollView:
            size: self.size
            GridLayout:
                id: layout_content
                size_hint_y: None
                cols: 1
                spacing: 0, 0
                padding: 0, 0
                Adaptive_GridLayout:
                    id: Row2
                    cols: 1
                    grow_rows: True
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    GrowingLabel:
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dkdsjahf lkasjkat"
                    Label:
                        height: 20
                        text: "Lorem ipsdodo dod dodo do dodt"
                    Label:
                        height: 20
                        text: "Lorem ipsdkjwww  ww woij ksdsdf sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Lorem ipsum dolor sit amet"
                    Label:
                        height: 20
                        text: "Last List item"



''')

class GrowingLabel(Label):
    def __init__(self, **kwargs):
        super(GrowingLabel, self).__init__(**kwargs)
        #self.size_hint_y = None
        self.height = 20
        Clock.schedule_once(lambda dt: self.changeHeight(120), timeout=4)

    def changeHeight(self, p_val):
        self.height = p_val

class Controller(FloatLayout):
    layout_content=ObjectProperty(None)

    def __init__(self, **kwargs):
        super(Controller, self).__init__(**kwargs)
        self.layout_content.bind(minimum_height=self.layout_content.setter('height'))

class Nested2App(App):
    def build(self):
        return Controller()

if __name__ == '__main__':
    Nested2App().run()

注意：我正在使用一个名为 Adaptive_GridLayout 的自定义布局来处理您可以在此处找到的缩放问题。

我的问题
有没有办法手动触发滚动视图中滚动条的显示？或者有什么方法可以刷新滚动视图，以便它注意到它的内容有多大并做出适当的响应？

标签： pythonpython-3.xkivy

解决方案

下载Adaptive_GridLayout并进行我上面评论中建议的更改后：

            Adaptive_GridLayout:
                id: Row2
                cols: 1
                grow_rows: True
                size_hint: 1.0, None
                height: self.minimum_height

改后的ScrollView作品。GrowingLabelheight

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