Kivy 网格布局的 minimum_height 为 0

Question

所以我是 kivy 的新手，我正在尝试使按钮列表可滚动。问题是我无法让滚动视图工作，然后我偶然发现了Kivy ScrollView - Not Scrolling。当我将它添加到我的代码中时，它仍然无法正常工作。然后我尝试打印 minimum_height 并且无论有多少按钮它总是打印 0...

这是代码（确实写得很糟糕，但这只是为了测试目的，我可能会在管理滚动时重写它）：

    def on_pre_enter(self, *args):
        mainLayout = RelativeLayout()
        self.add_widget(mainLayout)
        scroll = ScrollView(do_scroll_x = False)
        infoLayout = GridLayout(cols = 1, size_hint = (0.5, None), pos_hint={"top":0.8,"center_x":0.5})
        mainLayout.add_widget(scroll)
        scroll.add_widget(infoLayout)

        InfoWidgetButton = Button(text='Hello world', font_size=14, size_hint=(0.5, None), height = 30, pos_hint={"top":0.8,"center_x":0.5}, on_release= lambda x:self.buttonPress(infoLayout))
        infoLayout.add_widget(InfoWidgetButton)
        InfoWidgetButton = Button(text='Hello world', font_size=14, size_hint=(0.5, None), height=30,
                                  pos_hint={"top": 0.8, "center_x": 0.5},
                                  on_release=lambda x: self.buttonPress(infoLayout))
        infoLayout.add_widget(InfoWidgetButton)
        InfoWidgetButton = Button(text='Hello world', font_size=14, size_hint=(0.5, None), height=30,
                                  pos_hint={"top": 0.8, "center_x": 0.5},
                                  on_release=lambda x: self.buttonPress(infoLayout))
        infoLayout.add_widget(InfoWidgetButton)
        InfoWidgetButton = Button(text='Hello world', font_size=14, size_hint=(0.5, None), height=30,
                                  pos_hint={"top": 0.8, "center_x": 0.5},
                                  on_release=lambda x: self.buttonPress(infoLayout))
        infoLayout.add_widget(InfoWidgetButton)
        InfoWidgetButton = Button(text='Hello world', font_size=14, size_hint=(0.5, None), height=30,
                                  pos_hint={"top": 0.8, "center_x": 0.5},
                                  on_release=lambda x: self.buttonPress(infoLayout))
        infoLayout.add_widget(InfoWidgetButton)
        InfoWidgetButton = Button(text='Hello world', font_size=14, size_hint=(0.5, None), height=30,
                                  pos_hint={"top": 0.8, "center_x": 0.5},
                                  on_release=lambda x: self.buttonPress(infoLayout))
        infoLayout.add_widget(InfoWidgetButton)
        InfoWidgetButton = Button(text='Hello world', font_size=14, size_hint=(0.5, None), height=30,
                                  pos_hint={"top": 0.8, "center_x": 0.5},
                                  on_release=lambda x: self.buttonPress(infoLayout))
        infoLayout.add_widget(InfoWidgetButton)
        infoLayout.height = infoLayout.minimum_height
        print(infoLayout.minimum_height)

Answer 1

一个人在 reddit 上回答了我的问题： https://www.reddit.com/r/kivy/comments/irats0/kivy_grid_layouts_minimum_height_is_0/