ScrollView 小部件在 kivy 中不滚动

2022-01-15 00:00:00 python kivy

问题描述

我在尝试使动态生成的标签堆栈可滚动时遇到一些问题.我可能误解了应该使用 ScrollView 的方式，所以我希望有人可以为我澄清一下.下面的代码从一个csv中读取一堆数据，当那个代码显示出来的时候，如果有很多数据，程序基本上会尝试把所有的text/Labels压缩到GridLayout中.我希望数据可以滚动.这是代码的抽象版本:

I'm having some issues using the ScollView Widget in an attempt to make a dynamically-generated stack of labels scrollable. It's possible that I'm misunderstanding the way ScrollView should be utilized, so I'm hoping somebody could clarify it for me. The following code reads a bunch of data from a csv, and when that code is displayed, if there is a lot of data, the program will basically try to compress all the text/Labels into the GridLayout. I'd like the data to be scrollable. Here's an abstracted version of the code:

class showData(Screen):
def __init__(self, **kwargs):
    super(showData, self).__init__(**kwargs)

    self.my_data = read_csv_to_dict()
    self.data_exists = 0 if len(self.my_data) == 0 else 1 

    ### Create Widgets ###      
    layout_main = BoxLayout(orientation = 'vertical')
    layout_back_button = BoxLayout(padding = [0, 0, 0, 20])
    self.layout_data = GridLayout(cols = 3 if self.data_exists else 1)  
    self.scrollview_data = ScrollView()

    button_back = Button(text = 'Main menu')

    ### Add widgets ###
    self.add_widget(layout_main)
    layout_main.add_widget(layout_back_button)
    layout_main.add_widget(self.scrollview_data)

    layout_back_button.add_widget(button_back)

    if self.data_exists:
        self.layout_data.add_widget(Label(text = 'label 1'))
        self.layout_data.add_widget(Label(text = 'label 2'))
        self.layout_data.add_widget(Label(text = 'label 3'))
        self.display_data(self)
        self.scrollview_data.add_widget(self.layout_data)
    else:
        self.scrollview_data.add_widget(Label(text = 'Records are empty'))

    ### Create button bindings ###
    button_back.bind(on_press = switch_screen_to_main)      

def display_data(obj, self):

    data_dictReader = read_csv_to_dictReader()

    for data_row in data_dictReader:
        for value in data_row.values():
            self.layout_data.add_widget( Label( text = value))

GridLayout/data 不可滚动.有人可以告诉我如何修复上面的代码以使其可滚动吗?谢谢你.

The GridLayout/data is not scrollable. Can someone tell me how to fix the code above to make it scrollable? Thank you.

解决方案

你不见了 Kivy 文档中的一些内容 在您的 GridLayout 上.它们是确保 GridLayout 大到可以滚动"的必要条件:

You are missing a few things from the Kivy Documentation on your GridLayout. They are necessary to make sure that the GridLayout is "big enough to scroll":

  1. 您必须确保将 size_hint_y 设置为 None，因为在这种情况下默认的 1 不方便
  2. 将GridLayout的minimum_height绑定到layout.setter('height').
  3. 确保 ScrollView 具有适合滚动的大小
  1. You got to be sure that you set the size_hint_y to None, because the default 1 is not convenient in this case
  2. Bind the minimum_height of the GridLayout to layout.setter('height').
  3. Be sure that the ScrollView has the right size to accommodate the scroll

这个例子和你在文档中找到的差不多:

This example is pretty much what you find in the documentation:

from kivy.app import App
from kivy.uix.scrollview import ScrollView
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button

class Example(App):

    def build(self):
        layout = GridLayout(cols=1, spacing=10, size_hint_y=None)
        # Make sure the height is such that there is something to scroll.
        layout.bind(minimum_height=layout.setter('height'))
        for i in range(30):
            btn = Button(text=str(i), size_hint_y=None, height=40)
            layout.add_widget(btn)
        root = ScrollView()
        root.add_widget(layout)
        return root

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

在本例中，ScrollView 是 Window 的大小，但您可以使用 size_hint 和 size 属性.

In this example, the ScrollView is the size of the Window but you can manipulate it with the size_hint and size properties.

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