在 Python 中手动更新 Kivy RecycleView

Question

从 RecycleView 类外部更改数据时，RecycleView 不会更新其表。作为总结，我正在尝试创建一个简单的股票投资组合管理器。

我有一个自定义的 RecycleView 类，我称之为 RecycleViewPortfolio，它继承自 RecycleView。在我的 .kv 文件中，我有三个按钮连接到我的 RecycleViewPortfolio 类中的函数 populate_1、populate_2 和 populate_3。每当我按下按钮并调用任何填充函数时，RecycleView 都会按预期运行。

但是，每当我从 RecycleViewPortfolio 类之外更改 RecycleView 数据时，该表都不会更新。例如，我设置了一个全局变量，该变量已导入到我的 .py 文件和 .kv 文件中。每当此全局变量中的数据发生更改时，我希望能够更新表。

我尝试查看 Kivy 的文档，其中提到了可以解决此问题的不同功能。但我想我对如何应用这些方法一无所知。

import StackOverflow.globalvariables as GlobalVariables
from kivy.app import App
from kivy.uix.popup import Popup
from kivy.uix.button import Button
from kivy.uix.gridlayout import GridLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview import RecycleView
from kivy.uix.recyclegridlayout import RecycleGridLayout
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior
from kivy.properties import BooleanProperty, ListProperty, ObjectProperty


class AddPopup(Popup):
    """Popup for adding asset"""
    asset_name = ObjectProperty
    asset_price = ObjectProperty
    asset_amount = ObjectProperty
    currency = ObjectProperty
    asset_class = ObjectProperty
    wrapped_button = ObjectProperty()

    def __init__(self, *args, **kwargs):
        super(AddPopup, self).__init__(*args, **kwargs)

    def open(self, correct=True):
        super(AddPopup, self).open(correct)

    def save_asset(self):
        # Make sure no input is empty
        if self.asset_name.text.strip() and self.asset_price.text.strip()\
                and self.asset_amount.text.strip() and self.currency.text.strip()\
                and self.asset_class.text.strip():

            GlobalVariables.rv_data_global = [{'text': self.asset_name.text.strip()},
                                              {'text': self.asset_amount.text.strip()},
                                              {'text': self.asset_price.text.strip()}]
            self.dismiss()

class RecycleViewPortfolio(RecycleView):

    def __init__(self, **kwargs):
        super(RecycleViewPortfolio, self).__init__(**kwargs)
        self.populate_2()

    def populate_1(self):
        root = App.get_running_app().root
        root.add_popup.open(True)
        self.data = GlobalVariables.rv_data_global

    def populate_2(self):
        self.data = [{'text': str(x)} for x in range(0, 6)]

    def populate_3(self):
        self.data = [{'text': str(x)} for x in range(6, 12)]

class PortfolioRoot(GridLayout):
    """root to all screens"""
    add_popup = ObjectProperty(None)
    list = ListProperty([])

    def __init__(self, **kwargs):
        super(PortfolioRoot, self).__init__(**kwargs)
        self.add_popup = AddPopup()

    def test_set_data(self):
        GlobalVariables.rv_data_global = [{'text': str(x)} for x in range(12, 18)]



class SelectableRecycleGridLayout(FocusBehavior, LayoutSelectionBehavior, # View Behavior
                                  RecycleGridLayout):
    ''' Adds selection and focus behaviour to the view. '''


class SelectableButton(RecycleDataViewBehavior, Button): # Data Behavior
    ''' Add selection support to the Label '''
    index = None
    selected = BooleanProperty(True)
    selectable = BooleanProperty(True)

    def refresh_view_attrs(self, rv, index, data):
        ''' Catch and handle the view changes '''
        self.index = index
        return super(SelectableButton, self).refresh_view_attrs(
            rv, index, data)

    def on_touch_down(self, touch):
        ''' Add selection on touch down '''
        if super(SelectableButton, self).on_touch_down(touch):
            return True
        if self.collide_point(*touch.pos) and self.selectable:
            return self.parent.select_with_touch(self.index, touch)

    def apply_selection(self, rv, index, is_selected):
        ''' Respond to the selection of items in the view. '''
        self.selected = is_selected


class PortfolioApp(App):
    """App object"""

    def __init__(self, **kwargs):
        super(PortfolioApp, self).__init__(**kwargs)

    def build(self):
        return PortfolioRoot()

PortfolioApp().run()

.kv 文件

    #:kivy 1.10.0
#:import GlobalVariables StackOverflow.globalvariables

<SelectableButton>:
    # Draw a background to indicate selection
    canvas.before:
        Color:
            rgba: (0, 0.517, 0.705, 1) if self.selected else (0, 0.517, 0.705, 1)
        Rectangle:
            pos: self.pos
            size: self.size
    background_color: [1, 0, 0, 1]  if self.selected else [1, 1, 1, 1]  # dark red else dark grey
    on_release:
        print("Pressed")

<WrappedLabel@Label>:
    size_hint_y: None
    height: self.texture_size[1] + (self.texture_size[1]/2)
    markup: True

<RecycleViewPortfolio@RecycleView>:
    viewclass: 'SelectableButton'
    target_id: None
#    id: rv_data_list
    data: GlobalVariables.rv_data_global
    SelectableRecycleGridLayout:
        cols: 3
        key_selection: 'selectable'
        default_size: None, dp(26)
        default_size_hint: 1, None
        size_hint_y: None
        height: self.minimum_height
        multiselect: True
        touch_multiselect: True

<PortfolioRoot>:
    BoxLayout:
        list: rv_data_list
        size: root.size
        orientation: 'vertical'
        WrappedLabel:
            text: "[b] Portfolio Manager [/b]"
            font_size: min(root.height, root.width) / 10
        GridLayout:
            size_hint_y: None
            height: root.height * 0.1
            cols: 4
            rows: 1
            #  Settings
            padding: root.width * 0.001, root.height * 0.001
            spacing: min(root.width, root.height) * 0.001

            Button:
                text: "Add"
                background_color: [1, 1, 1, 1]
                on_release:
                    rv_data_list.populate_1()
                    print("Add")

            Button:
                text: "Change"
                background_color: [1, 1, 1, 1]
                on_release:
                    rv_data_list.populate_2()
                    print("Change")

            Button:
                text: "Remove"
                background_color: [1, 1, 1, 1]
                on_release:
                    rv_data_list.populate_3()
                    print("Remove")

            Button:
                text: "Test"
                background_color: [1, 1, 1, 1]
                on_release:
                    root.test_set_data()
                    print("Test set data")

        RecycleViewPortfolio:
            id: rv_data_list

<AddPopup>:
    size_hint: 0.8, 0.8
    title: "Add Asset"
    title_size: root.height * 0.05
    auto_dismiss: False
    asset_name: asset_name
    asset_price: asset_price
    asset_amount: asset_amount
    currency: currency
    asset_class:asset_class
    wrapped_button: wrapped_button
    BoxLayout:
        orientation: 'vertical'
        GridLayout:
            rows: 5
            cols: 2
            padding: root.width * 0.02, root.height * 0.02
            spacing: min(root.width, root.height) * 0.02

            Label:
                id: asset_name_label
                text: "Asset name"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_name
                text: "Asset name"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: asset_price_label
                text: "Asset price"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_price
                text: "asset"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: asset_amount_label
                text: "Asset amount"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_amount
                text: "Asset amount"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: currency_label
                text: "Asset currency"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: currency
                text: "currency"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            Label:
                id: asset_class_label
                text: "Asset class"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
            TextInput:
                id: asset_class
                text: "Asset class"
                halign: "center"
                font_size: root.height/25
                text_size: self.width, None
                center_y: .5
        Button:
            id: wrapped_button
            text: "Save"
            size_hint: 1, None
            height: root.height / 8
            on_release: root.save_asset()
        Button:
            id: wrapped_button
            text: "close"
            size_hint: 1, None
            height: root.height / 8
            on_release: root.dismiss()

全局变量.py

# global variables
rv_data_global = []

我希望能够创建一个弹出窗口，在其中添加存储在全局变量中的信息，并在进行更改后调用 RecycleView 进行更新。

编辑：添加了一个工作示例

这个例子展示了我如何使用“更改”和“删除”按钮来按预期填充 RecycleView。但是，当按下添加按钮并出现弹出窗口并按下保存按钮时，RecycleView 不会更新。如果再次按下添加按钮并直接关闭，则 RecyleView 会更新并显示正确的信息。

“测试”按钮也是如此，我在其中调用了一个更改全局变量的函数。从那里我不知道如何更新视图，因为我不再在 RecycleView 类下工作。

TLDR； 数据更改后手动更新 RecycleView 的方法。

Answer 1

我找到了我的一个问题的答案。通过添加：

self.ids.rv_data_list.data = GlobalVariables.rv_data_global
self.ids.rv_data_list.refresh_from_data()

对于 test_set_data 函数，我现在可以按照我的要求刷新数据。因此，神奇的是 refresh_from_data() 方法。

通过 App.get_running_app() 我能够从弹出类访问 refresh_from_data() 命令。

root = App.get_running_app().root
root.ids.rv_data_list.data = GlobalVariables.rv_data_global
root.ids.rv_data_list.refresh_from_data()

我似乎在这里解决了我自己的问题。但如果有人有更好或更清洁的解决方案，请告诉我。