正在传递数据以刷新\视图\属性。Python。基维

Question

如何将data从RequestRecycleView传递到refresh_view_data？我尝试使用全局变量并在RequestRecycleView中实例化data，但仍然无法通过附加可观察的data来触发refresh_view_data。当我将RequestRecycleView作为根返回时，它就工作了，但我希望ScreenManager成为我的根。你知道吗

from kivy.config import Config
Config.set('graphics', 'multisamples', '0')
from random import sample
from string import ascii_lowercase
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import BooleanProperty
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.recycleview import RecycleView
from kivy.uix.recycleboxlayout import RecycleBoxLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior


kv = """
#:import FadeTransition kivy.uix.screenmanager.FadeTransition
ScreenManager:
    transition: FadeTransition()
    RequestsScreen:

<RequestRow@BoxLayout>

    size_hint_y: None
    orientation: 'vertical'
    row_index: id_row_index.text
    row_index:''
    pos: self.pos
    size: self.size
    Label:
        id: id_row_index 
        text: root.row_index


<RequestRecycleView@RecycleView>:               
    #id: rv
    viewclass: 'RequestRow'
    SelectableRecycleBoxLayout:
        default_size: None, dp(56)
        default_size_hint: 1, None
        size_hint_y: None
        height: self.minimum_height
        orientation: 'vertical'
        multiselect: True
        touch_multiselect: True

<RequestsScreen>
    name: 'RequestsScreen'
    BoxLayout:         
        orientation: 'vertical'
        Label: 
            text: 'recycle'
        RequestRecycleView:


"""

class SelectableRecycleBoxLayout(FocusBehavior, LayoutSelectionBehavior,
                                 RecycleBoxLayout):
    ''' Adds selection and focus behaviour to the view. '''



class RequestRow(RecycleDataViewBehavior):
    index = None
    selected = BooleanProperty(False)
    selectable = BooleanProperty(True)

    def refresh_view_attrs(self, rv, index, data):
        ''' Catch and handle the view changes '''

        self.index = index
        self.row_index = str(index)
        self.row_content = data['text']
        return super(RequestRow, self).refresh_view_attrs(
            rv, index, data)

class ScreenManagement(ScreenManager):
    pass

class RequestRecycleView(RecycleView):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.data = []
        for r in range(30):
            row = {'text': ''.join(sample(ascii_lowercase, 6))}
            self.data.append(row)

class RequestsScreen(Screen):
    pass

Builder.load_string(kv)

sm = ScreenManagement()
sm.add_widget(RequestsScreen(name = 'requests'))


class TestApp(App):
    def build(self):
        return sm

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

Answer 1

通过修改

<RequestRow@BoxLayout>

    size_hint_y: None
    orientation: 'vertical'
    row_index: id_row_index.text
    row_index:''
    pos: self.pos
    size: self.size
    Label:
        id: id_row_index 
        text: root.row_index

至

<RequestRow@BoxLayout>
    text: 'abba'
    size_hint_y: None
    orientation: 'vertical'
    row_index: id_row_index.text
    row_index:''
    pos: self.pos
    size: self.size
    Label:
        id: id_row_index 
        text: self.parent.text

产生工作代码。注意，data中的字典键应该是viewclass的属性。在RequestRow中添加的text属性提供该属性，Label中的text: self.parent.text将该文本（从viewclass）放入Label。此外，还可以替换以下行：

Builder.load_string(kv)

sm = ScreenManagement()
sm.add_widget(RequestsScreen(name = 'requests'))

只有：

sm = Builder.load_string(kv)

因为kv文件将ScreenManager指定为根对象。你知道吗