如何访问 RecycleView Kivy 的元素？

Question

I wonder to know how to access widgets in RecycleView. I constructed simple example:

main.py

from kivy.app import App
from kivy.properties import ListProperty
from kivy.uix.boxlayout import BoxLayout


class ShowBoxLayout(BoxLayout):
    keys = ListProperty()

    def __init__(self, **kwargs):
        super(ShowBoxLayout, self).__init__(**kwargs)
        self.keys = [x for x in range(5)]

    def print_list(self):
        #here I expect textinputs id but got empty dict
        print(self.ids)


class TestApp(App):
    def build(self):
        bl = ShowBoxLayout()
        return bl


app = TestApp()
app.run()

test.kv

<ShowBoxLayout>:
    RecycleView:
        viewclass: 'TextInput'
        data: [{'id': str(x)} for x in range(10)]
        RecycleGridLayout:
            cols: 1
            default_size: None, dp(26)
            default_size_hint: 1, None
            size_hint_y: None
            height: self.minimum_height
            orientation: 'vertical'
            multiselect: False
            touch_multiselect: False
    Button:
        text : 'Hello world'
        on_press : root.print_list()

In that case I cannot access TextInput inside of it with ids nor with anything else. How should I access it in order to get text in them?

This is how screen looks like.

and this is what I get after button is pressed: {} .

Answer 1

The problem is that you cannot assign to the ids dictionary in python. That can only be done in kv . So another way to access the items is to assign an id to the RecycleGridLayout , then visit each of its children. You can also define a method of your viewclass to display the entered text:

from kivy.app import App
from kivy.lang import Builder
from kivy.properties import ListProperty
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput


class ShowBoxLayout(BoxLayout):
    keys = ListProperty()

    def __init__(self, **kwargs):
        super(ShowBoxLayout, self).__init__(**kwargs)
        self.keys = [x for x in range(5)]

    def print_list(self):
        #here I expect textinputs id but got empty dict
        for child in self.ids.grid.children:
            print(child, child.text, child.id)


class MyTextInput(TextInput):
    def __init__(self, **kwargs):
        super(MyTextInput, self).__init__(**kwargs)
        self.multiline = False
        self.on_text_validate = self.get_text

    def get_text(self):
        print('get_text:', self.text)


Builder.load_string('''
<ShowBoxLayout>:
    RecycleView:
        viewclass: 'MyTextInput'
        data: [{'id': str(x)} for x in range(10)]
        RecycleGridLayout:
            id: grid
            cols: 1
            default_size: None, dp(26)
            default_size_hint: 1, None
            size_hint_y: None
            height: self.minimum_height
            orientation: 'vertical'
            multiselect: False
            touch_multiselect: False
    Button:
        text : 'Hello world'
        on_press : root.print_list()
''')


class TestApp(App):
    def build(self):
        bl = ShowBoxLayout()
        return bl


app = TestApp()
app.run()

(I used Builder.load_string() as a convenience for myself)

Note that since this is a RecycleView , the viewclass items are recycled, so the print_list() method may not visit an item for every data element, but only the ones currently displayed.