如何在kivy modalview中动态更新标记文本

Question

I am trying to update a label field dynamically from the contents of a TextInput in a ModalView. The idea is that in the TextInput one enters plain text including markup formatting and you will see the results directly in the Label field with markup = True.

Unfortunately I do not know how to access the Label item in the ModalView. Who can help? See the example code below.

Thanks in advance.

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.modalview import ModalView
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.textinput import TextInput
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.properties import ObjectProperty, StringProperty

kv = """
<Test>:
    canvas:
        Color:
            rgba: 0.4, 0.5, 0.6, 1
        Rectangle:
            size: self.size
            pos: self.pos
    Button:
        size_hint: None, None
        size: 3 * dp(48), dp(48)
        text: 'Edit'
        on_press: root.showedit()
"""

Builder.load_string(kv)


class Test(BoxLayout):
    minput_text = StringProperty('Welcome')
    txtresult = ObjectProperty()

    def showedit(self):
        mview = ModalView(id='mviewid', size_hint=(0.4, 0.6), auto_dismiss=False, background='./images/noimage.png')
        mblt = BoxLayout(orientation='vertical', padding=(24))
        minp = TextInput(id='inptxt', text='', hint_text='Start typing text with markup here', size_hint=(1,0.5),multiline=True)
        minp.bind(text=self.on_inptext)

        mtxt = Label(id='txtresult',text='displays formatted text', color=(0.3,0.3,0.3), size_hint=(1,0.5),markup=True)
        mcnf = Button(text='OK', size=(144,48), size_hint=(None,None))
        mcnf.bind(on_press=mview.dismiss)

        mblt.add_widget(minp)
        mblt.add_widget(mtxt)
        mblt.add_widget(mcnf)
        mview.add_widget(mblt)
        mview.bind(on_dismiss=self.print_text)
        mview.open()

    def on_inptext(self, instance, value):
        self.minput_text = value

    def print_text(self, *args):
        print self.minput_text


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


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

Answer 1

You have to make a binding between the TextIntput text and the Label , for this we can use a lambda function and setattr .

class Test(BoxLayout):
    minput_text = StringProperty('Welcome')
    txtresult = ObjectProperty()

    def showedit(self):
        mview = ModalView(id='mviewid', size_hint=(0.4, 0.6), auto_dismiss=False, background='./images/noimage.png')
        mblt = BoxLayout(orientation='vertical', padding=(24))
        minp = TextInput(id='inptxt', text='', hint_text='Start typing text with markup here', size_hint=(1,0.5),multiline=True)
        minp.bind(text=self.on_inptext)

        mtxt = Label(id='txtresult',text='displays formatted text', color=(0.3,0.3,0.3), size_hint=(1,0.5),markup=True)
        mcnf = Button(text='OK', size=(144,48), size_hint=(None,None))
        mcnf.bind(on_press=mview.dismiss)

        mblt.add_widget(minp)
        mblt.add_widget(mtxt)
        mblt.add_widget(mcnf)
        mview.add_widget(mblt)
        mview.bind(on_dismiss=self.print_text)
        # binding between TextInput text and Label text
        minp.bind(text=lambda instance, value: setattr(mtxt, 'text',value))

        mview.open()

    def on_inptext(self, instance, value):
        self.minput_text = value

    def print_text(self, *args):
        print(self.minput_text)