Kivy Text Input. Setting text with Clock.schedule_once() - kivy

Question

I though that it will be fairly simple to show set some text to TextInput and show it on the screen but it seems I was wrong. In the below code I need to set text Lorem ipsum... to the text input and switch the tabs. I can see the text only when I uncomment Clock.schedule_interval(self.set_text, 1). I would use Clock.schedule_once or any other way than just constantly calling set_text() method.
'''
Test of the widget TabbedPanel.
'''
from kivy.app import App
from kivy.clock import Clock
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.tabbedpanel import TabbedPanel
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.tabbedpanel import TabbedPanel, TabbedPanelHeader
from kivy.factory import Factory
theRoot = """
#:import Factory kivy.factory.Factory
<EditButton>
orientation: 'vertical'
Button:
text: 'Switch to Edit Screen'
on_press: root.change_tab()
<EditInput>
orientation: 'vertical'
TextInput:
id: text_input
<UnCloseableHeader>
color: 0,0,0,1
disabled_color: self.color
# variable tab_width
text: 'tabx'
size_hint_x: None
width: self.texture_size[0] + 40
BoxLayout:
pos: root.pos
size_hint: None, None
size_y: 20
padding: 3
Label:
id: lbl
text: root.text
<MainTabbedPanel>:
size_hint: (1, 1)
do_default_tab: False
#default_tab: edit_button_tab
tab_width: 130
FloatLayout:
EditButton:
id: edit_button
EditInput:
id: edit_input
UnCloseableHeader:
id: edit_button_tab
text: 'Edit'
content: edit_button.__self__
UnCloseableHeader:
id: edit_input_tab
text: 'Edit Tab'
content: edit_input.__self__
MainTabbedPanel:
"""
class EditInput(BoxLayout):
notes = ''
def __init__(self, **kwargs):
super(EditInput, self).__init__(**kwargs)
print('NOTES', self.notes)
#Clock.schedule_interval(self.set_text, 1)
Clock.schedule_once(self.set_text, -1)
def set_text(self, dt):
print('SET TEXT', self.notes)
self.ids.text_input.text = self.notes
class EditButton(BoxLayout):
def __init__(self, **kwargs):
super(EditButton, self).__init__(**kwargs)
def change_tab(self):
EditInput.notes = 'Lorem ipsum...'
EditInput()
mtp = App.get_running_app().root
mtp.switch_to(mtp.ids.edit_input_tab)
class MainTabbedPanel(TabbedPanel):
tab = ''
def __init__(self, **kwargs):
super(MainTabbedPanel, self).__init__(**kwargs)
self.tabs_showing = True
class UnCloseableHeader(TabbedPanelHeader):
pass
Factory.register('UnCloseableHeader', cls=UnCloseableHeader)
sm = Builder.load_string(theRoot)
class TabbedPanelApp(App):
def build(self):
return sm
if __name__ == '__main__':
TabbedPanelApp().run()
EDIT
I've tried with:
SNIPPET
def change_tab(self):
EditInput.notes = 'Lorem ipsum...'
EditInput()
and:
Clock.schedule_once(self.set_text, 1)
It works in about 50% of cases witch is pretty hard to understand

Answer 1

You can take advantage of Property binding that kv sets up for you. Change your EditInput class to simply:
class EditInput(BoxLayout):
notes = StringProperty('')
no need for any of the methods. Then, in your kv, change the EditInput rule to:
<EditInput>
orientation: 'vertical'
TextInput:
id: text_input
text: root.notes
and change the change_tab method of EditButton to:
def change_tab(self):
mtp = App.get_running_app().root
mtp.ids.edit_input.notes = 'Lorem ipsum...'
mtp.switch_to(mtp.ids.edit_input_tab)
Note that changing the notes property of the EditInput instance will automatically change the TextInput (due to the property binding set up by kv).
Also, the line in change_tab():
EditInput()
is creating a new instance of the EditInput class that is unused and will be garbage collected.