I would like my label to have exactly the height it needs to display its text. It is inside a RecycleView. I think my code should work outside an RecycleView.
How can I make the Label big enough so that its content can easily be read? In the same way as it already works for CodeInput and TextInput.
from kivy.base import runTouchApp
from kivy.lang import Builder
from kivy.uix.recycleview import RecycleView
from kivy.uix.label import Label
from kivy.uix.recycleboxlayout import RecycleBoxLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.properties import StringProperty
Builder.load_string('''
<RV>:
viewclass: 'SnippetView'
RecycleBoxLayout:
default_size: None, dp(56)
default_size_hint: 1, None
size_hint_y: None
height: self.minimum_height
orientation: 'vertical'
spacing: 10
<SnippetView>:
canvas.before:
Color:
rgb: (255,0,0)
Rectangle:
pos: self.pos
size: self.size
orientation: 'vertical'
Label:
text: root.heading
text_size: root.width, None
size: self.texture_size
TextInput:
text: root.dscrpt
size_hint_y: None
height: self.minimum_height
CodeInput:
text: root.code
size_hint_y: None
height: self.minimum_height
''')
class SnippetView(BoxLayout):
heading = StringProperty()
dscrpt = StringProperty()
code = StringProperty()
class RV(RecycleView):
def __init__(self, **kwargs):
super(RV, self).__init__(**kwargs)
self.data = [{'heading': str(x),'dscrpt': str(x),'code': str(x)} for x in range(100)]
rv = RV()
runTouchApp(rv)
I am also thankful for any comments regarding RecycleView in general since I am using it for the first time.
You must bind a method to update the height of your SnippetView when the value of the label change because you have fixed it in the rule of your RV. Try this:
...
Builder.load_string('''
...
<SnippetView>:
canvas.before:
Color:
rgb: (255,0,0)
Rectangle:
pos: self.pos
size: self.size
orientation: 'vertical'
Label:
id: l
text: root.heading
text_size: root.width, None
size: self.texture_size
TextInput:
id: ti
text: root.dscrpt
size_hint_y: None
height: self.minimum_height
CodeInput:
id: ci
text: root.code
size_hint_y: None
height: self.minimum_height
''')
class SnippetView(BoxLayout):
heading = StringProperty()
dscrpt = StringProperty()
code = StringProperty()
def __init__(self, **kwargs):
super(SnippetView, self).__init__(**kwargs)
self.ids.l.bind(height=self.update)
def update(self, *args):
self.height = self.ids.l.texture_size[1] + self.ids.ti.height + self.ids.ci.height
...
Related
I´m learning kivy, and it has passed 3 weeks since i face this problem without encounter a solution, so i hope any of u guys could help me, i would appreciate it.
I have a main file:
from app import MyProgramApp
if __name__ == "__main__":
winapp = MyProgramApp()
winapp.run()
from where i start my app. Then i have a directory called "app", inside there is the following "init.py" file.
from kivy.app import App
from kivy.utils import QueryDict, rgba
from kivy.core.window import Window
from .view import MainWindow
Window.minimum_width = 500
Window.minimum_height = 650
Window.maximize()
class MyProgramApp(App):
colors = QueryDict()
colors.primary = rgba('#2D9CDB')
colors.secondary = rgba('#16213E')
colors.succes = rgba('#1FC98E')
colors.warning = rgba('#F2C94C')
colors.danger = rgba('#E85757')
colors.grey_dark = rgba('#C4C4C4')
colors.grey_light = rgba('#F5F5F5')
colors.black = rgba('#A1A1A1')
colors.white = rgba('#FFFFFF')
def build(self):
return MainWindow()
Same folder app, i have the following "view.py".
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.behaviors import ToggleButtonBehavior
from kivy.properties import StringProperty
from kivy.uix.screenmanager import ScreenManager
class MainWindow(BoxLayout):
username = StringProperty("Usuario")
def __init__(self, **kw):
super().__init__(**kw)
def on_press_home(self):
self.ids.scrn_mngr.current = "scrn_home"
class ViewManager(ScreenManager):
def __init__(self, **kw):
super().__init__(**kw)
class NavTab(ToggleButtonBehavior, BoxLayout):
text = StringProperty('')
icon = StringProperty('')
def __init__(self, **kw):
super().__init__(**kw)
and finally for that folder i have "myprogram.kv"
#:kivy 2.1.0
#:import Home views.home.Home
<MainWindow>:
spacing: dp(8)
canvas.before:
Color:
rgba: app.colors.white
Rectangle:
pos: self.pos
size: self.size
# NAVIGATION BAR
BoxLayout:
id: nav_menu
size_hint_x: .2
orientation: "vertical"
size_hint_min_x: dp(100)
# LOGO
BoxLayout:
id: logo_nbox
size_hint_y: .1
size_hint_min_y: dp(70)
padding: dp(16)
AnchorLayout:
anchor_x: "right"
size_hint_x: None
width: dp(52)
halign: "left"
Label:
text: "COMPANY"
halign: "center"
BoxLayout:
orientation: "vertical"
Label:
text: "COMPANY"
halign: "center"
Label:
text: "Phrase"
halign: "center"
# OPTIONS
GridLayout:
id: tabs_box
cols: 1
spacing: dp(4)
size_hint_y: .5
canvas.before:
Color:
rgba: app.colors.grey_dark
Rectangle:
pos: self.pos
size: [self.size[0], dp(1)]
NavTab:
text: "Home"
state: "down"
on_press: root.on_press_home()
# BODY
BoxLayout:
size_hint_x: .8
spacing: dp(8)
orientation: "vertical"
padding: [dp(16), dp(8), dp(12), dp(8)]
canvas.before:
Color:
rgba: app.colors.grey_light
Rectangle:
pos: self.pos
size: self.size
# SCREENS
BoxLayout:
ViewManager:
id: scrn_mngr
<ViewManager>:
Screen:
name: "scrn_home"
Home:
id: home
<NavTab>:
background_normal: ""
background_down: ""
background_color: [0,0,0,0]
group: "tabs"
size_hint_y: None
height: dp(45)
spacing: dp(4)
canvas.before:
Color:
rgba: [0,0,0,0] if self.state == "normal" else rgba("#E1F1FF")
Rectangle:
pos: self.pos
size: self.size
Color:
rgba: [0,0,0,0] if self.state == "normal" else app.colors.primary
Rectangle:
pos: [self.pos[0]+self.size[0]-dp(1), self.pos[1]]
size: [dp(8), self.size[1]]
Label:
halign: "left"
valign: "middle"
text: root.text
color: app.colors.grey_dark if root.state == "normal" else app.colors.primary
Then i got another folder called "views" inside i have another folder called "home", inside home we encounter 3 files "init.py", "home.kv", "home.py". the first one "init.py" is the following.
from .home import Home
then we got "home.kv".
#:kivy 2.1.0
<Home>:
orientation: "vertical"
Label:
size_hint_y: .1
text: "Other"
Button:
size_hint_y: .1
text: "popup"
on_press: root.open_popup()
BoxLayout:
size_hint_y: .8
id: home_box
<SomePopup>:
title: "SOME TITLE"
title_align: "center"
title_color: app.colors.primary
size_hint: .25, .8
size_hint_min_x: dp(200)
pos_hint: {"x": .1, "top": .9}
BoxLayout:
orientation: "vertical"
padding: [dp(0), dp(12), dp(0), dp(12)]
Label:
text: "Some text"
Button:
text: "create buttons on box"
on_press: root.modify_home_box()
and finally and the problem that i´m facing is whit the following file "home.py"
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.factory import Factory
from kivy.uix.popup import Popup
from kivy.uix.button import Button
from kivy.app import App
Builder.load_file('views/home/home.kv')
class Home(BoxLayout):
def __init__(self, **kwargs):
super().__init__(**kwargs)
def open_popup(self):
Factory.SomePopup().open()
class SomePopup(Popup):
def __init__(self, **kw):
super().__init__(**kw)
def modify_home_box(self):
my_app = App.get_running_app().root
my_box = my_app.ids.home.ids.home_box
custom_button = Button(
text = "something"
)
my_box.add_widget(custom_button)
That i´m trying to do is actually modify "home_box" with is store on ids Home dictionary, i also try with ObjectProperty (but that gives and Attribute Error, since i only could read propertys but doesnt modify it), instance of a new Home class doesnt work... searching for current app in App appear doesnt work since Home is store i think on screenManager...
I need add a button or some widget to "home_box" from outside class "SomePopup". I also drop here a repository on github with the whole code. github_repo
I don't know how to solve my issue, and i try with the resources available here on stack as well other net places... any help would be appreciate.
Just a very complicated path to the widget of interest. In your modify_home_box() method, try replacing:
my_app = App.get_running_app().root
my_box = my_app.ids.home.ids.home_box
with:
my_app = App.get_running_app().root
my_box = my_app.ids.scrn_mngr.ids.home.ids.home_box
I have the following code where I would like to be able to click on the navigation drawer, select Status under Users, input the name and then be sent to a given screen with the current_user now populated.
main.py
from kivy.uix.behaviors import CoverBehavior
from kivy import utils
from kivy.properties import ObjectProperty, ListProperty, NumericProperty, StringProperty, BooleanProperty
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.screenmanager import ScreenManager
from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.core.window import Window
from kivy.uix.boxlayout import BoxLayout
from kivymd.theming import ThemableBehavior
from kivymd.uix.button import MDFlatButton
from kivymd.uix.dialog import MDDialog
from kivymd.uix.list import MDList
#from models import ServerInfo
from navigation_drawer import navigation_helper
Window.fullscreen = 'auto'
class ItemWidget(BoxLayout):
sid = NumericProperty()
name = StringProperty()
work = NumericProperty()
is_disabled = BooleanProperty()
description = StringProperty()
has_issue = BooleanProperty()
class MainWidget(FloatLayout):
recycleView = ObjectProperty()
items = ListProperty()
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.items = [
#ServerInfo(1, "server1", 95, "desc", is_disabled=False, has_issue=False),
]
# Put the servers with issues on top, otherwise sort by name
self.items = sorted((s for s in self.items), key=lambda x: (not(x.has_issue),x.name))
# Load the server information when the recycleView is called
def on_recycleView(self, widget, parent):
self.recycleView.data = [
m.get_dictionary() for m in self.items
]
class Content(BoxLayout):
pass
class DemoApp(MDApp):
class ContentNavigationDrawer(BoxLayout):
pass
class DrawerList(ThemableBehavior, MDList):
pass
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.dialog = None
# set main interface
self.manager = ScreenManager()
self.current_user = ""
# return main interface
#return self.manager
def build(self):
screen = Builder.load_string(navigation_helper)
return screen
def on_start(self):
pass
def dialog_close(self, *args):
self.dialog.dismiss(force=True)
def set_current_user(self,user,sm):
self.current_user = user
# Send over to given screen
# ???? = sm
def show_user_input_dialog(self,user,screen):
#print(sm.current)
if not self.dialog:
self.dialog = MDDialog(
title="Input Username:",
type="custom",
content_cls=Content(),
buttons=[
MDFlatButton(
text="CANCEL",
theme_text_color="Custom",
text_color=self.theme_cls.primary_color,
on_release=self.dialog_close
),
MDFlatButton(
text="OK",
theme_text_color="Custom",
text_color=self.theme_cls.primary_color,
#on_release=self.set_current_user(user,screen)
on_release=self.dialog_close
),
],
)
# Send to user management page with current user now populated
# Fails as sm is a str instead of ScreenManager()
#sm.current = 'user_management'
self.dialog.open()
DemoApp().run()
navigation_drawer.py
navigation_helper = """
Screen:
MDNavigationLayout:
ScreenManager:
id: screenManager
Screen:
name: "monitor"
BoxLayout:
orientation: 'vertical'
MDToolbar:
title: 'Administration'
left_action_items: [["menu", lambda x: nav_drawer.set_state('toggle')]]
elevation:5
MainWidget:
Screen:
name: "user_management"
BoxLayout:
orientation: 'vertical'
MDToolbar:
title: 'Administration'
left_action_items: [["menu", lambda x: nav_drawer.set_state('toggle')]]
elevation:5
UserManagement:
MDNavigationDrawer:
id: nav_drawer
ContentNavigationDrawer:
orientation: 'vertical'
padding: "2dp"
spacing: "2dp"
ScrollView:
DrawerList:
id: md_list
MDList:
TwoLineIconListItem:
text: "Monitor"
secondary_text: "Monitor servers"
on_release: screenManager.current = 'monitor'
IconLeftWidget:
icon: "monitor"
MDLabel:
padding: dp(10), dp(0)
text: "Users"
bold: True
font_size: dp(22)
size_hint_y: None
OneLineIconListItem:
text: "Status"
on_release: app.show_user_input_dialog('abc999','user_management')
<Content>
orientation: "vertical"
spacing: "12dp"
size_hint_y: None
height: "60dp"
MDTextField:
id: username_input
hint_text: "Username"
<UserManagement#BoxLayout>:
Label:
text: "Users"
<MainWidget>:
id: mainWidgetId2
recycleView: recycleView
CoverImage:
source: 'images/monitor.png'
# Darken the photo
canvas:
Color:
rgba: 0, 0, 0, .6
Rectangle:
pos: self.pos
size: self.size
BoxLayout:
padding: dp(20)
spacing: dp(10)
BoxLayout:
orientation: "horizontal"
BoxLayout:
canvas.before:
Color:
rgba: 1,1,1,.1
# Use a float layout to round the corners
RoundedRectangle:
pos: self.pos
size: self.size
RecycleView:
id: recycleView
viewclass: 'ItemWidget'
RecycleGridLayout:
cols: 1
default_size: self.parent.width / 5, dp(60)
default_size_hint: 1, None
size_hint_y: None
height: self.minimum_height
width: self.minimum_width
spacing: dp(155), dp(0)
BoxLayout:
orientation: "vertical"
spacing: dp(10)
BoxLayout:
spacing: dp(10)
BoxLayout:
canvas.before:
Color:
rgba: 1,1,1,.1
# Use a float layout to round the corners
RoundedRectangle:
pos: self.pos
size: self.size
Label:
text: "APPS"
BoxLayout:
canvas.before:
Color:
rgba: 1,1,1,.1
# Use a float layout to round the corners
RoundedRectangle:
pos: self.pos
size: self.size
Label:
text: "OTHER"
BoxLayout:
canvas.before:
Color:
rgba: 1,1,1,.1
# Use a float layout to round the corners
RoundedRectangle:
pos: self.pos
size: self.size
Label:
text: "MOUNTS"
BoxLayout:
canvas.before:
Color:
rgba: 1,1,1,.1
# Use a float layout to round the corners
RoundedRectangle:
pos: self.pos
size: self.size
Label:
text: "RECENT ACTIVITY"
<CoverImage#CoverBehavior+Image>:
reference_size: self.texture_size
<ItemWidget>:
BoxLayout:
#size_hint_max_x: dp(360)
size_hint_min_x: dp(150)
orientation: "horizontal"
BoxLayout:
orientation: "horizontal"
Button:
# Use the on_press to print troubleshooting info, otherwise comment out
on_press: print(self.background_color)
padding: dp(10), dp(10)
text_size: self.size
font_size: dp(22) if root.has_issue else dp(18)
background_color: .5,1,1,.6 #utils.get_random_color(alpha=.6)
halign: "left"
valign: "top"
size: 1,1
# Show last 4 of server name
text: str(root.name).upper()[-4:]
bold: True
color: (1,0,0) if root.has_issue else (1,1,1)
Button:
background_color: .5,1,1,.6
text_size: self.size
valign: "center"
halign: "center"
text: str(root.work)
padding: dp(8), dp(8)
bold: True if root.work > 90 else False
color: (1,0,0) if root.work > 90 else (1,1,1) # Red if greater than 90
"""
Questions:
How do I get the value from this so that I can pass the value instead of the hardcoded username of abc999
MDTextField:
id: username_input
How do I send to the given screen (user_management here) from
def set_current_user(self,user,sm):
self.current_user = user
# Send over to given screen
# ???? = sm
You can toggle commenting on the two on_release below to see the issue
MDFlatButton(
text="OK",
theme_text_color="Custom",
text_color=self.theme_cls.primary_color,
#on_release=self.set_current_user(user,screen)
on_release=self.dialog_close
You can do what you want by modifying set_current_user() to:
def set_current_user(self, button):
self.current_user = self.dialog.content_cls.ids.username_input.text
self.dialog_close()
self.root.ids.users.add_widget(Label(text=self.current_user))
sm = self.root.ids.screenManager
sm.current = 'user_management'
The above code requires the addition of an id to the UserManagerment in the kv:
UserManagement:
id: users
This just adds a new Label with the name of the user.
I'm creating a simple Database-GUI and want to add two lines to a form. each line is a DataField-Object, and contains a label and a TextInput organised by a horizontal Boxlayout. up to here all fine.
The Form-Widget contains also a BoxLayout (Orientaton: "Vertical") organizing the two DataField-Objects by listing them up under each other, but it doesn't work...
My Question: WHY??? and how can I fix it?
dbgui3.py
from kivy import require
require("2.0.0")
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.properties import StringProperty, ObjectProperty
class DataField(Widget):
title = StringProperty()
pass
class Form(Widget):
b = ObjectProperty()
def __init__(self, *rec, **kwargs):
super().__init__()
for df in rec:
self.b.add_widget(DataField(title=df))
class DbGui3(App):
def build(self):
return Form("hello", "world")
if __name__ == '__main__':
DbGui3().run()
dbgui3.kv
<DataField>:
text: txt.text
BoxLayout:
orientation: "horizontal"
size_hint: None, None
size: root.width, 30
canvas:
Color:
rgb: 0.2,0.2,0.2
Rectangle:
size: self.size
Label:
text: root.title
size_hint: None, 1
width: self.texture_size[0]
TextInput:
id:txt
multiline: False
on_text_validate: print("text validated:" + root.text)
<Form>:
b:b
BoxLayout:
id: b
orientation: "vertical"
size_hint: None, None
size: root.width, root.height
canvas:
Color:
rgb: 0.1,0.2,0.3
Rectangle:
size: self.size
The problem is that you are using Widget as a base class for your DataField and Form classes. The Widget class does not take any notice of things like size_hint, pos_hint, and others. It is not intended to be a Layout. I suggest you use BoxLayout as the base for your DataField and some other Layout (perhaps FloatLayout) as the base class for Form. Using this suggestion, your class definitions could be:
class DataField(BoxLayout):
title = StringProperty("example")
class Form(FloatLayout):
pass
Then modifying your kv:
<DataField>:
size_hint: 1, None
height: 30
orientation: "horizontal"
Label:
size_hint: None, None
size: self.texture_size[0]*1.3, root.height
text: root.title
TextInput:
multiline: False
on_text_validate: print(root.title)
<Form>:
BoxLayout:
orientation: "vertical"
size_hint: None, None
size: root.width/2, root.height/2
DataField:
title: "hello"
DataField:
title: "world"
I think this will do what you want.
Any assistance is much appreciated.
Here's an example code to show the problem,
when the ('Press me') button is pressed and the widget resized(white box come within view), the TabbedPanel redraws like a glitch (even though its not).
I've tried changing the layout order and toyed a bit with the animation, no
I wish to prevent that blinking behaviour of the tabbedpanel on the left.
import kivy
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.animation import Animation
from kivy.lang import Builder
Builder.load_string('''
<Main>:
BoxLayout:
orientation:'vertical'
BoxLayout:
id: main_screen
orientation: 'horizontal'
TabbedPanel:
do_default_tab: False
tab_pos: 'left_top'
tab_width: main_screen.height/4
TabbedPanelItem:
text: 'four'
TabbedPanelItem:
text: 'three'
TabbedPanelItem:
text: 'two'
TabbedPanelItem:
text: 'one'
BoxLayout:
id: swidget
slide: 0
size_hint: None, None
height: main_screen.height
width: self.slide
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
Button:
size_hint_y: None
height: '33dp'
text: 'Press me'
on_release: root.display_widget(swidget)
''')
class Main(BoxLayout):
def __init__(self, **kwargs):
super(Main, self).__init__(**kwargs)
def display_widget(self, widget):
swidget = widget
if swidget.slide == 0:
anim = Animation(slide=105, duration=0.6)
anim.start(widget)
else:
anim = Animation(slide=0, duration=0.6)
anim.start(widget)
class TabbedApp(App):
def build(self):
return Main()
TabbedApp().run()
Add AnchorLayout to be the parent of swidget / BoxLayout and when the animation starts, it won't impact the instantiated TabbedPanel.
Snippets
AnchorLayout:
anchor_x: 'right'
anchor_y: 'top'
size_hint_x: None
width: 0
BoxLayout:
id: swidget
slide: 0
size_hint_x: None
width: self.slide
canvas:
Color:
rgba: 1,1,1,1
Rectangle:
pos: self.pos
size: self.size
I'm new to kivy , I'm trying to write an application using kivy in python, I got struck at one point where i have to read text from textinput whenever it is changed and based on that i want to implement my button's functionality - I have gone through all the documentation but i couldn't figure out how to do it - Can any body tell me how can I resolve this or am I missing something?
from __future__ import print_function
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.core.image import Image
from kivy.uix.floatlayout import FloatLayout
from kivy.graphics import *
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput
from kivy.uix.popup import Popup
from kivy.properties import ObjectProperty
import walascan
from kivy.clock import Clock
import os
kv = """
<KartScan>:
IntroScreen:
<IntroScreen#Screen>:
orientation: 'horizontal'
name: 'introscreen'
canvas.before:
Rectangle:
pos: self.pos
size: self.size
source: 'index.png'
AnchorLayout:
anchor_x: 'center'
anchor_y: 'center'
BoxLayout:
orientation:'horizontal'
size_hint: .5, .1
canvas:
Color:
rgb: 1, 1, 1
Rectangle:
pos: self.pos
size: self.size
spacing: 20
pos_hint: {'center_x':.8, 'center_y': .8}
AnchorLayout:
anchor_x: 'left'
size_hint_x: .5
TextInput:
id: waybill
width: 20
text: "Enter Waybill No."
multiline: False
height: self.minimum_height
size_hint_y: None
font_size: 30
focus: True
on_text_validate: app.on_waybill()
AnchorLayout:
anchor_x: 'right'
size_hint_x: None
Button:
size_hint: None, None
height: 50
width: self.texture_size[0]
padding: 10, 10
text: "Add"
on_press:app.buttonClicked()
on_release: root.current = 'mainpage'
AnchorLayout:
anchor_x: 'right'
size_hint_x: None
Button:
size_hint: None, None
height: 50
width: self.texture_size[0]
padding: 10, 10
text: "Compare"
on_press:app.buttonClicked()
on_release: root.current = 'mainpage'
"""
Builder.load_string(kv)
waybill = TextInput(text="Enter Waybill No.", multiline=False)
class KartScan(FloatLayout):
def __init__(self, **kwargs):
super(KartScan, self).__init__(**kwargs)
self.register_event_type('on_text_validate')
def on_text(self, *args):
print('new value is ', waybill.text)
def on_text_validate(self):
pass
def on_focus(self, obj, focused):
if not focused:
self.dispatch('on_text_validate')
class KartScanApp(App):
def build(self):
return KartScan()
def buttonClicked(self):
popup = Popup(title='Result',
content=Label(text=self.on_waybill()),
size_hint=(None, None), size=(100, 100))
popup.bind()
popup.open()
def getwlbtstate(self):
return walascan.mainAntennas()
def on_waybill(self):
waybill.bind(text=KartScan.on_text_validate)
# popup = Popup(title='Result',
# content=Label(text=waybill.text),
# size_hint=(None, None), size=(100, 100))
# popup.bind()
# popup.open()
return waybill.text
if __name__ == '__main__':
KartScanApp().run()
kv file
TextInput:
on_text: print(self.text)
You could use on_text to call a function when the text changes. I think it sometimes even triggers when no change has occured.
TextInput has a text property, and in kivy, all properties have associated on_xxx events, that you can bind to to react to them, so when reading the doc, even if it's not explicitly mentionned for them, everytime you see something is defined as a Property (or any subclass of it, like StringPropertyNumericProperty,ObjectProperty,AliasProperty`).
TextInput:
on_text: do_something(self.text)
or in python
t = TextInput(text='', on_text=do_something)
or
t = TextInput(text='')
t.bind(on_text=do_something)