KIVY python - change TextInput color - kivy

Question

I want to change the color of text contained in the TextInput when it is modified by the user.
Example:
There is a text input, with a 'pre-written' text inside
If you modify a character of this text, its color immediately changes to red
debug2.py
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
class MyDebug(BoxLayout):
def __init__(self, **kwargs):
super(MyDebug, self).__init__(**kwargs)
Builder.load_file("debug2.kv")
class MyAppli(App):
def build(self):
return MyDebug()
if __name__ == '__main__':
MyAppli().run()
debug2.kv
#:kivy 1.9.1
<MyDebug>:
TextInput:
text: "Edit me !" # change color to (1, 0, 0, 1) when modified
foreground_color: (0.3, 0.4, 0.5, 1)

Answer 1

Here you go
py:
class ColorTextInput(TextInput):
def changetored(self):
if self.text != "Edit me !":
self.foreground_color = (1,0,0,1)
kv:
ColorTextInput:
text: "Edit me !" # change color to (1, 0, 0, 1) when modified
on_text: self.changetored()

Answer 2

You add a method into your root widget, MyDebug and an event, on_text into your kv file as follow:
Snippet
debug2.py
class MyDebug(BoxLayout):
def __init__(self, **kwargs):
super(MyDebug, self).__init__(**kwargs)
def on_text_change(self, instance, value):
instance.foreground_color = (1, 0, 0, 1)
debug2.kv
<MyDebug>:
TextInput:
text: "Edit me !" # change color to (1, 0, 0, 1) when modified
foreground_color: (0.3, 0.4, 0.5, 1)
on_text: root.on_text_change(self, self.text)
Output

Answer 3

Easiest way to change the color of the text is to use on_text
TextInput:
text: 'Color will change from black to red if text is modified'
on_text: self.foreground_color = (1,0,0,1)##red
foreground_color = (0,0,0,1)

Answer 4

You can use the example below:
TextInput:
id: txt_add_data_trial
multiline: True
cursor_color: app.theme_cls.primary_color
font_family: 'Roboto'
font_size: '20sp'
size_hint: 1, None
height: '60dp'
foreground_color: app.theme_cls.primary_color if self.focus==True else self.disabled_foreground_color
background_normal: './assets/imgs/transparent.png'
background_active: './assets/imgs/transparent.png'
canvas.after:
Color:
group: "color"
rgba: app.theme_cls.primary_color if self.focus==True else C('#d3d3d3')
Line:
group: "rectangle"
width: dp(1.25)
rectangle: (self.x, self.y, self.width, self.height)