Kivy : Relative size of text displaying in a popup - python-2.7

Question

Is there any way to make the message/title in the label fits into the popup ?
'message' or 'title' can be a long text that goes beyond the borders of the popup .
def popup_display(self, title, message):
btnclose = Button(text='Close me', size_hint_y=None, height=50)
content = BoxLayout(orientation='vertical')
content.add_widget(Label(text=message))
content.add_widget(btnclose)
popup = Popup(content=content, title=title,
size_hint=(None, None),
size=(300, 300),
auto_dismiss=False)
btnclose.bind(on_release=popup.dismiss)
popup.open()

Answer 1

Label has a text_size property, which allows to constraint its size to given bounding box. You can bind it to available size:
#!/usr/bin/python
# -*- coding: utf-8 -*-
from kivy.uix.popup import Popup
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.app import App
from kivy.lang import Builder
from functools import partial
class TestApp(App):
def build(self):
return Button(on_press=partial(self.popup_display, "title", "bar "*80))
def popup_display(self, title, message, widget):
btnclose = Button(text='Close me', size_hint_y=None, height=50)
l = Label(text=message)
l.bind(size=lambda s, w: s.setter('text_size')(s, w))
content = BoxLayout(orientation='vertical')
content.add_widget(l)
content.add_widget(btnclose)
popup = Popup(content=content, title=title, size_hint=(None, None), size=(300, 300), auto_dismiss=False)
btnclose.bind(on_release=popup.dismiss)
popup.open()
if __name__ == '__main__':
TestApp().run()
Text that won't fit will get removed. If you want to have it all you should use ScrollView inside of your popup.
As for title, it's not a Label but a string, so the best you can do is to add newlines:
return Button(on_press=partial(self.popup_display, "multiline\ntitle", "bar "*80))

Answer 2

Here'a a simpler version without BoxLayout and Button:
#!/usr/bin/python
# -*- coding: utf-8 -*-
from functools import partial
from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.popup import Popup
class TestApp(App):
def build(self):
return Button(on_press=partial(self.popup_display, "title", "bar "*80))
def popup_display(self, title, message, widget):
l = Label(text=message)
l.bind(size=lambda s, w: s.setter('text_size')(s, w))
popup = Popup(content=l, title=title, size_hint=(None, None), size=(300, 200), auto_dismiss=True)
popup.open()
if __name__ == '__main__':
TestApp().run()
Simply click outside the popup to close it.