Kivy: custom settings password entry

settings.json

[
{"type": "password",
 "title": "PASSWORD",
 "section": "test",
 "key": "pw"}
]

settingstest.py

import kivy
kivy.require('1.8.1')

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.settings import SettingString
from kivy.uix.label import Label


class PasswordLabel(Label):
	pass


root = Builder.load_string('''
<SettingPassword>:
	PasswordLabel:
		text: '(set)' if root.value else '(unset)'
		pos: root.pos
		font_size: '15sp'

Button:
	on_release: app.open_settings()
''')


class SettingPassword(SettingString):
	def _create_popup(self, instance):
		super(SettingPassword, self)._create_popup(instance)
		self.textinput.password = True

	def add_widget(self, widget, *largs):
		if self.content is None:
			super(SettingString, self).add_widget(widget, *largs)
		if isinstance(widget, PasswordLabel):
			return self.content.add_widget(widget, *largs)

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

	def build_config(self, config):
		config.setdefaults('test', {'pw': ''})
		print 'pw:', config.get('test', 'pw')

	def build_settings(self, settings):
		settings.register_type('password', SettingPassword)
		settings.add_json_panel('Settings', self.config, filename='settings.json')

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

Thank you so much for this gist.

Here is if you want to show the '*' in Label for password:

root = Builder.load_string('''
<SettingPassword>:
    PasswordLabel:
        text: (lambda x: '*'*x)(len(root.value)) if root.value else ''
        pos: root.pos
        font_size: '15sp'
Button:
    on_release: app.open_settings()
''')

I want to encrypt passwords rather than storing them in plain text in the .ini file, so I added a _validate method to the class. This gets called automatically when "OK" button is clicked. This is just a placeholder -- the encryption function is a separate exercise.

> class SettingPassword(SettingString):
>     def _create_popup(self, instance):
>         super(SettingPassword, self)._create_popup(instance)
>         self.textinput.password = True
> 

    def _validate(self, instance):
        self._dismiss()
        value = self.textinput.text.strip()
        self.value = value + "Encrypted" #Change this to your encryption
        print(self.value) #Just for debugging

>     def add_widget(self, widget, *largs):
>         if self.content is None:
>             super(SettingString, self).add_widget(widget, *largs)
>         if isinstance(widget, PasswordLabel):
>             return self.content.add_widget(widget, *largs)